SPLITS AND CRACKS IN WOOD
Splits and cracks in wood are ruptures or separations in the grain of the wood which reduce the quality as measured by appearance, strength, or utility. Many people assume that all splits and cracks in wood are caused by the dry kiln or the drying operations. Thus, these wood failures are assumed to be the responsibility (or fault) of the kiln operator. In fact, there are four categories or origins for splits and cracks in wood:
Changing Moisture Content Based
Proper identification regarding the cause of the splits and cracks is critical if the appropriate corrective action is to be taken to actually solve the problem. A wrong diagnosis insures a wrong course of action and thus, a continuation of the problem.
RESOURCE BASED SPLITS AND CRACKS
These are ruptures in the wood that occur in the standing tree or in the log. They are usually the result of various factors such as site or environmental conditions, growth stresses, or the activities of various microorganisms. The names applied to these various splits and cracks vary widely. In some cases, the same name may be applied to different defects, while in other situations, the same defect may have many different names.
One of the more typical ruptures of this type is called ring shake (also known as cup shake or wind shake). Ring shake is a longitudinal separation of wood fibers in the tangential direction, that is, the rupture runs parallel to the growth rings. Figures 1 and 2 are wood components exhibiting ring shake. Ring shakes can be so fine that they are not visible in green logs or lumber. They may only become visible after drying. The occurrence of ring shake in the standing tree has been related to numerous factors depending upon the species and conditions. Some of the major factors are as follows:
Bacteria - Wetwood - Microorganisms
Site and Environmental Conditions
Wood Structure and Chemical Composition
For some species, conditions such as large, overmatured timber; excessive crook or sweep; or poor site conditions are important factors regarding the formation of ring shake. In other species, it may associated with wounds, injuries, or disease.
still other species such as oaks, it may be related to the action of microorganisms especially bacteria.
The important point is that ring shake is a wood quality condition not a drying defect. The split or crack did not originate in the dry kiln or the drying process. Instead, it originated in the standing tree. It is also important to note that shake may not be easily detected in green logs and lumber. It may only become apparent after drying.
PROCESSING BASED SPLITS AND CRACKS
Processing based splits and cracks are those that arise from the conversion of rough, green lumber into finished products. The two major areas of processing based wood failures are (1) drying related damage and (2) machining related damage.
Machining Related Damage
The major splitting or rupturing of the wood that happens during machining is called loosened grain. It usually occurs in moulders and planers, but may also happen in other machines that use rotating knives. It is more likely to occur on the pith side of flatsawn lumber or wood components than on the bark side of the material.
Loosened grain is an actual separation of the wood along the growth ring on the surface of the wood. It has a shelling appearance. This rupturing is the result of the denser latewood part of the growth ring being pounded or pushed into the softer earlywood underneath. The earlywood is crushed and ruptured. A slight decrease in surface moisture after machining will aggravate the defect. Loosened grain can occur in softwoods and ring porous hardwoods .
Loosened grain is caused by the pounding action of dull knives, knives with too small a clearance angle, or excessively jointed knives. Excessive pressure by certain machine parts such as feed rolls, pressure bar, or chip breaker can also cause this cracking in the wood. As mentioned above, a slight decrease in surface moisture after machining will cause the damage to be more apparent.
It is important to note that loosened grain, like ring shake, is a rupture in the tangential direction (parallel to the growth ring).
Drying Related Damage
The types of splits and cracks that occur during lumber drying fall into three major categories:
End Checks or Splits
Internal Checking or Honeycomb
What sets apart the splits and cracks caused by drying from either shake or loosened grain is the fact that drying ruptures occur in the radial direction
In all drying defects (surface checks, internal checking, and end checking) the rupture will extend across one or more growth rings. In shake and loosened grain, the ruptures extend parallel to the growth ring.
CHANGING MOISTURE CONTENT BASED SPLITS AND CRACKS
Splits and cracks in wood that occur due to changing moisture content (MC) can be grouped into three classes:
Environment Drier than the MC to which the Lumber Was Dried Environment Wetter than the MC to which the Lumber Was Dried
Environment means the conditions to which the wood was exposed (1) in the processing plant, (2) in all storage areas, (3) during shipment, or (4) in final use of finished products.
The classic end splits in edged glued panels. This occurs when the equilibrium moisture content (EMC) of the environment to which the panels were exposed was lower (drier) than the moisture content of the wood in the panels. When this happens, the wood starts to lose moisture. Since water moves through the end grain much faster than through the sides and faces, the ends begin drying quickly and try to shrink. The ends are restrained from shrinking by the rest of the panel, thus tension stresses are set up in the ends. If the stresses exceed the strength of the wood or the glue lines, a split will occur. If the glue lines are very good and the wood is of light to moderate density, the split will occur in the wood. If the glue lines are only marginal in strength and the wood is heavy and dense, the split will usually occur in the glueline. In any case, the splits will occur in the weakest spots at the ends of the panel. Splits like these are similar to the splits and cracks that occur in drying, however, they are caused by an imbalance between the MC of the wood and the EMC of the environment. If the EMC of the environment is about two percent lower that the MC of the wood, the potential for this problem exists. This condition is somewhat species dependent, as some woods are more forgiving than others. However, the risk of end splits in panels occurs when the difference between the EMC of the environment and the MC of the wood exceeds two percent. The greater the difference, the greater the risk.
