Top Banner
FURNITURE RESTORATION Tightening loose chairs is one furniture repair most homeowners avoid. Everyone assumes you need dozens of clamps, a special glue and knowledge akin to black magic to repair a chair - not so. Your total expenditure for repairing every loose chair in your home should be less than $50.00, even if you have to buy everything I list. Since the explanation takes more space than I have here, we’re going to do this project in two parts. This column will be on taking a chair apart - next time we’ll cover the assembly process. For now, we’ll assume the chair is loose, but nothing is broken. Replacing broken parts is a whole other ball game. The first consideration is the type of chair. If you have a typical dinette set (informal) the chairs have legs that are not perpendicular to the floor and all the joints are glue joints. The legs are glued directly into the bottom of the seat with no screws. Dining room chairs (formal) typically have legs parallel to each other (or nearly so), perpendicular to the floor. The cushioned seat is attached with screws, and the corners of the frame immediately below the seat are held together with a block in each corner that is screwed and glued in place. Most chairs will fit into one or the other of these two categories, or perhaps combine features of both. You’ll need a rubber mallet (wrapping an old sock around a regular hammer will NOT work). This will run less than $10.00. 16 to 24 ounces is heavy enough. A roll of 1" masking tape, a pencil, a screwdriver (maybe) and a sharp pocket knife will complete your tool list for disassembly. First put a piece of masking tape on each part of the chair to mark its position. I use a simple abbreviation code; RF=right front, LF=left front, etc. Mark each piece; all four legs, the stretchers that run between the legs front to back on each side, and, if there are any, the stretcher(s)
39
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: Fur restoration

FURNITURE RESTORATION

Tightening loose chairs is one furniture repair most homeowners avoid. Everyone assumes you need dozens of clamps, a special glue and knowledge akin to black magic to repair a chair - not so. Your total expenditure for repairing every loose chair in your home should be less than $50.00, even if you have to buy everything I list. Since the explanation takes more space than I have here, we’re going to do this project in two parts. This column will be on taking a chair apart - next time we’ll cover the assembly process.

For now, we’ll assume the chair is loose, but nothing is broken. Replacing broken parts is a whole other ball game.

The first consideration is the type of chair. If you have a typical dinette set (informal) the chairs have legs that are not perpendicular to the floor and all the joints are glue joints. The legs are glued directly into the bottom of the seat with no screws. Dining room chairs (formal) typically have legs parallel to each other (or nearly so), perpendicular to the floor. The cushioned seat is attached with screws, and the corners of the frame immediately below the seat are held together with a block in each corner that is screwed and glued in place. Most chairs will fit into one or the other of these two categories, or perhaps combine features of both.

You’ll need a rubber mallet (wrapping an old sock around a regular hammer will NOT work). This will run less than $10.00. 16 to 24 ounces is heavy enough. A roll of 1" masking tape, a pencil, a screwdriver (maybe) and a sharp pocket knife will complete your tool list for disassembly.

First put a piece of masking tape on each part of the chair to mark its position. I use a simple abbreviation code; RF=right front, LF=left front, etc. Mark each piece; all four legs, the stretchers that run between the legs front to back on each side, and, if there are any, the stretcher(s) running left to right. Mark the stretchers so you can tell which end goes in front, back, left or right. These pieces may look symmetrical but chances are they aren’t. They must go back in the same position the were in originally. With a formal chair, also mark the rails, those board-like pieces immediately beneath the seat cushion.

With a formal chair, remove the upholstered seat and the screws holding the wooden corner blocks in place. Number the blocks and the inside of the rail so you can put the blocks back where they came from.

Now for see what you can pull apart just by wiggling and pulling on the pieces. After you’ve removed what you can, go after the stretchers, if they haven’t already come out. Use the mallet to hit the leg, swinging parallel to the stretcher. Hit as close to the joint as possible, holding the stretcher tightly. Continue this process until the stretchers are removed.

Page 2: Fur restoration

Having removed the stretchers, the legs should be looser than they were, if not falling out. Use the same process to separate the legs from the rails (on a formal chair) or, on an informal chair turn the piece upside down, striking the seat bottom with the mallet while holding the leg to be removed. Always try to hit as close to the joint as possible, swinging in line with the piece you’re trying to remove. You want to pull it out, not break it off. Do this over a padded surface. If the piece separates suddenly, remember you’re holding only part of it...the rest will fall. One last note: some joints will be just as tight as the day they were originally glued. The old adage, "If it ain’t broke, don’t fix it" applies. If you can’t get a joint apart without extreme extertion, leave it alone.

After you’ve congratulated yourself on getting the piece apart without breaking anything, take a break. We’ll clean this chair up and put it back together in our next column. As always, if you have any questions on this or other furniture problems, drop me a line at the Enterprise.

Page 3: Fur restoration

Furniture Tips and Tricks

Got the chairs apart, did we? No mashed fingers or broken parts? Good! Now let’s make ‘em like new again.

You’ll need a pocket knife with a small blade; an 8 ounce bottle of Elmer’s Carpenters Wood glue; the shortest coil available of sash cord (ask for it by name). This looks like clothes line, but it isn’t. Sash cord is the woven cotton rope that was used to hold sash weights in old fashioned windows. If you have a choice, get the larger diameter. Get 3 feet of 5/8" dowel rod. Cut this into 1 foot lengths. You’ll also need an old cotton T shirt cut up into small rags, a section of newspaper, some Q-tips, and a small pan of water.

Hold the knife at a right angle to the dowel/tenon and scrape the old glue off. Don’t cut - scrape. Get it off all the dowels and the tenon ends of the stretchers. Using the small blade, scrape the glue out of the holes that held the dowels and tenons. Again, scrape. You don’t want to cut the wood down, just remove the old glue. If the joints are not cleaned properly, the new glue will not adhere.

Using your masking tape markers as guides, put the chair back together. No glue, yet. This is a dry fit, to make certain you’ve thoroughly cleaned the holes and not left any burrs elsewhere that will hinder the assembly when you do glue it. Correct anything that doesn’t fit.

Whether you’re working with formal chairs (cushion seat) or dinette chairs (legs attach directly to the seat) here’s the assembly process. Fold the newspaper to get a square 4 or more layers thick. Put a puddle of glue on it about the size of a silver dollar (ask your grandfather).

