No matter how careful you are when working with veneer, you’ll need to make the occasional repair. Veneers get chipped, scratched, dented, or blistered, and to be good at veneering, you also must be good at veneer repair. Not to worry. Just ask yourself the philosophical question: If you execute an invisible repair, did the damage ever really occur?
While my focus is on the construction process, the methods described here also can be applied to restoration, and some even work on solid wood. Keep in mind that existing glue and finish (topics I won’t address here) are big factors in restoration work. Also, when building a piece, it’s important to catch repairs early in the process; otherwise, construction could get in the way, such as with solid-wood edging or a frame around a panel.
Having an arsenal of remedies will get you through even the toughest of repairs, and experience will help you match the appropriate repair to the damage. I work with thin commercial veneers, but the same techniques apply to thicker, shopmade veneer.
The first thing to do with damaged veneer is judge whether a repair is necessary. Don’t jump into a full-blown repair if you don’t have to. A small chip or dent on the edge of a piece often disappears when you break the edges, or you can be a little heavy-handed on that spot to ensure that it does. And there is nothing wrong with using putty once in a while to fill a tiny chip, crack, or split. It requires skill to color the putty with water-soluble aniline dye powders to match the wood perfectly. This fix should be used rarely and when the damage is very small, but it can save you from cutting into the veneer when it isn’t necessary.
Sometimes, to make a good repair you must first make the damage worse. A chip, loose edge, or split can be too small to repair successfully. If you try, you’ll most likely fail, causing a bigger mess. The only option is to “cut back,” or extend the damage into the surrounding veneer. This creates the ideal situation for a successful repair because it provides enough space on the substrate to get good adhesion and allows you to control the shape of the patch.
If you’re not careful spreading glue and applying clamping pressure, an air pocket may form.
Slice the blister to insert glue. Follow a grain line, streak, or other figure to camouflage the cut. Lipp uses a small spatula made of aluminum flashing to work glue into the pocket one side at a time.
Clamp the repair. Use a nonstick caul (a block wrapped in wax paper or packing tape or a piece of phenolic plywood) so you don’t glue the caul to the veneer.
Clean up the repair. When you pull off the block, it won’t be pretty. Carefully scrape and sand off the squeeze-out to bring back bare wood. Darker woods hide this repair best.
When choosing glue for a repair, try to match the veneer color as closely as you can. This way, if glue bleeds through the pores it will be less visible. For example, use white glue on maple, a tight-grained wood that is not usually stained. However, rosewood is a dark wood with open pores; white glue would bleed through and ruin it during finishing. Choose something dark instead, like urea formaldehyde glue. Also, any water-based glue can be colored with water-soluble aniline dye powders to match the wood.
Your goal should always be to minimize the visibility of the repair. You don’t want to accentuate it with gluelines or glue in the pores. Keep everything as clean as possible, since even the dirt from your fingers can work into white glue and leave a dirty black line.
Dents can be difficult to disguise. Before starting any repairs, steam out the dent as much as possible.
Cut a patch to match. As with all repairs, success depends on how well you match the new veneer to the old. A rubber pad between the repair and the caul forces the patch into the dent.
Clean up excess. Carefully pare away the edges of the new veneer, then feather it in with a hard block and sandpaper.
Hide the repair. When every-thing is smooth, you should see only a slight outline where the dent was. You can use wood crayon or dyes to draw grain lines to disguise the patch.
Slice blisters to work in glue
Blisters are small pockets where the veneer wasn’t glued properly to the substrate. A veneer blister is contained; it doesn’t have an opening that you can see or reach. The best way to check the size of a blister is to tap all around it with your fingernail. You’ve located it when you hear a high popping sound. I pencil around the perimeter of the blister so I know where to work.
Once you’ve located the edges of the blister, the next step is to cut thin slits in it. The number of slits you need will depend on the size of the blister (as a benchmark, I usually cut one slit down the center of a 1-in.-wide blister). Make the slit the same length as the blister to provide complete access for glue.
I use an Exacto knife, a small art spatula, and a bottle of glue that has a tiny open-ing. Once you are finished gluing, get good pressure on the blister as fast as you can. Whether you use clamps or weights, remember to use a hard caul so the blister glues down smooth and flat.
Dented veneer can be tough to repair. Because commercial veneer is thin, scraping and sanding aren’t viable options. Filling it with putty is, but the color usually doesn’t match, and unless you are very good at touch-ups it will stick out. Fill the dent with glue and spread some about 1⁄16 in. beyond the perimeter of the dent. Lay a new piece of veneer over the glue-filled dent, put a rubber pad and a caul over that, and apply pressure with a clamp. You want a fair amount of pressure to force the veneer into the dent, but not so much that you make a larger dent. Once everything is dry, it’s easy to clean up the squeeze-out with a chisel and sandpaper.
Splinters are chipouts that occur at the end grain of veneer. If you are lucky, the splinters will be connected but just folded up. In that case, just apply some glue to the bottoms of the splinters and clamp them back in place.
But if the splinters are lost and you can’t find them after scouring your shop floor, take a matching piece of veneer and break it across its long grain to replicate the missing splinters. This may take a few breaks. To glue a splinter into place, slide it into the void so that it not only glues down to the substrate but also edge-glues to the veneer. When sliding the splinter into the void, use a bit of pressure so that it really smashes into the surrounding veneer, almost to the point of sliding under it. This will eliminate the glueline. Clamp with a nonstick caul to put pressure on the repair.