USE BASED SPLITS AND CRACKS
Split and cracks that occur in use usually result from one of two major reasons:
Mechanical Damage (during handling, transporting, erecting, or installing)
Many times, panels or other wood products are dropped, banged, or in other ways damaged during their handling, transporting, or installing. These damages, many times, look like splits or cracks in the grain of the wood. a split in a door due to dropping and other rough handling. Often, the splits and cracks that result from mechanical damage will run at various angles to the growth rings or they will rupture the grain in a more jagged or ragged manner.
In some cases, a wood product is designed and installed in such a manner that it is restrained from the normal shrinking and swelling that accompanies changes in relative humidity. When this happens, the panel or product will develop splits or cracks for much the same reasons that they occur in edge-glued panels. However, in the case of restrained panels, the splits are usually much more severe.
All splits and cracks in wood are not the result of the drying process or the dry kiln. It is important to properly examine and analyze the split and crack to see what was the actual cause. One important rule to remember is that splits and cracks caused by drying extend across one or more growth rings (radial direction). Many other ruptures extend parallel to the growth ring or, as in the case of mechanical damage, run at various angles to the grain and growth rings.
You may have a piece of furniture that is soiled, slightly scratched and worn, but not damaged badly enough to require stripping and refinishing. You may own a valuable antique whose beauty might be enhanced but whose quality could be greatly diminished if you stripped the old finish away, or did anything more than dust the piece. You may own a piece of furniture that really needs some attention but your time or personal situation may not allow you to refinish it just now. What to
do—cleanit and/or recondition it? Cleaning and reconditioning may accomplish the task or will temporarily solve the problem until you can do a more thorough refinishing.
Some methods for cleaning and reconditioning are:
They are listed in order of increasing difficulty. Use the method that will require the least work to accomplish the desired result.
CLEANING AND WASHING
There is no best way to clean a finish. It depends on the kind of dirt. NOTE: Use a water wash
sparingly—watercan loosen old glues.
1.Hot Wash: Add to each gallon of hot water: 2 tablespoons gum turpentine
4 tablespoons boiled linseed oil
This formula works best if it is hot enough to require that you wear rubber gloves. Wring out a soft clean cloth in the solution and wash the wood. The turpentine and hot water will clean away soil, oils, and built up waxes and polishes. The linseed oil will replace oils and actually “finish” worn or bare spots. (Linseed oil has been one of the most used finishes of the past.)
1.Wipe dry and buff with a clean soft cloth. This may be sufficient. Polish with lemon oil or apply a surface wax if desired. This wash works well for furniture, cabinets and wall paneling. Murphy’s oil soap or similar products can also be used to wash wood.
2.Ammonia wash. Make a solution of 20 percent household ammonia and 80 percent water. Wring clean rag and wipe furniture. Depending on the type of finish, this method may discolor or cloud the wood finish.
3.Mineral spirits wash. Moisten a clean soft cloth with paint thinner (mineral spirits) and rub soiled wood to dissolve polish, wax, oil and greasy grime.
Wax build up, finger prints, soil or scratches may require you to use an abrasion technique. Good furniture finishes are actually thick enough that you can “wear” away damage that is on the finish and has not penetrated to the wood. Sometimes the damage is only in the wax or furniture polish that is on top of the finish. A white ring is an example. It may be in the wax or polish or in the finish. Stains that are dark or black are usually through the finish and into the wood. However, the abrasion of the finish will take a high gloss finish to a satin finish and so the abrasion will need to be over the entire surface of the wood.
1.Oil and Abrasive Polish New motor oil OR Paraffin oil OR
Boiled linseed oil
Pumice or rotten stone or whiting (abrasive)
0000 steel wool
Place abrasive in a small can or jar. Place oil in a small can or jar. Dip a small pad of 0000 steel wool into the oil and then into the abrasive. Polish the furniture in small sections, rub back and forth with the grain. Adjust the pressure to the needs of the job at hand When the defects have been removed or sufficiently repaired, wipe off the surface. Polish with lemon oil or wax with a quality wax if desired.
If the piece of furniture has years of polish and wax built up you may want to wipe it off with paint thinner applied liberally to a soft clean rag before you begin the abrasion process.
2.Turpentine and Linseed Oil 1/4 cup gum turpentine 3/4 cup boiled linseed oil
0000 steel wool
Place turpentine and oil in a glass jar. Cover with a tight lid. Shake well before using. When ready to use, put hot water in a small can or jar. Pour some of the mixture on top. Dip a pad of steel wool into the mixture and rub the wood surface back and forth with the grain. When the task is completed, polish with a clean soft rag.
3. Toothpaste and Soft Cloth or 0000 Steel Wool
For small or simple white spots, try toothpaste. Put a small amount of toothpaste on a clean cotton cloth or 0000 steel wool. Buff carefully with the grain of the wood. Wipe off with a clean cloth and oil or wax the surface.
In some cases the wood may be in good shape but the finish may be worn out and thin with not enough left to repair by the abrasion technique. Over coating is the technique of applying a new finish over old.
Begin by cleaning the surface with paint thinner or a weak solution of ammonia and water to remove soil, polishes and waxes. If the stain is worn, apply new stain. In some cases, a coat or two of oil based stain buffed into the wood with 0000 steel wool and wiped with a clean cloth is enough finish.
If stain has been applied, let it dry thoroughly. Apply a thin coat of a clear finish. It is best if you apply the same kind of finish that was used originally, i.e., shellac over shellac or varnish over varnish, etc. The least successful method is any synthetic varnish over shellac. The most successful is penetrating oil/resins over oil/resin finish.
Always test a small amount of finish over a hidden part of the furniture.
If a surface finish has been applied (not a penetrating oil finish) when it is thoroughly dry, wipe it with very fine steel wool and apply paste wax.
Reamalgamation is a process in which the damaged finish on wood is dissolved with a solvent for the original finish and then reapplied as the finish. If this process is well done it will be beautiful. It does not destroy the “patina” of the wood that has come with age, care and use and is often prized.
First you must determine what the finish is because the correct solvent must be used to dissolve the finish. Test solvents in a hidden place. Finishes will dissolve in their own solvent.
If the furniture was built before 1920
and has its original finish, it’s
probably finished with shellac.
Used on commercially made furniture because it dries so rapidly
Not usually found unless the piece was custom or handmade or previously refinished.
This finish will probably never need to be reamalgamated because it is so easily and effectively over coated.
(See previous section.)
Difficult to dissolve. Try lacquer thinner or commercial stripper.
Lacquer thinner or commercial stripper.
For any method, clean the furniture with paint thinner or turpentine. Begin reamalgamation by dipping steel wool or a brush into the appropriate solvent and applying it to the wood surface. Get the surface wet as quickly as possible before solvent evaporates. Brush and/or rub and reapply solvent until all defects disappear. Apply more solvent to the finish and smooth the reamalgamated surface with long light strokes, working with the grain. When the surface is dry, buff it with 0000 steel wool to remove any rough spots. Apply a good paste wax. It should look like new.
There are some “amalgamators” on the market which are solvents for most finishes. The Mohawk Company has one called “Amalgamator.” Formsby’s is called “Furniture Refinisher.” There are several other brands available. Polyurethane finishes cannot be reamalgamated.
This method is often used by professionals to repair valuable furniture and is called “French Polishing.” Padding is a technique in which a new finish is applied over an old one using a tightly rolled pad of soft cotton cloth and “padding lacquer” such as
Pad-Lacavailable in Constantines Wood Workers catalog.
Make sure the wood is clean. Prepare the padding cloth by rolling a soft clean piece of cloth fabric large enough to fit in your hand. Dip the pad into a bowl of padding lacquer and squeeze it to remove any excess liquid.
Stroke the damaged surface with a moistened pad, using small up and down rocking motion with your hand and wrist. The padding cloth must be kept moving because the solvents in “padding lacquer” dry so quickly that a resting pad will leave impressions of the fabric on the wood. Start padding motions gently to wet the surface and then increase pressure to generate heat that will help lacquer dry. Continue adding padding lacquer to the cloth and move around the project until finished. Rub the wood surface with the pad for at least 15 minutes to make sure lacquer is dry.
The padding finish will be quite glossy. If you desire a dull finish, or one with less shine, rub with 0000 steel wool and apply paste wax.
Patching is used to repair large scratches, gouges, burns, etc., in the surface. This method is often used when there is a surface blemish on an otherwise undamaged finish.
If shellac sticks are not available in your local paint or hardware store, they may be purchased from mail order supply firms. You will want to practice the technique on a wood scrap before repairing furniture.
Shellac sticks in color of wood
Alcohol lamp or some way to heat spatula and shellac stick Artists spatula or grapefruit knife
400 grit waterproof abrasive paper Paraffin rubbing oil (car oil will do)
Heat the spatula and the tip of the shellac stick. Apply the melted shellac to damage area and smear into place with spatula. If shellac cools too fast, reheat spatula and smooth shellac.
When damage has been repaired and shellac has cooled, shave off excess with sharp razor blade. Sand with 400 grit paper lubricated with the oil. Touch up the spot with padding lacquer.
2. Wax Stick Patching
Wax sticks are readily available and come in many colors. (I have even used crayons and they work well.) Colors can be blended.
Spatula or knife
A heating source to melt stick. (There are special refinishers hot patching knives available.)
Heat wax and let it drip into damaged area. Leave slight excess rounded on top. Use a hot spatula blade to work into blemish and to make it even with surrounding surface. If necessary, smooth it up with the razor blade.
If the repaired area will receive any wear, cover it first with a coat of shellac, which makes it possible for other finishes to adhere, and then a coat of varnish or lacquer.
COMMON SPOTS, DEFECTS AND POSSIBLE CURES
1. White Spots, Rings, and Blushing
White spots are caused from moisture damaging the polish or wax layer of the finish. Some finishes can turn white just from moisture in the air. (This will not happen in most of arid Utah.) The whiter the area, the deeper into the finish the moisture penetration.
Cure: Choose an abrasion cure, one of these will cure most white spots and rings. Apply wax or polish with lemon oil.
2. Dark Spots and Rings
Dark spots are more serious than white spots and indicate water has penetrated into the wood. This kind of damage does not happen in a short time. It has probably been caused by a flower pot or something very moist being left on the wood for several days.
The damaged area will probably need to be stripped, the stain bleached with oxalic acid and refinished. If the whole piece of furniture does not require refinishing, be sure to protect it very carefully while you repair the damage. Repair the whole surface where the damage is found (i.e., table top, etc.). If you attempt to repair only the spot you will be left with a larger damaged spot. This can be true of all repair methods. NOTE: If you cannot find oxalic acid at the hardware store, try the drug store. It comes in crystals which are dissolved in warm water for use.
If oxalic acid doesn’t remove the stain, you may try household bleach, or a two solution wood bleach found at the hardware store.
Two-partwood bleach will take all color from wood, so be very careful. Some sources say oxalic acid is very dangerous, others say it is mild and safe.
On raw wood (stripped or unfinished wood) dents are easily removed by holding a hot iron over a damp cloth which has been placed on the dent. Wool fabric works very well because it holds lots of moisture without dripping or running. The steaming fills the wood fibers and causes them to swell and fill the dent. Steam as long as necessary to fill the hole. The fibers will usually swell a little above the surface. It is very important to let the raised wood dry thoroughly before sanding or the entire bruised area may come out. On finished furniture, you may have to remove some of the finish or puncture damaged area with pins to allow the penetration of steam.