For dinette chairs: using a Q-tip, spread the glue (you want to get a film of glue. If the glue runs at all, you’ve got too much.) over the tenons of the stretcher and into the holes the tenons go into. If there is a left to right stretcher, fit it into the two side stretchers first, then insert them into the legs. Spread the glue over the leg tenons and their matching holes in the seat, and insert them. On a chair that was just slightly loose before, you may have to use the mallet to drive them in. You should give them a good tap, anyway, just to make certain you drive them home. Set the chair upright on a flat surface. Take a length of sash cord long enough to go around the chair at the feet, and tie a knot in it. The cord should be slightly loose. Insert a section of dowel rod between the cord and the chair, and turn it clockwise to form a tourniquet. Keep turning it to tighten the cord and drive the tenons completely into place. Angle the dowel so it catches on the chair seat (or a stretcher) and can’t unwind. Dip a rag in the water and wipe off the squeezed out glue. Dry the joints with another rag. Set it aside overnight.

Page 4: Fur restoration

For formal chairs, spread the glue as before to attach the front rail to the two front legs. Assemble stretchers as above, then put the side stretchers into the front legs. Put the side rails into the front legs. Lay the chair on its back on the floor. Position the stretchers and side rails over the holes and drive them into place with the mallet. Set the chair upright on a flat surface. Take two sections of sash cord; one around the rails, the other around the legs at the stretchers. Wind up both with dowel rods uniformly to tighten the joints. Wipe off glue as before and leave to dry. Corner blocks can be replaced after the frame has set up.

Be sure to put the chairs on a flat surface while tightening. This insures that all four feet meet the floor. As always, if you have any questions, just drop a line to me at the Enterprise. Next time we’ll tackle something a little less ambitious, but useful, nevertheless.

 

Page 5: Fur restoration

Furniture Tips & Tricks

Color is always a consideration in furniture whether you’re buying new or refinishing. As important as color is it’s amazing how little the average person knows about it. In this column we’ll try to add to your education. Be warned, this is a reader-participation column...you’re going to have to do something in order to get the full benefit!

 When talking to a painter, decorator, or anyone who deals with color all the time you’re liable to hear enough strange terms to make your head start spinning. Primary, secondary, complementary...what are they talking about? Take a piece of paper and draw a triangle. Label each corner of the triangle with one of the following; Red, Blue, Yellow.

 These are the primary colors. All other colors are made by mixing one or more of these colors together, combined with black and/or white to get various shades. Now on the line between the primary colors, place the following labels; between red and yellow, place orange; between red and blue, place violet; between yellow and blue, place green. These are the secondary colors. These colors are made by mixing the adjacent primary colors. Add white, you get a lighter shade; add black, you get darker. Complementary colors are those directly across from each other. For instance, directly across from Red in our triangle is Green. Green and red are complementary colors. Theoretically, mixing any two complementary colors together should give black. It practice, you get a dark brown.

 You often hear talk about "warm" and "cool" colors. Warm colors include red, orange and yellow; cool colors would include blue, green, and violet. In decorating, warm and cool colors are used to emphasize or de-emphasize room areas. In paintings, particularly in portraits, cool colors are used as a background in order not to detract from the subject of the painting. Warm colors are also used in paintings (along with perspective) to draw your attention to a particular point in the painting.

Color is very important in the choice of woods for furniture. Mahogany and walnut traditionally have imparted a "rich" look. Oak, pine and maple, less so, leaning more to function and practicality. Each species of wood (a subject for another column or two) has its limitations as far as color is concerned. It would be very difficult to make mahogany as light as pine. Because of the grain (which is a function of color) it would be nearly impossible to make oak look like anything else.

Color matching in stains is not difficult once you understand what the color you see is composed of. A deep, rich mahogany has blue and red in it. A medium oak has yellow/orange and black (believe it or not!). The traditional (30's,40's & 50's) reddish maple has a reddish/orange and black.

Page 6: Fur restoration

As you might have guessed, most refinishers don’t use pure colors for furniture. We use the same color charts artists do, and not for any over-appreciation of our skills. We use them because the color names used by artists are universal. Just as a passing note, here are the colors I keep in my shop that I use to mix and match stains: Burnt Sienna, Raw Sienna, Burnt Umber, Raw Umber, Van Dyke Brown, Thalo Blue, Thalo Green, Vermillion, Chrome Yellow, White and Black. These are all oil based colors I use to make stains and glazes, as well as minor touch-up work.

Page 7: Fur restoration

Distressing WoodOld is hip and a seemingly important part of any project nowadays is the ability to falsify its age. Distressing -- also known as antiquing -- is used to age contemporary pieces and there are many variation on this theme. One of the more extreme approaches is to throw the project into the sea and let it crash against the beach for a few hours, if not days (it helps to tie it to something solid so that it doesn't float away of course!). Below are a few of the more accessible ways to age your projects. But, the best guide of all is to look at original antiques to try and mimic the same marks and scratches. Having said that, do not try to fake the marks with a chisel or knife as these will look false.

1. Nuts and bolts

Take a handful of nuts and bolts and put them in a canvas bag. Use this to strike the wood, producing dents and bruises in the wood's surface. Make sure that you hit the wood in a random fashion: do not plan out a hitting strategy first, as this tends to result in a regular pattern. Concentrate on the edges of a table and on the legs -- areas where the most wear and tear is likely to occur in old furniture.

2. Stain

Once distressed, smear the surface with a water-based stain. Take special care to run the stain into all of the dents and bruises so that they will appear darker. Once the stain is satisfactory, seal the wood using a shellac sealer. This will hold the stain in.

3. Cup Rings

Old table tops typically suffer from cup rings. These are caused by mugs of steaming-hot coffee being placed onto the wood, or by a film of alcohol on the underside of a beer glass. To replicate such a mark, fill a round-based metal container (such as a canned food tin) with hot water and wet its underside. Leave this on the wooden surface for about ten minutes to produce a dark ring.

4. Dirt stains

Mix alcohol and pigment with French polish and apply with a brush. Cover the entire surface with this concoction and rub well into the wood to create a darker finish. After this mixture has dried, apply a coat of clear polish. Once this has been applied, buff the product using firstly a circular motion, but finishing with a straight motion (with the grain). Stop short of creating the sheen that you would usually want to make. Once this is done, rub 000 wire wool along the grain to dull the polish a little more.

Page 8: Fur restoration

5. Paste Wax

Finally apply a coat of dark-colored paste wax to increase the aged appearance of the piece.

