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Undoing Glue Joints
Issue: Issue 238
Posted Date: 12/15/2009
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I need to disassemble a coffee table I made. Is there a “trick” to undoing glued joints? - John
Chris Marshall: The first “trick” to disassembling a glued joint is remembering what kind of glue you used to put it together. If it was hide glue, hot water will dissolve it. If you used white or yellow glue, hot water, acetone, toluene or xylene will dissolve them. Nothing I know of works on epoxy or poly glue. The second trick is getting the dried glue wet with the right solvents — and that’s tough to do on a closed, tight joint. If there’s any gap, use a small syringe to squirt the solvent where you need it, and give it plenty of time to break down the glue. Good luck — it won’t be much fun!
Rob Johnstone: With the exception of those made with hide glue, glue joints are simply not made to come apart after the glue has cured. With that said, you can break down white and yellow glues with a combination of heat and moisture. When luthiers reset guitar necks, they commonly inject steam into the joint to release the glue. It is a messy and tedious process.
Epoxy will break down under heat. Most epoxies will release after they get to 250-degrees Fahrenheit. Hide glue will release with a combination of water and pressure. It is the most civilized of glues in this regard. Violin family instruments are assembled with hide glue because they need to be worked on - disassembled and the put back together on a regular basis. There are Stradivarius violins that are 300 years old that are still around and being played in orchestras. So hide glue is a viable product even today.