Repair finish by over coating, reamalgamation or padding.
Scratches and Hairline Cracks
1.Small scratches and
cracks—tryone of the following:
a.Rub with a walnut meat.
b.Rub with Old English or similar stain filled furniture polish.
c.Rub with matching color shoe polish.
d.Rub with matching oil base wood stain.
e.Paint with matching crayon.
f.Paint with matching color felt tipped pen.
2.Alligatoring and hairline
cracks—usuallycaused by swelling and shrinking of finish:
a.Reamalgamate the finish.
b.Repair polyurethane finish by over coating with another varnish.
c.Buff in a coat of matching stain using 0000 steel wool.
3.Deep scratches, missing wood.
a.Use a patching method.
Scars, Gouges, Burns
If the damage is caused by burning, scrape all of the burned area away before patching. 2. Remove old finish and refinish the wood.
Worn and Thin Finishes
Clean. If the stain is also worn away, restain to match surrounding area, and overcoat with a new finish.
Abused, Worn and Scratched
Try repairing with padding technique. 2. Complete refinishing.
Remember to assess the soil, spot or damage and use the simplest and easiest method that will accomplish the task.
Follow cleaning method with a rub down of good quality lemon oil polish (available in many brands) or wax.
Work safely. Use protective gloves and eye glasses when using any chemical or method to clean or repair wood. Be sure to work in a
SOURCES USED FOR CLEANING AND REPAIRING OUTLINE
1.Furniture Finishing and Refinishing. Sun Set Books, Lave Publishing Co., Menlo Park, Calif.
Furniture and cabinetmakers often apply a very thin layer of hardwood (veneer) over a less- expensive base material. On occasion, the glue bonding the veneer to the substrate can fail, causing it to delaminate at the edge or bubble (blister) in the interior; or the veneer can be damaged enough to require a patch. You can usually make these repairs yourself. Purchase wood veneer at craft stores and through woodworking mail-order catalogs. (We recommend that you have a particularly valuable piece repaired by an experienced professional.) Here are the basics for repairing damaged veneers.
- Very thin, sharp blade
- Block of wood and weight
- Flat metal ruler or other straightedge
- Thin paper (tracing paper)
- Hair dryer or household iron
- # 2 lead pencil
- Brown paper bags or Kraft paper
- Matching veneer
- Veneer roller or wallpaper seam roller
- Cutting board
- Matte knife or very sharp wood chisel
- 120- and 220-grit sandpaper
- Artist's palette knife
- C clamps
- Yellow carpenter's glue
- Stain and finish with appropriate applicators and solvents
- Wax paper
- Artist's paintbrush and oil paints (optional)
- Tip: This project requires that you make very sharp cuts into veneer, but even the sharpest matte knife or single-edge razor can damage it. For best results use a scalpel (available by special order from pharmacies) or a double-edge razor blade, which is thinner and sharper than a single-edge razor. To stiffen the blade and cover the unused edge, sandwich and glue the blade between two small, thin pieces of wood or wrap all but one edge of the blade with numerous layers of tape.
To Fix a Veneer Blister or Bubble
- Try to Reactivate the Glue: If the furniture is old, the glue may be reactivated with heat. To do this, use a very sharp, thin blade to cut a straight slit through the veneer in the direction of the grain from one edge of the bubble to the other. Then heat the surface with a hairdryer, or place several layers of brown Kraft paper (paper bags) over the area and use a household iron. When the glue is softened, immediately roll the area with a veneer roller or wallpaper seam roller.
Tip: To avoid overheating and softening nearby well-adhered areas, heat a little at a time and press-and-release the veneer to test whether the glue has become tacky.
- Reglue the Veneer: If the heat doesn't work (and it won't on modern glues), use a very sharp, thin blade to slit an elongated X through the veneer as much in line with the grain as possible. Then scrape as much old glue as possible off the substrate and the back of the veneer using a
matte knife or very sharp wood chisel. Use an artist's pallet knife or similar tool to apply yellow wood glue between the veneer and the substrate. Roll the surface with a veneer roller or a wallpaper seam roller. Wipe off excess glue with a damp cloth. Cover the area with wax paper, a block of wood, and a heavyweight for at least one hour.
- Tip: These same two steps can be used to rebond veneer that has delaminated at an edge, except that it is not necessary to slit the veneer.
To Patch Damaged Veneer
- Cut out the Damaged Veneer: Use a matte knife (with a brand-new blade) guided by a metal ruler to make an elongated diamond-shaped cutout in the veneer around the damaged area. The patch will blend with the grain and figure of the wood better if you avoid making cuts across the grain, so cut so that the long points of the diamond are in line with the direction of the grain.
- Remove Veneer and Old Glue: Remove the veneer inside the scored diamond using a matte knife and/or a very sharp wood chisel, beveled side facing down. Scrape off all the old glue to the bare wood.
- Trace the Patch: Lay a piece of tracing paper over the cutout and lightly rub the perimeter with the side of a soft pencil. Tape a piece of matching wood veneer to a cutting board and tape the tracing paper over the veneer.
- Tip: Compare and match as closely as possible the wood grain and figure of the area to be patched with that of the veneer patch.
- Cut the Patch: Use a very sharp, thin blade (such as a matte knife) guided by a metal ruler to simultaneously cut through the paper and replacement veneer. Test the fit and, if necessary, carefully reduce the edges by sanding with the grain against fine sandpaper on a hard, flat surface. Be very careful. The veneer will be delicate, especially at the points.
- Install the Patch: Brush a thin coat of yellow wood glue on both the surface of the substrate and the backside of the veneer patch. Press the veneer in place with a roller and cover it with a piece of wax paper. Lay a block of wood over the wax paper and apply a C clamp or a heavyweight for about an hour.
- Sand and Finish: Sand the patch until it is perfectly level with the surrounding area and apply stain and finish to match the existing surface.
- Tip: To make the patch even less evident, use an artist's brush and oil paints or permanent markers to extend grain lines from
the surrounding area into the patch (or vice versa) before applying a finish.
Old Furniture Masters
The old furniture masters all used the thinly sliced wood to add natural beauty to their already fantastically crafted furniture. You probably would never find a Duncan Phyfe cabinet or table that wasn't veneered. Duncan Phyfe preferred to work with Mahogony. He would make a furniture piece out of solid Mahogony, then veneer it with Mahogony. He preferred the rich beauty and natural art that isn't available in solid wood. Many other well-known furniture makers did the same thing, making furniture from a particular type of wood, then veneered with the same type.
Lots of other furniture makers used whatever kind of wood was locally available to hold down cost, then veneered for the prettier appearance. It's impossible to find the delicate swirls, sprays, and rays in solid wood that you will find in veneer.
A table that has a top with a repeat design or a design with a mirror image beside it is without a doubt veneer. The mirror image is from slicing wood thinly then opening it like a book.
The thin wood overlay is fragile in its natural state because it's generally only 1/64 inch thick, but when it's properly glued to another surface it becomes a part of that surface and has considerable strength. You have to be careful when sanding because it is so thin you can sand right through it, but it doesn't take much sanding to smooth it, because it is sliced with an extremely sharp knife.
Lumber manufacturers have taken pity on us and have made a product that is so easy to use that even the die-hard furniture purists use it.
Veneering used to be only for the master craftsman and the stout of heart, but now modern technology has made it simple for even the timidest. They've glued a thin sheet of paper to the back to keep the thin wood from being unruly, making it possible to cut very evenly so that edges may be joined easily, then they put some very sticky glue on the paper and a protective sheet over the glue, so all you do is pull the protective sheet loose along an edge for a short distance, position the edge and carefully press it to hold it in place and remove the rest of the protective sheet.
Working from the center toward the outer edges with a roller or blade press the veneer tightly to the surface, then finish as you would any wood.
Repair Damaged Veneer
Problem: Many antiques are covered in a layer of wood called a veneer, but the beauty and value of these antiques can be reduced by damage to the wood veneer.
Solution: Damaged areas can sometimes be repaired, restoring the beauty and value of the furniture.
Cut out the damaged area with a utility knife.
- Gently cut out the damaged veneer along the natural grain as much as possible.
- Try to form a simple shape to replace, such as a triangle.
Make a template of the damaged area.
- Make a template of this shape by placing a piece of paper over the area and rubbing lightly with a pencil until the outline is visible on the paper. (figure B)
- Cut out the template (figure C) to match the damaged area as closely as possible. Put the triangle piece in place to confirm match then trim as necessary. (figure D)
Make a replacement piece of veneer.
- Transfer this shape to a new piece of veneer and cut it out.
- Try to find a piece of veneer with the same grain and texture.
- Sheets of veneer are available from woodworkers' catalogs or specialty stores.
Install the new piece of veneer.
- Swab a little glue onto the damaged area and onto the back of the new veneer.
- Press the new veneer into place.
- Roll the edge of the piece with a seam roller to press into place. (figure E)
- Gently clean off the excess glue with a damp rag.
- If possible, clamp it in place or weigh it down, using a piece of wax paper between the veneer and the clamp to prevent sticking. (figure F)
- If the new veneer happens to be thicker, gently sand it down later.
Procedure for Repairing Buckling or Warped Pieces of Veneer
- Cut or slit the warped area with a utility knife.
- Apply a small amount of glue to a knife blade and work underneath the veneer.
- Press the veneer down, and clean off the excess with a damp rag.
- If possible, clamp into place or weigh down while the glue dries.
- Again, use a piece of wax paper between the veneer and the clamp.
The beauty value of antiques and can be reduced by damage to the wood veneer.
While the above repairs can work on small areas, larger areas or areas with more extensive damage are best repaired by professionals.
Another description of repairing veneer
There is no easy way to go about this. Find a quiet and comfortable desk with very good light. Secure your veneer, a cutting surface (breadboard, cardboard, etc.), x-acto knife (I like the little disposable knives with the “breakoff” blades), metal straightedge, reading glasses, and a high-intensity light. Use your old wood as a pattern for large pieces. Study your new veneer carefully and choose sections that closely match the grain pattern, colour and direction of the old piece. Cut the new veneer carefully with fresh razor blades making multiple light passes until it separates. Cutting slightly oversized pieces is preferable as it allows for slight misalignment errors when gluing. Trimming of excess material is easily done once the glue has dried. Make damn sure you are satisfied with your new veneer pieces after you cut them. Place them over the old wood, step back, and critically evaluate how well they are aligned. If you are not happy, cut another. Once you glue these down, you are committed, so now is the time to make sure you like what you see.
Finding the right glue was a concern. Eventually, I decided to go with contact cement (alternative veneer glues are listed in the “materials” section above). The label directions seemed reassuring, and the other recommended glues were simply not to be found.