Page 9: Fur restoration

Preparing Furniture for Refinishing

Home furnishings are a major investment. According to one study, furniture ranked first on the list of household objects cherished most. With proper care, furniture can be a lifetime investment.

Wood is the most popular material used for furniture, but some woods are easily damaged or dented and others have poor finish. Refinishing makes it possible to restore existing furniture, to rehabilitate second-hand pieces and to preserve family furniture treasures. Whether you're motivated by the love of a specific piece, the need to save money or the desire to save natural resources, refinishing may be the answer.

Refinishing furniture is not difficult or expensive. Finishes and equipment are available in a variety of price ranges and success is practically guaranteed if directions are carefully followed. Successful refinishing, however, depends upon the care and thoroughness with which the old finish is removed and the surface cleaned and sanded. Careful work takes time and good finishes can't be hurried, so work leisurely and enjoy the results.

Remove old finish

Remove all parts from the furniture that are not to be refinished, such as drawer pulls, glass knobs or mirrors.

Use a good commercial paint or varnish remover. There are now wax-free products on the market that are not flammable. An average-size table or small dresser should require about one pint of remover.

It is generally not economical or advisable to make removers at home; the procedure is dangerous and the product is not always effective.

Avoid using a lye mixture because it raises the grain of the wood, discolors the wood and affects the final finish.

Apply remover as directed on the container to a small area, brushing in one direction only. When the surface appears softened and wrinkled (5 to 20 minutes), remove the finish with a putty knife, spatula or commercial scraper.

Be careful when using liquid removers or water on veneer surfaces. Too much moisture causes panels to pull and the glue to soften.

Hold the scraper at an angle to prevent gouging the wood. Use long, even strokes, following the grain of the wood, to remove the finish.

Page 10: Fur restoration

All of the old finish should be carefully removed in carved, fluted or turned surfaces. A vegetable brush, an orange wood stick or a pad of steel wool will help with turnings or grooves. A piece of twine or cord dipped in remover and pulled through fine grooves will also help. Sawdust or excelsior can be used to rub off old finish.

Rinse as directed on the container or wash with denatured alcohol or turpentine. A wax-free remover does not require washing the surface.

There are some times when the old finish does not need to be removed, and you may put a new coat of finish over the old one. In that case, first remove any wax or oil by washing with turpentine. Use sandpaper or pumice and water on the surface.

Allow the wood to dry thoroughly before the next step (24 to 48 hours).

Glue loose joints

It is best to take the pieces apart if joints are loose. Before doing this, label the parts so that they may be reassembled correctly. When pieces must be forced apart, put a heavy pad or block of wood between the hammer and the wood.

Scrape off the old glue with a knife or razor blade. Do not sand; the joint must not be reduced in size or the pores closed. Wash off old glue with steel wool and a solution of warm vinegar and water in equal parts. Dry thoroughly. If the wood surfaces to be glued are smooth, slash the surface with a knife so the glue can hold better.

Plastic resin glue is most satisfactory to use. It is waterproof, does not stain wood, handles easily and makes a strong bond. It is sold under various brand names in powder form.

After the surfaces are well cleaned and dried and the joints are made to fit each other, the glue should be spread on both surfaces in a medium thickness. Both the glue and the wood should be warm (75 to 80 degrees F).

Ease the dowels and tenons into the holes to prevent air pockets. Immediately place joint under pressure using clamps (such as a bar, cabinet or C-clamp). Protect the furniture surface under clamps with pads of cardboard or cloth. Allow to dry under pressure at least 24 hours.

Raise dents

Raise shallow dents by placing a damp woolen cloth or wet blotting paper over the depression; then hold a hot iron over the cloth until the steam swells the

Page 11: Fur restoration

wood to eliminate the dent. Sand when dry. This treatment cannot be used for veneer.

Fill cracks and holes

Use stock shellac to fill cracks and holes where hardware has been removed.

If the piece of furniture is to be stained, select the shellac color and fill the holes after the stain is applied. Wet a spot on the wood with turpentine or alcohol to find out what the final color will be. The shellac will be darker in the stick, so melt some of the shellac and test its color. If the exact color is not available in the stock, you can sometimes make a match by blending two colors together.

Clean out cracks and holes and smooth the edges before filling. Melt the shellac with a heated steel knife. When hardened, shave off excess shellac level with the surface.

Remove dark spots

Remove dark spots by sanding or bleaching. Too severe treatment will remove the lovely quality that age has given the wood.

Commercial bleaches are available with clear directions.

An oxalic acid solution may be made using 1 ounce (2 tablespoons) oxalic acid powder or 2 ounces (4 tablespoons) oxalic acid crystals to 1 pint of warm water. Apply the solution with brush, cloth or sponge. Let stand 10 to 20 minutes. Repeat as necessary. Wash with ammonia solution (1 tablespoon ammonia to 1 quart water) or with a solution of 2 tablespoons borax dissolved in a pint of water. Rinse with clear water. Caution: Oxalic acid is poison.

Household laundry bleaches (sodium hypochlorite) will bleach most woods several shades lighter, with the exception of oak, which may turn slightly darker and brown. It will change the color of the dark streaks in poplar to the yellow green color of the rest of the wood, but it will not effectively bleach the yellow green.

Sand

Much of the beauty of the finished wood will depend upon sanding. The finish you choose will not cover up scratches and dents. In fact, the finish magnifies blemishes of any kind.

The correct grade of abrasive must be selected for best results. On smooth wood start with fine; on rough wood start with medium. Then continue with successively finer abrasives.

Page 12: Fur restoration

Garnet paper is better for all-round household use. It is reddish in color and costs a little more than flint, but it is harder and sharper, so lasts longer.

Smooth the surface by sanding with the grain of the wood when the wood is dry. Cover adjoining cross grain sections of the wood before sanding.

When sanding flat surfaces, it is convenient to wrap the sandpaper around a small block of wood or a blackboard eraser in order to ensure even pressure.

For grooves and crevices, fold squares of sandpaper in quarters. Folding the sandpaper over itself will keep it from slipping. You can use fine steel wool although it may discolor some woods such as oak. Emery cloth torn in strips is excellent for smoothing deep turnings when used shoe-shine fashion.

Wipe the sand dust from the surface frequently with a cloth dampened in turpentine.

Be sure the wood is smooth as glass.

Stain

Stain brings out the beauty of the wood and helps match varying shades of wood. If your wood has a nice natural color or if the stain has not been removed, you will not need to use stain. Remember that any type of clear finish will darken the wood somewhat and magnify the beauty of the grain and wood pattern.

