Of all the steps involved in restoring old furniture, regluing is by far the most important. Poorly done refinish jobs can be redone; badly made replacement parts can be remade and reinserted; sloppy touch-ups can be removed and done over — all without permanent damage to the furniture. But shoddy regluing can, and often does, lead to the complete destruction of the furniture.
Despite the importance of the regluing step, only a small percentage of professional and amateur restorers do it well. As a result, much of our old furniture is becoming unusable.
There are five ways to reglue or tighten up furniture. In order, from worst to best, these methods are as follows.
- Use nails, screws, brackets and other metal fasteners.
- Insert white or yellow glue, cyanoacrylate (super glue), or epoxy into the joints without totally disassembling the furniture.
- Disassemble the furniture and apply fresh glue, usually white, yellow or epoxy, on top of the existing glue and clamp back together.
- Apply hot animal hide glue over the old hide glue that remains in the joints (after removing any loose or deteriorated glue) and clamp the joints back together.
- Clean all the old glue out of the joints, apply fresh glue (usually hide, white or yellow) and clamp the joints back together. In furniture with dowels, remove all the dowels that are loose and either reuse them after cleaning both them and the holes, or replace them with new dowels after cleaning the holes. Even better, replace all the dowels by drilling out those that are still tight but likely to come loose relatively soon. Then clean the holes and reglue the joints with new dowels as if everything were new.
Inserting nails or screws and attaching metal fasteners is the worst thing that can be done to furniture. Any stress put on the joints can cause the wood to split, and sometimes cause tenons or dowels to completely break off. At best, the fasteners just hold the joints together; they don?t make the joints tight.
“Wooden nails” (dowels) inserted perpendicularly through a wobbly mortise-and-tenon joint are just as destructive and difficult to deal with as metal nails. Unfortunately, many people find wooden nails somehow romantic, as if these nails are evidence of great craftsmanship, so they are sometimes added to old furniture.
Inserting Glue Into Joints
The practice of inserting glue into joints without disassembling the furniture is very widespread. Three methods are used: drip glue at the edges of the joints and hope it runs into them; drill holes into the joints and insert the glue through a syringe; and pull the joints open just enough to expose small parts of the tenons or dowels and apply glue to them.
The glues most often used with this technique are cyanoacrylate and epoxy, though white and yellow glues are also used. Cyanoacrylate and epoxy are more expensive and difficult to use, but it’s usually reasoned that they are stronger.
Though this method produces joints that usually remain tight for a year or so, long-term soundness rarely occurs because only a part of the surface area is reglued, and it is still sealed with old glue, so the new glue doesn’t get to the wood.