Contact cement is thinly applied to both the substrate wood and the veneer with a cheap disposable brush. Be mindful that the application and curing should be done at a moderate ambient temperature. Don’t let your wood sit out in your cold garage before you begin. Both pieces must be absolutely clean and free of dust. After waiting about 10 minutes, the glue is slightly tacky and has a glazed appearance. Don’t be fooled: When these two pieces meet up, they will stick like gangbusters. Next comes the moment of truth. You get one and only one shot at this: carefully align the veneer over the backing wood and when you are sure everything lines up properly, join the pieces. Lay a piece or two of writing paper over the veneer and then, using a small, hard rubber (or plastic) roller and lots of force, roll the veneer in several directions to assure good bonding. Then lay the piece on a flat surface and cover again with a sheet or two of writing paper and a magazine or book and finally, apply evenly distributed weights overnight (I used concrete blocks and water jugs). After the glue has thoroughly dried, remove the weights and admire the result. Next, trim away any excess veneer around the edges and then sand the edges to get a nice smooth and continuous appearance. You needn’t sand the new veneer surface unless you find small imperfections. Just give it a quick once-over with the 1500-grade sandpaper and the Scotchbrite.
If the new veneer is a good overall match to the shade of the older pieces, do not stain it. If however you must darken it a bit, do so carefully! Apply a good walnut shade, water-based stain very lightly with cheesecloth or better yet, a terrycloth wiping pad. Remember that a little goes a long way and it’s best to “sneak up on the correct colour” with multiple light applications of stain. Practice on a test piece and don’t soak the application pad. Be sure to quickly (seconds, not minutes!) wipe of the excess. Do the whole piece at once to get an even application. Continue the process as needed to get a match. Never use a pre-stain wood conditioner! These are supposed to tighten the grain but they also seem to have the ability to attack the glue. (I had a large bubble form under the veneer after applying the conditioner and I very nearly had to start over. Quick work with my handy rubber roller and some weights saved the day.) After staining, you will have to buff the piece lightly with 600 and/or1500- grade sandpaper to knock down the raised grain.
My biggest veneer challenge was in replacing the horizontal surface at the top/center of my dash around the ashtray cavity. This section was missing altogether and although flat, required some complex cutting and was not easy to match to the surrounding wood. Nor did it easily lend itself to the roller and weights necessary to assure a good bond, but eventually,
ingenuity won out. I did cut this piece slightly oversized and I was pleased at how easily I was able to trim and sand it (after the glue dried) to match the contours of the adjoining wood.
Minor repairs to veneer are tricky. They require that you cut small, irregularly shaped pieces of veneer in an iterative fashion until they match the scar you are trying to disguise. Always pick a piece of veneer with the appropriate colour and pattern first. I found that I had to grip the patch with tweezers as I carved it to size and that I had to start over on more than one occasion. Once pleased with the veneer patch, it can be glued, rolled, and lightly sanded to conform to the surrounding veneer. Sometimes a bit of wood filler is necessary to fill small voids. Where colour match is a bit off, you may find it necessary to apply some stain with an artist’s brush or q-tip. If so, apply the stain then wipe off quickly lest you over-darken the work. Continue this process until a good match is achieved. I am told that experienced restores are adept at recreating veneer patterns with paints applied with an artist’s brush. This seemed beyond my skills, so I did not attempt it.
In some pieces, I left deep imperfections, as fixing them would risk the veneer or my sanity. Besides - they add a little romance! For example, I found a deep (through the veneer and into the hardwood below) burn mark on the passenger door jamb trim. It was impossible to completely remove. Rather than re-veneer the entire piece, I opted for cleaning it up as best as possible and letting the polyurethane blend and mute the scar. It’s still visible, but it’s not ugly. One might say that it adds a bit of character or romance.
Application of Polyurethane Finish
Surgical cleanliness was my watchword for the application of polyurethane. I chose my den as a dedicated room for brushwork. I kept the room warm; but hours before I was to apply the finish, I closed all doors and windows and kept the forced air system off to avoid stirring up dust that might settle onto wet surfaces. I NEVER sanded or cleaned my wood in the den, only while in the garage. To further avoid contamination, I frequently changed clothing before doing brushwork – especially after sanding. I only used the best, natural bristle brushes and thoroughly cleaned them in mineral spirits between coats and I often discarded them and used new brushes. Also, do not apply the coating to wood that has not been at room temperature for at least 8 hours.
As stated above, I chose clear, gloss, oil-based polyurethane for its durability, longevity, ease of maintenance, and ease of application. I also came to appreciate that it ultimately serves as a strong glue in that it assures no future de-lamination problems provided you apply some of it to the sides and back of the pieces.
Each coat was left to dry 24 hours in my warm "surgical room". Between coats, I sanded with 1500 sandpaper (600 if a blemish needed to be knocked down) and the Scotchbrite, then cleaned with a damp diaper. Don’t be alarmed or shy when sanding. It appears to irreparably scar the dried polyurethane, but you will find that the next coat “wets away” all traces of the sanding.
I bought my polyurethane in small 8-ounce cans. After the second or third coat, I threw out the first can (this stuff is cheap) as dried product was forming under the lid and I feared
contamination. Always apply the product under a good high-intensity lamp so that you can assure even application and detect missed spots, bubbles, etc. Never shake or stir the product. Using a new or thoroughly clean brush, apply the product in a light and even coat with your final strokes all going in the same direction. A light touch on the final pass should remove any small air bubbles that form on the surface. You will be relieved at how gravity will smooth out brush marks just moments after you finish brushing. After application, lay each piece flat (wet surface parallel to the ground to prevent running) on a clean sheet of newspaper. When each piece has received its coat, retire. Don’t try to go back and brush again a few minutes later as the product will already be setting up, and disturbing it in any way will mar the finish. Fix any blemishes in the next sanding cycle.