Oil stains are easy to apply and allow for better color control. Walnut and mahogany colors mixed in varying proportions will produce most of the desired shades. Varnish stain is not recommended.

Be sure to test the stain because woods vary greatly in character. Soft woods absorb stain and darken quickly, while hardwoods do not darken readily. Some woods, especially fir plywood, have both extremely hard and soft portions. When stained, they will show contrasts of light and dark that are not pleasing. To avoid this, apply a penetrating seal to the entire surface before staining. End grain surfaces are very absorbent and should be sealed with a mixture of 5 parts alcohol to 1 part clear shellac.

Test on a hidden part of the furniture. Wipe off with a soft cloth in the direction of the grain. If too dark, add turpentine to the stain and test again. Repeat the application if the shade is not dark enough. A built-up color is clearer and softer than a one-coat job. As a rule, amateurs use stains too liberally.

When the shade appears satisfactory, apply the stain evenly to small areas at a time. Wipe off with a soft cloth with the grain of the wood. Allow the stain to dry

Page 13: Fur restoration

48 hours. Seal to prevent the color from mixing with the final finish and rub with fine sandpaper.

Sealers

Some stains, especially dark colors, should be sealed to prevent them from bleeding into the finish. You can use a ready-mixed sealer available at paint and hardware stores. Check the label to be sure the sealer is compatible with the finish you plan to use. You can also make a sealer from the final finish you plan to use.

VarnishMix one part varnish with one part turpentine.

ShellacMake a sealer of one part white shellac (4 pound cut) with eight parts denatured alcohol. Be sure to check the date on the shellac label. Old shellac will not dry properly.

Linseed oilMix one part linseed oil with three parts gum turpentine.

Tung oilDip a piece of nylon hose in tung oil. Wipe on the wood and immediately wipe off the excess.

Brushing lacquerBrush on some lacquer and immediately wipe it off.

Applying a sealer

NoteNot for tung oil or brushing lacquer.

Apply a thin coat of sealer with a brush. Brush slowly with the grain. It will soak in according to the hardness of the wood.

Keep the surface wet with the sealer for 10 to 15 minutes by applying more coats as each soaks into the wood.

Wipe off all excess sealer with a nylon hose or a soft, lint-free cloth. Allow 24 hours for drying. Lightly smooth the surface with fine sandpaper or 000 steel wool. Remove any dust by wiping with a tack cloth.

Do a quality check

Much of the final finish depends on how well the surface has been prepared.

Ask yourself these questions:

Have necessary repairs been made?

Page 14: Fur restoration

Is the surface: o Clean? o Smooth? o Old finish removed? o Cracks and holes filled? o Sanded smooth as glass? o Filler used on open-grain woods? o If it is stained, was only enough used to enhance the beauty of the

wood?

Page 15: Fur restoration

Reflections Again

Refinishing Tips

1. Filling small gouges and cracks - 03/26/99

When filling small cracks and gouges on raw wood I use one of the commercial wood fillers (Fix Wood Patch, Famowood Wood Filler-available at local hardware stores). Instead of using it directly from the can I thin it with acetone. I put the thinned filler into a plastic syringe (available in hobby stores, hardware stores, or Constantine's Woodworkers Catalog 800-223-8087) and squeeze it into the spot I'm filling (slightly over filling). This works well because I can avoid getting the filler into the surrounding grain. Next, I sprinkle the filled area with talcum powder and pat the filler into the crack or gouge with my finger. This serves to pack the filler into the damaged area without the filler sticking to my finger. I let the filler dry, blow off the talcum and hand sand (backed with a sanding block) with 180 grit paper. Sand the filler level to the surrounding surface. The trick is to sand gently. It will take a few moments longer, but it will avoid tearing out the filler. It's best to let the filler dry over night before sanding to allow for any shrinkage of the filler.

2. Removing water spots or rings from furniture - 04/09/99

Water rings and spots are caused by moisture trapped in the finish when wet objects are left on the furniture. They appear as white cloudy areas. There are several ways to approach the problem:

A substance with oil in it, furniture polish for example, can be left on the spot overnight. Wipe off the oil in the morning. With luck, the spot will be gone. Alcohol can be used to remove the spot. Dampen a soft rag lightly with alcohol and wipe the area gently. Be careful. Alcohol can damage some finishes, especially shellac. Use a small amount of alcohol and proceed cautiously. Mild abrasion can remove the water damage. Use rottenstone and/or pumice with a rubbing oil (available at finer hardware stores or Constantine's Woodworkers Catalog 800-223-8087). Proceed with care. You don't want to rub through the finish. #0000 steel wool (available at hardware stores) will also work, but it is more abrasive. Rubbing out the water mark may alter the sheen of the finish. If this happens, you will have to rub out the entire surface to get an even sheen. Another solution is to coat the entire surface with the proper solvent. This will work with shellac or lacquer. If the finish is shellac use alcohol. Use lacquer thinner on lacquer finishes. You will need spray equipment for this method. Spray the entire surface with the proper solvent and the allow to dry. The solvent will dissolve the finish and allow the moisture to escape. When it dries, hopefully the damage will be gone.

Page 16: Fur restoration

 

If none of these things work, you may have to strip and refinish the furniture.

There are several things involved which can determine the result of your repair: type of finish, condition of the finish, age of the finish, thickness of the finish, depth of the water spot, and your experience and patience. Also, although the damage appears white and cloudy, it might not be water damage.

3.Removing finishing nails - 04/26/99

Sometimes when working on furniture I come across a finishing nail that is sunk down into the wood. I need to get the nail out and there's nothing to get a hold of to pry it out. The solution is to drill a slot around the nail. Take a piece of steel tubing about two inches long that will just fit around the nail. File teeth in one end of the tubing. Put the tubing in a drill and drill around the nail. Use a pair of wire snips to reach down and get a hold of the nail. Using a piece of wood to work against pry the head of the nail high enough so you can get to it with a hammer claw or similar prying device. After removing the nail you will end up with a larger hole which you can fill with putty or a wood dowel.

Page 17: Fur restoration

REPAIRING FURNITURE JOINTS

Building furniture with traditional joinery is fairly straightforward: cut, glue, clamp, and let it dry. A well made mortise and tenon or dovetail joint will last several generations, but even the best joint may eventually need to be repaired, particularly on hard wearing items like chairs. Re-cutting the original joinery or replacing an entire part may not always be the right course to follow, especially if the furniture has an intrinsic historical value. Discovering how the piece was originally made is sometimes half the battle. This article will take you through the basic steps to repairing the most common furniture joints - mortise and tenon, dovetail and dowel.

 

DIAGNOSE AND DISMANTLE

 

Besides accidental breakage, a joined piece of furniture may fail for a number of reasons. The most common are wear and tear which produce racking stresses on the joint (like the back legs of a chair) and normal expansion/shrinkage due to seasonal changes. These two forces may operate independently or together to produce failure at the glue line. A joint may also have been improperly cut when originally constructed with one of the components either too large or small.

To properly repair a furniture joint you should completely dismantle it and replace worn or damaged wood with wood from the same species. This advice is perhaps the most disregarded by well-meaning novices and even poorly-trained professionals. Nails, screws and metal brackets are often installed on loose joints in an effort to repair them. Glue dribbled into a partially opened joint and hot melt glue are also encountered. Besides these added fasteners, many production furniture pieces are pinned with small finishing nails which held the glued joint together until the glue dried, eliminating the need for clamps. Glue blocks are often employed to counteract racking on chairs and to re-reinforce joinery. Whatever fasteners you encounter, they need to be removed so that the joint comes apart easily. To pry out small nails you can regrind the outer jaws of end nippers so that they can pry out nails set flush with surface. On nails set below the surface you can try to push them through but I find it best to leave them. This will split the wood on the mating joint, but this is easier to repair than show wood gouged to access a small nail head. On old flat head screws, make sure the tip of the driver fits snugly in the slot to avoid stripping the slot. I keep an old driver that I re-grind to customize the fit for old screws. For frozen screws, hold a screwdriver in the slot and heat the shank of the screwdriver with a propane torch to transfer the heat to the screw. After the screw cools it should come out easily. If the slot is stripped, a screw extractor is a last resort.

Page 18: Fur restoration

If the joint was loose to begin with and you've removed all fasteners, the joint should come apart easily by hand. If not, there's probably some hidden fastener. Look the joint over carefully and look for any tell-tale holes. If you can, slip a metal feeler gauge into the joint. In some instances, screws are counter-bored into a show side and the hole plugged with wood from the same species. These can be hard to spot under a finish. If you encounter one, drill it out and re-plug it after repairing the joint.  

Glues

The type of glue used on the original joinery is important. Prior to the mid forties, hot animal hide glue was the traditional glue used in furniture assembly. After that time, PVA glues eventually replaced hide glue. Hide glue has some annoying application characteristics but it's redemption is in the fact that it is reversible. It can be "re-activated" with water and heat and it will re-bond to itself. This means that joints originally glued with hide glue do not have to scraped to bare wood to get the new glue to stick. Just re-apply some new glue after moistening the old glue with hot water. You can use either hot hide glue made from dry granules or pre-mixed hide glue like Franklin's. The pre-mixed variety will give you more open time to work than the hot type. You can also use a PVA glue to re-glue an old hide glued joint, but be very cautious with doing this on antiques. PVA glue is not considered reversible and will make any future repairs difficult.

Hide glue can be "de-activated" on joints that are still stuck by saturating the joint with alcohol. Squirt some alcohol (I use denatured alcohol) along the edges of the joint and it will wick in by capillary action. After several minutes the joint will be loose enough to pull apart.

PVA glues like Titebond and Elmer's are very difficult to remove. If you suspect that one of these glues was used, wetting the joint in hot vinegar loosens the joint enough to wiggle it apart. Unlike hide glue, PVA glue does not re-bond to itself so you must scrape off the old glue to bare wood. If you are gluing a broken piece of wood with irregular edges, soak the glue with hot vinegar and remove it with a brass bristle brush.

If you're not sure which glue was used you can do a simple test. Place a drop of hot water on the glue and wait several minutes. Hide glue will become sticky and PVA glues will turn white.

Other glues you may encounter are epoxy, urea-resin and super glue. All of these glues should be treated the same as PVA in that they are non-reversible. However, none of them can be softened to aid in disassembly. Since most of these glues are brittle, a sharp blow with a hammer usually breaks the glue line.

 

Page 19: Fur restoration

Stubborn Joints

In some situations a joint that is still properly or partially glued may need to be dismantled.

If the joint can be wiggled, lightly tapping it with a hammer and a piece of soft wood is usually enough to persuade it apart. If this doesn't work, placing it between bench dogs and running the tail vise in reverse will pull apart even the most stubborn joints. If the joint doesn't respond, snug the vise as far as you can and then whack the dog (not the joint) with a hammer. This will dissipate the blow of the hammer.

 TECHNIQUES FOR INDIVIDUAL JOINTS

The design of different joints necessitates different techniques in repair. For repair purposes you should acquaint yourself with the different types of joints. Although there are exceptions, the most commonly used joints in furniture construction are the mortise and tenon, dovetail and the dowel.

 Mortise and tenon

This is the most commonly used joint in furniture construction and the one most often in need of repair. It is used to joint wood with grain at right angles to each other, and because of this, the contrary expansion/shrinkage of the different members causes the glue to fail - loosening the joint. Cabinetmakers have been aware of this for centuries, so variations of this standard joint have been devised to keep the joint together when the glue fails. These include the pegged, offset pegged, through wedged, and fox-wedged mortise and tenon.

When a standard mortise and tenon joint fails it is easy to disassemble by de-activating the glue and pulling the joint apart. When the joint is pegged or wedged, the joint will be loose, but will still hold together. To disassemble these joints you need to remove the pins or wedges to get the joint apart.

 Through Pegs - Pegs that go completely through the joint and come out the other side can be tapped out from the other end. On old pieces these pegs are usually tapered and are usually driven from the show side so tap from the opposite side. If the pegs can't be tapped out easily, drill them out

Blind Pegs - Pegs that do not go through to the other side must be drilled out if they cannot be pulled out with pliers. On valuable pieces, this should only be done if restoration of structural integrity is the primary consideration. Use pegs of the same species and hand whittle them to duplicate original construction.

 Offset pegs - Pegs that are driven in offset holes in the tenon are impossible to distinguish from blind or through pegs unless the joint is taken apart. This joint

Page 20: Fur restoration

will rarely loosen enough to be a structural problem unless the surrounding wood becomes weakened through rot or woodworm. If you run into holes that don't line up when the joint is re-assembled, they're offset pegs so do not re-drill the holes to line them up.

 Wedged Through Tenons - If a through tenon does not pull apart easily when the glue is de-activated the tenon may be wedged. In most cases the wedges will be of a contrasting or slightly dissimilar wood and be easy to see. You can pull them out after drilling small holes into the wedges In other cases, particularly glue-less Oriental joinery, the wedges are made from the same wood and are difficult to spot. You'll need to drill two sets of holes with a 3/32" drill bit from each end of the tenon which should be enough to collapse the tenon as you pull it out of the mortise.

 Blind (Fox) Wedged Tenons - These are very difficult joints to spot. If you can pull some of the joint out then it abruptly stops, it probably is fox wedged. If you can spot the bottom of the wedge, you can usually get a drill up into the wedge to drill it out to collapse the tenon. Make a new wedge from a very hard wood like maple and re-assemble. Do not use a thick wedge since it may split the grain of the tenon beyond the shoulder.

 Windsor chairs - The undercarriage and seat of Windsor chairs are traditionally assembled using green wood. This design produces a locking tenon that resembles a ball. Though loose, this joint can be swiveled around like a ball and socket. It can only be dismantled by drilling a series of holes with a small drill bit to waste away wood at the center of the tenon to collapse it. The joint is re-assembled using a fox-wedge technique.

 Rebuilding a Mortise and Tenon

If the mortise does not make good wood-to-wood contact when it's re-glued or you had to scrape away a lot of wood to remove glue, you need to build up the cheeks of the tenon to get a good fit. Simply glue two pieces of veneer cut slightly oversize to the tenon cheeks, taking care to orient the grain the same way and using wood of a similar species. Don't glue on one side only, this will change the offset the tenon When the tenon is broken off, you must rebuild the end of the tenon. Cut away the broken parts flush to the shoulder and drill a series of holes 1"-1-1/2" deep using a drill bit the same diameter as the width of the original tenon. (Hold the piece in a padded vise to avoid splitting the wood when drilling and chopping out the waste.) Then cut a piece of wood to splice into the old wood, using the original mortise to size the width.

Clean up the drill holes by paring the holes with a sharp chisel until you have a good fit with the insert piece. Make sure the grain is the same orientation, then glue the insert in.

Page 21: Fur restoration

Round tenons broken at the shoulder present a problem. Rarely does the design present enough "meat" below the shoulder to accept a dowel of the same diameter as the tenon hole. The best way to repair these are to cut off the tenon end below the shoulder at an angle of 30 degrees or less. A new piece of oversized wood is glued on (this is called a scarf joint) and then planed and spoke-shaved to the original profile. Round tenons can be enlarged to fit into oversized mortise holes by either wrapping the tenon in a glue soaked plane shaving or by expanding the tenon diameter with a wedge.

Mortises that are cracked or split can be re-glued as long as the wood closes snugly so that the glue will stick. If not, a new piece of wood should be spliced in and the mortise re-sized to fit the tenon.

Dovetails

Dovetails are another classic joint that form a mechanical lock in addition to the glue bond from the mating wood surfaces. Like the mortise and tenon there are many variations of this joint. The most common versions found on furniture are through, half blind and sliding. Through dovetails are found on many case pieces and drawers. Half-blind dovetails are the traditional favorite for drawer fronts and sliding dovetails are used for legs and crests of chairs.

Through and half blind dovetails - These two joints are found most often on drawer construction and the biggest problem is a broken pin or tail. After disassembling the joint, a new piece is spiced in, then pared down until it fits with the mating joint.

 

Sliding dovetails - The biggest problem with these are when they are used on legs joined to turned pedestals. When the leg is racked or some other type of stress applied, the grain of the pedestal cracks. Repairing the joint is easy, but getting it apart is not due to the amount of long grain on the pedestal. Drilling small holes down the outermost points of the male portion of the joint and injecting alcohol or hot water will usually coax the joint apart.

Dowels

Since the mid 1850's dowels have been used as replacements for the mortise and tenon, dovetail, and other traditional joints. Though despised by purists, proper doweling creates a very strong and durable joint. Like any other joint, stresses and contrary wood movement will invariably loosen the dowel in at least one of the components and it should be re-glued or replaced.

Many times a dowel will simply loosen when the grain of the dowel is at a right angle to the grain of the component. The joint can be tapped apart with a soft

Page 22: Fur restoration

faced mallet and then re-glued. Other times the dowel will break and the old dowel must be drilled out and replaced. If the new dowel does not seat exactly like the old one, misalignment of the joint will result. The technique below solves this problem

Replacing a Dowel

Begin by cutting the dowel flush to the surface of the component with a sharp saw. Using a sharp brad point bit 1/32nd-1/16th smaller than the diameter of the dowel, drill out the center of the dowel. Hold the part in a padded vise. When the bit reaches the bottom of the dowel hole, you will feel the bit "slip" a bit and you can stop. Using a sharp gouge with a sweep that matches the curve of the dowel circumference, pare the excess dowel away from the sides of the hole. To clean the hole run a drill bit the correct diameter backwards. (A new bit can catch and rip the hole apart if run forward.)

Don't use new dowels to check the fit. These can seize in the joint and become difficult to remove. Use dowels that have been pared or sanded undersized. These are easier to remove after a trial fit.

REASSEMBLE AND TOUCH-UP

The choice of glue that you use to re-assemble the pieces is up to you, but most restorers and conservators agree that hide glue is the best choice for antiques because of it's reversibility. Hot hide glue allows a quick initial tack and the pre-mixed cold glue will allow for a much longer open time for complex re-assemblies like chairs. There are arguments that PVA glue is stronger, but both hide glue (hot and cold) and PVA's form a glue line which is stronger than the structure of the wood, so either type can be used.

On some exposed replacement parts like pins, tails, or round tenons, the new wood can be toned to match the surrounding finish by mixing some dry pigments with shellac or lacquer and toning the replacement part to blend in. Working the color in thin layers to build up to the original color works better than trying to hit the color all in one shot.. When the color is right, apply a clear topcoat to protect the touched-up area.

Page 23: Fur restoration

SAVING THE FINISHSooner or later, every woodworker is faced with the prospect of refinishing an old piece of furniture. Whether it's a treasured "find" at a flea market or auction, or a favor for a relative or friend, etc., most people consider stripping off the old finish and refinishing the only option of successfully restoring the appearance of the piece.