3. End-grain edge damage
Splinters often happen when trimming back overhanging veneer that is glued to the substrate or when an edge gets caught and ripped up. Small splinters can be replicated; for larger damage, tombstone repairs are best.
Splinters – Mimic the damage. Lipp breaks several matching splinters that he’ll glue into place, using a hard caul and a clamp to apply pressure.
Trim the overhang. Wait for the glue to dry and be careful, or you’ll have to repair the repair. With a chisel, use a downward shearing motion.
Clean up the patch. Light scraping and sanding should leave an imperceptible patch. Here, Lipp uses a shopmade scraper.
Round patch – Set up a plywood fence. Align and clamp a fence so that it will guide a router bit directly over the damage. With the depth set to the veneer’s thickness, run the router far enough along the fence to clear away the problem area.
Make the patch. Lipp cuts a strip to fit the width of the void, and then uses a gouge to round the top.
“Tombstone” shape is best. This repair is better than the bird-mouth or “V” repair, because angular seams tend to show. If matched well, the curved top of this repair will disappear.
Another great repair trick I use is the “tombstone fix.” I like this technique because it is quick, controlled, and very effective when the damage is relatively small, on the top of a workpiece, and close to the end. A light-duty router and a straight bit are two great tools to use when repairing veneer this way. The bearing on the router bit gives you complete control over what you remove, and the depth of the cut is easy to set to the veneer thickness.
Set up a 3⁄4-in.-thick plywood fence running in the direction of the grain; most of it should sit on the workpiece, with just 1 in. hanging off the end. Clamp it in place, so that a 1⁄2 -in. straight router bit, with a top guide bearing, will run over the damage as the router base runs along the fence. Set the bit depth to the veneer’s thickness and cut away the damaged area. Next, find a piece of veneer that matches the grain and color and cut it to 1⁄2 in. wide. Check to make sure it fits well; slightly too wide is good because you can smash it in when gluing. Cut the end of the veneer piece into a half-round to match the cutout. If you have a sharp 1⁄2-in. gouge (carving or turning), this will be easy. Test the fit of the piece. To glue, push the piece down and in to the cutout so that the seam disappears.
What if damage occurs along one of the long-grain edges: for example, a chip or a cross-grain scratch? The dilemma is how to begin and finish the repair. Angular lines will show, especially on a repair like this where they would run across the grain.
In this situation, the best repair looks something like a section of a circle—tapering in from the edge, hitting its apex right at the damage (make sure you just clear it), and then tapering back to the edge. The patch size will depend on the position and size of the damage. You should also try to match it with the grain.
The first step is to cut out the shape you want from a piece of 3⁄4-in. plywood and sand it smooth. Clamp the plywood template in place and cut out the damage. Now cut a piece of mating veneer to match and fill that void. Glue the piece in, and clamp it down with a hard block. This will give you a seamless repair.
4. Long-grain edge tears
Clamp on a template to cut away veneer damage and create an identical patch.
Score along the edge of the template. Use the flat side of a single-bevel knife to score and cut the section. Then use a chisel to pry the damaged veneer away from the substrate.
Create the patch and glue it in place. Use the same template to match and cut the mating veneer. Mark the template and the patch for length and grain match, and then line them up and cut. Set the patch in place and tape one edge. This will allow you to swing the patch up (maintaining its position) and apply glue before clamping it down with a hard caul.
An invisible curve and taper. The tapering ends of this curved repair completely blend into the original veneer.
5. Major patches
A large area of damage, or damage located toward the center of a workpiece, requires an extensive patch.
Set up the templates. Arrange the templates with the center piece covering the damage. Once the two outer pieces are firmly butted up to the center piece and clamped, tap out the center piece. With a bearing-guided router bit set to the thickness of the veneer, rout out the entire area.
Cut a new strip. Clamp the center template to a matching strip of veneer and use it as a guide, cutting around it with a knife. Align and glue the patch. Use tape as a hinge and apply glue only in the recess to prevent the veneer from expanding too soon and curling. Taping along neighboring edges (before clamping) makes cleanup easier.
A big patch doesn’t mean a more noticeable repair. Once dry, just a little scraping and sanding removes excess glue, revealing a barely visible restoration.
When damage is extensive and is not close to an end or an edge, you may have to replace a strip of veneer that spans the length of the piece. Again, you’ll need a router and a straight bit. My method allows you to match the cutout section precisely.
First cut a piece of plywood to a width that covers the damage and a length that overhangs the workpiece by an inch on each side. This piece represents the strip that you will rout out and the patch. Once you have it exactly where you want it, clamp it in place from each end.
Cut two more pieces of plywood, about 4 in. wide and as long as the first piece. Clamp one to each side of the center strip, keeping the clamps back far enough so that they don’t interfere with the router. With a hammer, tap in these outer pieces so they tightly butt up next to the middle strip, and then tighten the clamps. Next, unclamp the inner strip and gently tap it out. That leaves you with a gap that will allow you to cut a perfectly straight and parallel strip out of the veneer. When you are finished routing, remove the clamps and plywood from the panel.
Selecting a new strip of veneer to glue into place is easy if you have the next sequential piece in the flitch. If not, choose something as close to the original as you can. Lay the center template over the veneer and clamp it. Cut the veneer by going around the plywood with a single-bevel knife, banking the flat side of the knife against the plywood. This creates a mating piece to glue into the routed area. Lay the piece into place, sliding it where it looks best and taping down one side. Once glue is applied, quickly flip the veneer down. Make sure the loose edge is in place and tape it down. Clamp a 2-in.-wide, nonstick hard caul over this repair, making sure that the caul covers the two seams.