Apply as many coats as needed to achieve the look you want. I was satisfied after three or four, depending on the piece. Be patient. Always allow at least 24 hours between coats. If you wait only 4 hours or so, you will find that when you sand the surface, large sticky clumps will roll off the surface (as opposed to a powder) and you’ll have some extensive rework to do.
Wood is dynamic material. Some say that it is still “living” even after it is made into furniture. Unlike composite materials and stone, it is constantly adapting to its environment and actually changing weight, shape and size. For instance, a 42” wide table can change 3/8” of an inch in width over the course of a year as the relative humidity in a living space varies with the seasons. Sometimes one surface of a wooden component will receive a different exposure to seasonal changes than the other side and a slight warping or “cupping” might occur. “Cupping” and warping are minimized by engineering the furniture so that wide expanses of hardwood, such as table tops, are stabilized by other components that run across the width of the panel and limit the extent to which the wider panel can move. We also retard variation in moisture content with the application of moisture resistant Greenguard finishes. While engineering solutions can limit changes in shape they will never totally eliminate them and some movement is to be expected.
Some interesting facts about solid hardwood furniture and how moisture and humidity effect it:
The hardwoods we use to make furniture have been dried to 6% - 8% moisture content.
The equalized moisture content (EMC) of a typical living environment varies from a low of 4% to a high of 11%.
The range in environment humidity impacts the moisture content of everything in it. For example, when a 42” x 84” Axis Dining Table leaves our factory it weighs 120 lbs. 8 lbs, 6 ounces of that is water.
If exposed over a long enough term to the driest residential environment (heated air in a winter climate) it will lose about 3 1/2 lbs. of water. Exposed to a high humidity environment (un-air conditioned beach house) it will gain 3 1/2 lbs. It almost never reaches those extremes, because the driest and most humid seasons usually only last for several months and moisture resistant finished retards drying and uptake of moisture.
Think of the cellular structure of wood as bundles of long narrow tubes. As the moisture content of the cells is reduced the tube shrinks in width but not length. With this variation in moisture content, solid wood furniture shrinks, expands and moves. The movement is small and happens slowly and often time it is never noticed. For each 3% change in moisture content of finished wood the width of the wood will change 1% in its width. That means that if we make a table 42” wide out of lumber that is 8% moisture content, and it is left long enough in an environment with 11% EMC, it could expand by 3?8” in width. In extreme to the other, the change in width would be 3/4”.
Yes, you have heard the right thing. Sagwan wood is much better than ordinary wood, that's why it is used in costly furniture and interiors. This wood is also called teak wood .
The different types of wood in India are legendary for the quality they add to the furniture. Though the styles and structure of furniture's have transformed over time, wood or timber remains the favorite among all the building materials.
The handmade wooden furniture's endurance and high artistic value is well known throughout the world. Wooden furniture has always been a essential element for interior designers. The different types of wood in India which are commonly used for the quality and other properties.
Below table consisting the different types of wood in India and their scientific names
Different Types of Wood and Their Scientific Names
Name Scientific Names Teak ( Sagwan wood ) Tectona Grandis Rose Wood Dalbergia Latifolia Satin Wood Chloroxylon Swietenia Sal Wood Shorea Robusta Sisoo Wood ( Sheesham wood ) Dalbergia Sissoo Marandi Wood Melia Azederach Mahogany Swietenia Macrophylla Mulberry Wood Morus Alba Deodar ( Pine wood ) Cedrus Deodara JackFruit Artocarpus Heterophyllu
Teak (Tectona grandis) is considered to be the best type of wood to make furniture as it is highly fire resistant and durable. Teak is also one of the most expensive woods in India.
It looks very attractive after polishing and will not get affected by white ants and dry rots. It does not shrink much and would not corrode metal fastenings. It is one of the most common types of wood and is for superior use only. It is found in central and southern India.
Advantages of Teak wood :-
Aesthetic Appeal : Furniture made out of teak wood has an attractive looking straight grain pattern. It is smooth to touch and has a rich brown color after polishing in comparison to furniture made out of plywood or particle boards.
Durability : Teak wood furniture can last for up to many years, some have not perished for as long as 200 years. Besides, teak wood doesn't get damaged while shifting places because of water.
Resistant to rot and decay : Furniture made of teak wood is durable and does not rot because of its high density. Good wood furniture should stay in proper shape for a long time.
Teak's high tensile strength and tight grain make it weather resistant and durable. It is used in the manufacture of outdoor furniture and boats. It is also used in indoor finishing's, indoor flooring and for making countertops.
Rosewood : Dalbergia latifolia is tough and very close-grained. It maintains its shape and is available in large sizes which can be used to make ornamental carvings and to create cabinets. It is found in Kerala, Karnataka, Tamil Nadu, and Orissa.
Advantages of Rosewood : -
Hard and Tough : They have high crushing and bending strengths offering good stability to the furniture carved out of it. Among the different types of woods available in the country, rosewood is considered the most attractive.
Attractive Wood Grain : The beautiful grain appearance has led to the creation of many musical instruments and decorative items.
Varied Uses :-
Furniture and cabinets are often constructed out of hardwood like Rosewood. Many mathematical instruments such as rulers and musical instruments such as violins are carved out or rosewood because of its beautiful outward appearance.
Rosewood is used in making kitchen and bedroom cabinets, dining sets, musical instruments, and carvings because of its sturdiness and beauty.
Satin wood or Chloroxylon swietenia is very robust and durable. Its high gloss finish makes it very attractive. It is found in central and southern India. It is robust and durable. Its high gloss finish makes it very attractive. It is found in central and southern India.