Although I am a professional finisher, stripping furniture is the most thankless task in our shop. Despite the fact that we have proper application and exhaust equipment for handling the chemicals used, the process is messy and time consuming. For do-it-your-selfers, or woodworkers with limited shop space, the process is now a littler easier with the advent of "safer" strippers, but nonetheless, I don't know anyone who relishes the idea of spending a weekend with a couple gallons of stripper and a paint scraper.

When many woodworkers see an old dirty finish, their first thought is to remove it. In some cases this is the best approach as I will explain below. However, most old finishes do not need to be completely removed to restore the appearance of old furniture. Much of the patina on old pieces is on the outer surface of the wood under the finish and is the result of exposure to sun and air. The chemicals in most strippers "pull out" some of this patina which can affect the desirable characteristics of an old piece. Strippers can also affect the glue in joints and loosen veneer. Museums and conservators of antique and historically important furniture rarely remove a finish and will only do so when the finish has degraded to the point that the stability of the piece is jeopardized. Most of the time, the finish is partially removed which involves the removal of the damaged surface layer only. Almost all techniques involve some type of cleaning and removal of accumulations of dirt, oils, and old polishes from years of use.

Since many of the pieces that come into my shop are antiques, most of the work that we do centers on saving the original finish. While some techniques call for specialized solvents and chemicals, there are several techniques for cleaning and restoring an old finish to the point where the piece once again looks good. My background in conservation has taught me several cleaning and conservation techniques that can be used by most woodworkers to restore a piece of furniture without stripping the finish. In this article, I'll detail several of these techniques that can be done by most woodworkers with a minimum of specialized materials. Before we start, I'd like to discuss those finishes which shouldn't be saved.

 

FINISHES THAT CAN'T BE SAVED

Page 24: Fur restoration

Not all old finishes can be saved. Finishes that are severely damaged or degraded to the point where they can no longer effectively do a good job of protecting the wood should be removed. Although most conservators would like to save the original finish when possible, finishes that have degraded to the point where the wood is in jeopardy should be removed. These situations include severe water or heat damage, large losses of the finish where the wood is exposed and situations where the finish is severely discolored. Another finish that cannot be saved is a finish that is sticky. Sticky finishes are those that have become chemically altered to the point where they will never fully harden. Severe water or heat damage appear as large white areas where the finish is peeling or flaking off. Large exposed areas of wood are very difficult to blend in without highly developed skills so removal of the entire finish is called for. Another problem finish is one in which the finish has been mixed with pigment and applied thickly. Old varnishes and shellacs applied in this manner may develop large cracks or "islands" which show the bare wood below. This finish should be removed in most cases. An exception are crazed or cracked finishes where the cracks do not go all the way through to the wood below. I'll explain how to deal with this later.

The goal in restoring an old finish is not to make it look brand new. At best this treatment should restore as much of the original condition as possible and prevent further deterioration. While by no means is restoring a finish a "quick-fix" type of repair, on most pieces it should be less time-consuming and expensive than a complete stripping and refinishing. In addition, you do not run the risk of ruining the value of an old piece of furniture by removing a piece of its history. The following are the steps in saving an old finish. Sealing damage, cleaning, abrading the old finish (if necessary) and finally waxing.

 

SEALING DAMAGE

 

Damage that needs to be sealed are dents, scratches and small areas of finish that have been worn away. The cleaning process involves water and solvents that could possibly affect bare wood and it should be protected. For sealing, I use a 2 lb. cut light-colored shellac. Using a red-sable artist's brush, I brush several light coats of shellac to the damaged area and then let the shellac dry overnight. Do not try to match the color to the surrounding finish at this point. The cleaning will lighten up the color so blending in at this point will result in a mismatch.

 

CLEANING

Page 25: Fur restoration

Before cleaning, it helps to know what the finish is so that the appropriate cleaners can be used. I test the finish by a three step process using various solvents. Find an inconspicuous spot such as behind a leg and dab a little denatured ethyl alcohol on the finish with a small brush or cotton swab. After thirty seconds tap the area with your finger - if it's sticky the finish is shellac. If the alcohol doesn't affect the finish try a little lacquer thinner. If the finish still isn't sticky, it is probably an oil-based varnish or polyurethane. Knowing which finish you have minimizes possible damage from cleaning solvents as we will see later.

Cleaning is a two step process which removes both water-soluble and oil-soluble dirt and grime. The first cleaning step uses a hydrocarbon based cleaner like mineral spirits or Stoddard solvent. I prefer to use VM&P Naphtha rather than mineral spirits because it flashes or evaporates much quicker. It's important to test a small amount of the cleaner on an inconspicuous area. Certain oil-based finishes varnishes can irreversibly whiten on exposure to some hydrocarbons so testing is crucial and it's important to know what the finish is. Oil finishes may soften and be completely removed, but in most cases VM&P Naphtha has proved the best all-around solvent in my use. Dampen a clean cloth with the Naphtha and rub a small surface at a time. Do not saturate the surface. Switch to clean cloths frequently.

The next step involves using a detergent mixed with distilled water. I use Triton X –100. This is an extremely concentrated non-ionic detergent. I use a 3% solution by volume. An alternative to Triton is Dawn - a commercial dish-washing detergent that is readily available. I use a solution of one capful in a pint of luke-warm water. Apply the solution with a dampened clean cloth, (not dripping wet) and rub a small area at a time. The Triton works very quickly while the Dawn may work a little slower. You'll see your progress by the dirt on the rag, so change the surface frequently. Afterwards, wipe all the excess detergent off with clean water and proceed to the next step.

 

ABRADING

The cleaning above removes the surface dirt from the finish but it still may be hazy or whitish. Part of this problem may be from small crazing or cracks in the finish which reflect light - making the surface appear dull. If this is the case and the cracks do not go all the way through to the wood, abrading part of the finish will remove most of the cracks. I use stearated sandpaper, (sandpaper mixed with zinc stearate to minimize clogging), to abrade away a portion of the finish. I start with 240 grit and proceed to 320 grit and finally 400 grit. I back the paper with a felt or cork block and avoid the edges since it's easy to cut completely through the finish. I strongly recommend wearing a dust mask since the dust is irritating. Sand in straight lines with the finish and wipe the residue off frequently with a Naphtha dampened rag. You can stop sanding when the grain of the wood

Page 26: Fur restoration

is visible or when the cracks have disappeared. Patience is required because a heavy hand will cut through the finish and you'll have no choice but to strip at that point. Wipe the piece with Naphtha and let dry overnight.

