1. Twist out damaged screws with an extractor
Major furniture repair often involves disassembling the piece and putting it back together. Sounds simple enough: knock things apart and glue them back together. But anyone who’s tried this knows that it never goes that smoothly. This article will show you some slick ways to deal with the most common and frustrating aspects of the job. Plus, we’ll show you some shortcuts that might help you avoid disassembly altogether. Just keep in mind that these methods aren’t meant for fine antiques. If you suspect that a piece of furniture is especially old or valuable, have an expert take a look (see “Antiques-Repair & Restore” in the Yellow Pages).
2. Drill holes to get a grip on nails
Some nails are easy to deal with. Sometimes you can separate the parts and then remove the nails. Other times you might be able to drive a nail right through the part and out the other side. If you can’t get hold of the nail’s head, drill holes just large enough for needle-nose pliers—on opposite sides of the nail shank. Run the bit right along the shank and bore as deep as the shank. This will help to loosen the nail.
3. Hollow out, then chip out broken tenons
When half of a dowel or tenon stays in its hole, you’ll be tempted to grab a bit of the same size and completely drill it out. But this is almost certain to leave you with an enlarged, off-center hole. Instead, use a bit that’s about 1/8- in. smaller than the socket. Then break out a section of the remaining material and the rest will chip out easily. A small carver’s gouge is the perfect tool for the job, but a narrow chisel or even a sharpened screwdriver will work, too.
4. Disassemble with a hammer
Despite the variety of spreading clamps and prying tools available, hammers are still the favorite disassembly tools of furniture repair pros. Some use rubber mallets, others like dead-blow hammers, which have heads filled with sand or metal shot to eliminate bounce-back. Either way, you’ll need a collection of wooden blocks, cardboard or carpet scraps to prevent surface damage. Cover your workbench with carpet or a heavy blanket and swing away. Try to knock joints straight apart. Some twisting and wrenching is inevitable, but keep it to a minimum and you’ll avoid breaking joinery.
5. Inject epoxy into loose joints
This is a fix that makes furniture-repair purists cringe, but let’s face it: some pieces just aren’t worth the time it takes to make a first-class repair. Epoxy injection is fast and easy, but also a bit of a gamble. It doesn’t work every time and if it doesn’t, you’re stuck with a loose joint that’s almost impossible to pull apart and re-glue.
The goal is to force epoxy into the pocket between the end of the tenon and the bottom of the mortise or socket. That way, epoxy will flow into gaps around the tenon. The hole you drill into the pocket should be sized so that the tip of your syringe seals tightly when inserted. As you apply pressure to the syringe, wiggle the loose part so epoxy flows all around the tenon. You’ll get the best results using low-viscosity epoxy that will inject and flow easily.
6. Heat and scrape off glue tenons
New glue doesn’t adhere very well to old glue, so you have to get rid of the old stuff before reassembly. Turn a heat gun on old glue, and it reacts just like old paint, becoming soft, gummy and easy to scrape off. Just remember that a heat gun is designed to destroy finishes and can even ignite wood. Have a wet rag handy to keep things cool.
7. Shavings and hot water get glue out of joints
Scraping, sanding or reaming old glue out of a socket or mortise is slow, tedious work. And it’s tough to do without enlarging the hole. So why not let heat and moisture do the work for you? A big syringe lets you put steaming-hot water right where you want it and crushed shavings from a block plane are great for soaking up the softened glue. You might have to repeat the process a couple times, but it’s still safer than other methods.
8. Rebuild a broken tenon
A broken tenon may seem like a disaster, but it’s actually pretty easy to fix. The first step is to trim off the rough, broken end. Then glue in a block in place of the missing tenon. If you’re fixing a chair leg or some other part that will bear a lot of stress, use epoxy, because standard glues don’t bond end grain very well. With the block in place, drill a dowel hole through the block and into the part. The photos at right show the rest of the process.
9. Wrap up a worn down tenon
When a joint loosens and begins to wobble, the tenon and socket wear each other down. To enlarge the tenon and restore a tight fit, wrap it with a shaving from your plane. Keep in mind that wear and shrinkage turn round sockets and tenons into ovals.
10. Insert a spindle or rung
A broken spindle or chair rung can be removed well enough. But how do you get the repaired or new part back in without major disassembly? The answer is a scarf joint: a long, tapered cut that provides plenty of surface area for a strong glue joint. A scarf joint is less visible than a simple crosscut.
11. Restore strength with steel
Most furniture fractures can simply be glued back together. But some breaks are messy, leaving splintery fractures that won’t form a strong glue joint. You could replace the entire part, or you might be able to reinforce it from inside—usually without removing it. Begin by gluing the part back together as you normally would. Next, you’ll need a long drill bit and a steel rod cut to length. Diameters depend on the repair, but the bit should be 1/16 in. to 1/8 in. larger than the rod. Steel rod (threaded or smooth) and 12-in.-long bits are available at home centers.
12. Through-dowels for loose joints
Any joint that can be drilled into from one end is a candidate for a through-dowel. This is an easy repair, but leaves holes to plug, so it isn’t for cherished heirlooms. You can make your own plugs with a plug cutter ($4 at home centers) or buy them. Face-grain plugs blend with the surrounding wood better than plugs cut from end grain.
13. Choosing glue for repairs
Strong and convenient, yellow wood glue is a good choice for most repairs. But there are glues that offer advantages for special situations:
SLOWER GLUES Depending on factors like temperature and wood species, standard wood glue can set in as little as five minutes. When you need more time for complex assemblies such as chairs, try liquid hide glue or Titebond’s Extend, a slower-setting version of yellow glue. Both offer about twice the open time of regular wood glue.
FASTER GLUE Cyanoacrylate, often referred to by the brand name “Super Glue,” is perfect for small repairs because it sets in minutes or even seconds depending on the formulation. Instead of finding ways to clamp small or odd-shaped parts, you can hold a repair together by hand until the glue sets.
GAP-FILLING GLUE Although mixing is a pain, two-part epoxy is the best choice for a joint that doesn’t fit quite right. Epoxy makes sloppy-fitting joints strong because it becomes a firm, strong-bonding gap filler as it cures. Standard wood glues shrink as they dry and are too brittle to bridge gaps. Polyurethane glue expands to fill gaps, but doesn’t cure hard enough to become a sturdy gap filler.
14. Rehearse before you glue
Clamps are great for squeezing flat, parallel parts together, but most furniture throws you a few curves. Even a clamping job that looks simple can turn out to be tough. So don’t touch that glue bottle until you’ve done a complete dry run. Here are a few tips for dealing with some tricky situations: