I need to deteriorate a door joint for disassembly, reduction in size and reassembly. Can you offer any suggestions on the best solvent to use to do this? – Bob Burns
Rob Johnstone: Unless you used hide glue on the joints, there is no solvent that will break down the glue in a joint. You can use steam pumped right into the joint to loosen the glue. (It’s no small job.) We do this when we are removing guitar necks from the body when they have to be re-set. But glue-up remains the major woodworking operation that is not reversible. I am sorry to have such bad news. And believe me, I know your frustration because I have been in your situation.
Tim Inman: I’m with Rob. These joints are really tough to destroy – especially if you’re not wanting to do much damage in the process. As a restorer and conservator, I often have used pressurized steam injected through a veterinary sized needle right into the interior of the joints I needed to open. This requires the equipment, of course. It also requires a little good old-fashioned “Superman” X-ray vision or intuition. You have to imagine in your mind’s eye where the joint is internally and when you’ve drilled into it, in order to get the steam needle where you want it. Even then, it takes time and – often – force. Another option is a Japanese razor saw. These are very thin blades that cut on the pull stroke. You can often saw right down through the joint and cut off the tenons or dowels without doing much harm to the sides of the wood. Then, you’ll have to reinstall either a floating tenon or new dowels.