 

WAXING

The piece is now ready for the final step. I prefer to wax and buff out, but if you want, you can apply a light coat of whatever finish you prefer. Shellac or varnish will both work over most finishes but shellac should be used if the piece is an antique. I would avoid polyurethane because it will not bond very well to an old finish. Either way, you may need to do a little touch-up first. There may be small areas where the finish is removed down to the bare wood. These should be sealed with several coats of a 2 lb. cut shellac applied with an artist's brush or a small varnish brush. After drying these, areas can be blended into the surrounding area using shellac mixed with dry artists pigments. After drying, seal all repaired areas again with a 2 lb. cut shellac.

For the final waxing, I prefer a good quality furniture wax like Briwax, Behlen, or Antiquax. All these waxes come in clear and dark brown, and Briwax has golden oak, red mahogany and light brown. I prefer the colored waxes because any wax that lodges in crevices or small defects will not be noticeable when dry. Put a scoop of wax inside a clean cloth and apply the wax in a small circular motion. On turned areas, carvings and other irregular areas, work the wax in with a stiff bristle brush. Work on a manageable area at a time and when the wax hazes buff it out using a clean cloth. After drying overnight, give it a second waxing.

When the second coat dries you'll have a restored finish without the bother or hassle of stripping. You'll find it's much less work and the result is that you haven't possibly detracted from the value if the piece is an antique. As an added bonus, you find that the entire process can be done in one weekend, rather than two or three weekends. And finally, the piece will have retained the patina that took so long to acquire with time. And the time you saved can be spent admiring your furniture.

Page 27: Fur restoration

Finish Removal on Wood FurnitureThe Correct Use of Paint Removers or Stripper

Directions for HAND Stripping.

* Work with plenty of ventilation, safety goggles or glases, and skin protection.Stay out of the direct sun and stay protected from wind or strong drafts if working outside.

* Work in small areas starting at the top and working to the bottom of the piece. Apply a generous coat of gel remover. Brush on in one direction. Do not brush back and forth.

* Use soft wood scrapers and/or Steel Wool to remove crinkled finish and spent stripper. Repeat the above process until all layers of old finish are gone. On fine work, when the piece has all the finish gone and looks ready to refinish, go over it again with one last coat of stripper carefully working from top to bottom and removing stripper with Liberon #00 steel wool to ensure all traces of finish are lifted from the pores of the wood. Neutralize the wood surface by washing the piece down with Naphtha followed by Lacquer Thinner, if the piece is newer and in very good condition, a washdown with Lacquer Thinner may suffice.

* Let the stripped piece dry thoroughly for at least 24 hours to 48 hours for softer woods or pieces that required long soaking to clean off all the finish. Refinish promptly to seal and protect from humidity changes and environmental contamination.

HINTS & TIPS:

* Test to see if a through cleaning with Liberon's Wood Cleaner & Wax remover might eliminate the need to totally strip and refinish the piece.

* Use the right stripper for the finish being removed. (Determine finish type with solvents.)

* Use solvent washable strippers or paint removers.

* Avoid water washable removers to minimize grain raising, staining problems, and softening of glues or adhesives and the subsequent lifting of veneers and loosening of joinery.

* Avoid Metal Scrapers of any kind, wood fibers softened from the remover are easily compressed by hard metal edges. These sometimes apparently invisible `indents' can later show up after staining or even under clear coat finishes.

Page 28: Fur restoration

* DO NOT Sand a stripped surface. Sanding removes oxidized fibres, the natural distressing wear and ageing collectors refer to as patina. Upon refinishing uneven and splotchy effects result from the `windows' sanded into the surface. Often sanded areas of stripped wood will not take stain or finish the same as the unsanded part of the same piece. Therefore, for instance, sanding of a table leaf usually means sanding the entire top and remaining leaves. The surface was carefully prepared for the previous finish. Successful refinishing will be much easier if we disturb the wood the very least possible, in the finish removal process.

If an area is badly damaged as to require sanding; proceed with care and be aware of the increased finish work that can be created by sanding. Lightly raised grain can in some cases be stained, sealed with sanding sealer, and then sanded instead of sanding on the bare wood.

* Partially strip (on Lacquers): On some pieces a top for instance might be all that really needs to be stripped and totally refinished. Proper cleaning and touch-up of dings, dents, and blemishes on sides or underpinnings with an over finish of the existing finish might give a very professional result. In the right instance this can be a more profitable for the finisher and offer an affordable option for the customer.

* Use wax paper laid over the remover to slow evaporation and prolong working time. On difficult finishes and in drafty work areas each application of remover can then do more work.

* To lift paint or finish retained in the grain of open pored timber, despite repeated applications of remover, try the following. Let the surface dry for a day, apply a liberal coat of 1 pound cut shellac & and allow to dry throughly then try a coat of remover to lift the shellac and the adhered finish out of the pores. The wax paper trick above helps here also. On hard cases repeat the shellac and remover steps above if positive results come from the first application.

Refinishing

Stripped surfaces are always a little more problematic than finishing on new wood. Generally Pigment Wiping Stains are the best choice for coloring on the stripped surface. Lacquer shading stains and lacquer colorants blended into sanding sealer and build coats are a good bet for color correcting. Use amber lacquer on medium to darker woods or stains to give a richer and homogeneous continuity to the piece. On very light timber and on light colors use water -white lacquer or for the very clearest non-yellowing finish use CAB-Acrylic lacquer.

IMPORTANT:

PROTECT EYES and SKIN.

Page 29: Fur restoration

Always test products in an inconspicuous place to check compatibility and end results.

Companion Materials & Supplies:* Safety Glasses or face shield for eye protection.* Heavy duty rubber stripping gloves.* Apron; preferably rubber or rubber coated.

* WOODEN scrapers(NOT putty knives or metal scrapers)* Stripping BRUSH: stripper resistant plastic for getting into carvings and mouldig.

* STEEL WOOL:#0 or #1 for light clear finishes, #1 or #2 for paints, &#3 or #4 for very heavy built up layers of finish.* Rags.

PRECAUTION:

Do not leave impregnated rags wadded or stacked in bundles as these can burst into spontaneous fire.

Dispose of rags and waste in accordance with local regulations; or lay rags out flat preferably outside, to dry so as to avoid any fire hazard.