Advantages of Satinwood :-
Easy to care : Satinwood gives flawless finish which hides minor imperfections. It is a good choice for laying floors as it will not need everyday cleaning. As opposed to other different types of wood, this is mainly used to make flooring.
Little Maintenance : It asks for regular polishing but does not need daily maintenance. The polished surfaces stay beautiful for a long time.
Durability : It is durable and gives the desired look or finish with a polish of choice. Satinwood is used to manufacture decorative pieces and furniture.
Sal Wood :
Sal Wood or Shorea robusta is primarily found in Uttar Pradesh, Bihar, Madhya Pradesh, and Andhra Pradesh. The tensile strength and durability make it a popular choice for making musical instruments and flooring. It is primarily found in Uttar Pradesh, Bihar, Madhya Pradesh, and Andhra Pradesh. The tensile strength and durability make it a popular choice for making musical instruments and flooring.
Advantages of Sal wood :-
Durable : It is the most durable type of timber making it a popular choice for constructing furniture, wooden beams, and wooden frames.
Immune to Decay : It is resistant to the attack of fungus, white ants and insects.
Strength : Its strength makes it an ideal choice for providing strength and support. Sal wood is used to make doors, piles, and wooden frames. It is also useful in making small pieces of furniture.
Sisso or Sheesham' or 'Tali' (Dalbergia Sisoo):
SissoIt (Dalbergia sissoo) is called 'Shisham' and also 'Tali' in some regions of the country. It is durable and can be easily seasoned. It takes up the rich polish. It is found in Bengal, Assam, Uttar Pradesh, Maharashtra, and Orissa.
Advantages of Sisoo wood :-
Strength : Sisoo is strong and durable.
Good finish : Out of the different types of wood, Sisoo takes up polish very well, therefore, giving a good sheen to the furniture and flooring.
Good look : Furniture or flooring made of Sisoo look attractive, thus making it a valuable investment for your home.
It can be shaped well to make decorative pieces of furniture. It is used to make railway sleepers and sports goods as well.
Marandi Wood or White Cedar (Melia Azederach):
Marandi Wood (Melia Azederach) or White Cedar timber, is resistant to decay and termites. It can be shaped to make wooden accessories. It is mostly imported from Malaysia and is lighter than other types of wood. It is resistant to decay and termites. It can be shaped to make wooden accessories. It is mostly imported from Malaysia and is lighter than other types of wood.
Advantages of Marandi wood :-
Decay resistant : It is impervious to termites, decay and insects.
Good texture : It is light, soft and uniform in texture.
Beauty : Among the different types of wood, Marandi requires less maintenance and its aesthetic appeal is high especially when it is
Marandi wood is used to create wooden accessories like shoe racks, chests, drawers, trunks, and other decorative items.
Mahogany (Swietenia Macrophylla):
Mahagony even stays durable underwater and takes up a deep color after polishing. It is found in Bengal, Assam, and Kerala.
Advantages of Mahogany :-
Glossy Finish : Its pores absorb paint so well that it gives an elegant glossy finish that makes it a perfect choice for making furniture.
Durability : It doesn't decay under water.
Finesse : It is the finest wood, therefore, can be sculpted easily.
Mahogany is used to make cabinets, furniture, and patterns in decorative pieces of art.
Mulberry Wood (Morus alba) :
Mulberry wood or Morus alba, gives a neat finish and can be carved easily to make floors and ornate pieces of furniture and decoration. It gives a neat finish and can be carved easily to make floors and ornate pieces of furniture and decoration.
Advantages of Mulberry :-
Strength : It is tough and elastic.
Clean finish : It makes attractive pieces of furniture because of its aesthetic appeal. Its color range is broad in comparison to other types of wood, which can be used to give a desirable finish.
Can be easily carved : It can be easily worked with and makes ornate pieces of furniture and functional objects like drawers and cabinets.
Mulberry can be used to make small pieces of furniture, turned objects and fence posts.
Deodar (Cedrus deodara) also called Pine wood :
building material, Deodar (Cedrus deodara) is very sturdy, rot-resistant, close-grained and can take up the deep polish to give a good finish. It is found in Punjab and Uttar Pradesh.
Advantages of Deodar :-
Durable : It is long-lasting and sturdy and a fine wood.
Rot Resistant : Deodar is immune to decay by water and insects, giving it a long shelf life.
Absorbs High Polish : It absorbs color in varying degrees which makes it useful in making ornate objects and furniture.
In olden times, it was used to construct religious temples and landscaping. It is used to make railway carriages, railway sleepers, packing boxes and furniture.
Jackwood or Kathal Ki Lakdi (Artocarpus heterophyllu)
Jackwood is compact, finely grained and easy to work with. It is found in Kerala, Tamil Nadu, and Maharashtra.
Advantages of Jackwood :-
Even Grained : It is even grained which gives it a good finish.
Easy to work with : It can be easily carved and designed to create furniture and other articles.
Aesthetic Appeal : The beauty of the wood makes it a popular choice for making musical instruments and aesthetically appealing objects.
Jackwood is used to make furniture, door panels, cabinets and musical instruments.
These are the different types of wood in India used for crafting furniture. As with the woods available in the market today, there also various synthetic alternatives are available nowadays to make furniture but Indian households still prefer solid wood furniture because of their durability and reparability. These advantages of wood make it a popular choice over man-made alternatives of wood. Since Indians prefer furniture and decorative objects with intricate carvings, wood is preferred and certain types of wood like teak ( Sagwan wood ) are popular choices.