The goal of repair work is to make all repaired areas as inconspicuous as possible
Types of glue
- Titebond II Wood Glue (interior and exterior use) It is water resistant, weatherproof, and stainable.
- Elmer’s Carpenter’s Wood Glue (interior use)
- Elmer’s Stainable Wood Glue (interior and exterior use) It is water resistant and stainable.
Gluing can be done at any time:
- Glue before scraping to strengthen wood or secure splintered/ragged end grains.
- Glue during the working process to repair problems areas as they occur.
- Glue in the final stages of sanding to strengthen or secure problem areas that were left to the end.
- If a problem has been left to be glued ‘later’ it may be prudent to cover the area (ends, if broken) so that the edges stay clean. The piece may need to be stabilized that further damage does not occur.
- Test your glue. Some glues will dry yellow or darken the wood. If using a ‘yellow’ glue and it darkens the wood, try using white glue like Elmer’s.
- Wood must be clean, dry, and free of any oils or grease.
Gluing Wet vs. Dry wood:
- When wood gets wet the wood fibers/cells open and expand. Since glue will adhere better to moistened wood the rule of thumb is to spray all surfaces with water before applying glue. However, there are exceptions to this rule. If you have a break in the wood and the wood at the break is splintered ‘fat’ wet fibers may not fit back together snugly and when dry, show an uneven line. In this instance, applying glue to dry wood may be better way to go.
- After applying glue, clean off excess with a moist cloth and try sanding around the area with fine grit sandpaper. Brush the sawdust into the damp glue.
- Sand again after completely dry.
- For very fine wood layers that won’t stay down, you can try using super glue.
- When gluing ragged edges (like the exposed end grain) you can either mix your glue with water (50/50) or really saturate the area to be glued with water before full strength gluing.
- If the wood has warped or fractured and the area to be glued doesn’t fit snugly try using steam to make the wood more pliable.
- Place your wood on a rack, or directly on the rim of a pan of steaming water.
- Let it sit in the steam for a few minutes until the wood becomes flexible enough to be brought back into place.
- Glue and stabilize.
- For smaller pieces use a tuna fish can (top and bottom removed), or equivalent, to support the wood over the steam.
Stabilizing Glued Pieces:
- It is helpful to have an extra pair of hands when you stabilize a glued piece.
- Don’t glue in class unless the wood can be secured and stabilized. The bond can break during the drive home.
- Patience, Patience, Patience – Some glues say they bond in 20 to 30 minutes but it is always recommended to let the glue dry “overnight” before moving.
- If the wood needs to dry at an angle that can’t be achieved with the conventional tools you can try suspending the wood with a weight in the middle.
Tools to use to stabilize your wood while the glue is drying:
- Flexible cohesive bandage (Pet-Flex or Co-Flex by Andover)
- Cut fat rubber band(s) and tie
- Self-fusing splicing tape (found at ACE Hardware) – This tape will fuse, to itself, permanently if left for more than several hours.
- Fine cracks can be filled applying a small amount of glue into the crack and fine sanding over it
- Larger cracks or holes can be filled by using a combination of glue and sawdust.
- Toothpicks, sticks, or course sawdust can be used to pack and fill deep holes.
- Mix together 1/3 wood glue (can use white or clear glue) and very fine sawdust into a stiff paste. (Use sawdust from the immediate area so the color of the ‘fill’ will closely match the surrounding wood.)
- Sawdust should resemble flour. Sawdust can be sifted through a nylon or very fine sieve to get rid of any big chunks.
- Moisten the area to be filled and ‘fill’ the area with the paste. Press hard to completely fill the crack or hole and all air bubbles are eliminated.
- Clean off excess and let dry completely.
- Repeat this process if there is shrinkage after drying.
Strengthening Weak Areas:
- A very thin, strong piece of fabric such as nylon or silk can be used to strengthen an area where the surface has contours or cracks in thin, stand alone areas of the sculpture.
- Cut a strip of fabric and glue to the weak area.
- Rub very fine sawdust into the sticky wet glue. Let dry completely.
- Sand area smooth.
- Fabric is less conspicuous than wood as it is much thinner. However, it is not as strong as wood and should be used accordingly.
- Popsicle sticks or other thin pieces of wood can be glued to the sculpture to strengthen or stabilize problem areas.
- Wood, being much thicker than fabric, can support heaver more “load bearing” parts of a sculpture.
- Wood Hardener (PC Petrifier – Liquid):
- Wood hardener will strengthen weak spots. It will also keep “punky” wood from continuing to rot (as long as it doesn’t get wet).
- Make sure you are close to completing the sculpting and sanding as wood hardener will make it difficult to sculpt or sand.
- Note: Fabric and wood are used in inconspicuous parts of the sculpture (on the back or behind) to strengthen or stabilize. These repair techniques may be noticeable and therefore not used where they can be seen. If the repair job can be done so that it is not noticed then, by all means, do it. If it can be seen, consider elimination or opening up the area as part of the design.
- When the wood, such as a limb, breaks completely off it can be pinned if glue alone doesn’t work.
- Choose a pin appropriate for the thickness of the wood being repaired.
- Thicker pins can be made of steel or brass rods, such as the ones used in basing. Thinner pins can be made from straight pins or needles. Tooth picks may also be used if strength is not an issue.
- Sharpen both ends and score the entire length of the pin. (Scoring will help adhere the pin to the wood when glued.)
- Use a tapered diamond bit to drill a hole (one that matches the width of what is to be used as the pin) in both pieces.
- Glue the pin into both pieces of wood.
- Clean off excess glue, let dry completely, and sand.
- Some filling may be needed to make the repaired joint not noticeable.
- Note: Review Wet vs. Dry Gluing above to determine whether to moisten the wood or not.
- For very large holes or voids Lamination may be needed if opening up the area doesn’t enhance the sculpture. To laminate, according to Webster is: To cover with one or more thing layers. In this case, to apply a very thin piece of wood over the hole or void and blend it in with the surrounding wood.
- If the void is large it may need to be partially filled before applying the laminate.
- Fill the void with very course sand paper or wood splinters mixed with glue to about 1/8” to the top. Let dry completely.
To make the laminate:
- It is essential to get the closest match for the wood laminate. If possible, use the same wood as the sculpture. Use a piece that was removed or had broken off.
- Cut a thin slice of wood that best matches the color of the wood and grain where the laminate will be placed.
- Make sure the laminate is thick enough to set into the void and have enough wood above to be sanded even with the surrounding wood.
- Make a template in the shape of the void:
- Place a piece of paper over the void and rub with a soft pencil or crayon to make an outline of the void.
- Cut, file, or sand the laminate piece to match the template.
- Depending on the size of the void, the angle of the surrounding wood (on a curve), or the size of the wood used in the laminate, more than one piece may be needed.
- Moisten the laminate and the filled void then glue in place.
- Fill the gaps between the laminate and the surrounding wood with glue and sawdust as described above.
- Let dry completely! If there is shrinkage fill again.
- Sand the entire area smooth. There should be no rough, jagged, or sharp edges.
- Don’t get discouraged — pretty much all problems can be resolved or “repaired”.