Replies

1. 
   Alan | Apr 11, 2003 03:54am | #1

   Butch,

   If you find that magical solvent that dissolves old glue, then quickly evaporates, taking the glue with it, and doesn't affect the wood, please let me know.  We can make a million!

   Seriously...  Some glues can be softened--a little--by various means, but nothing I know of will do what you're describing.  To properly repair the joints on your chair you have to remove all the old glue, both on the tenons and in the mortises.  That, unfortunately, means you have to scrape and sand and file and do whatever else to get all the old glue off.  I know of no other way.

   For your repair to last the joints have to be tight.  The mortise and tenon should be a snug fit:  meaning you should be able to put them together with just hand pressure, and maybe a couple raps with a mallet.  If you have to grunt and strain, or use lots of clamp pressure or lots of heavy blows with a dead-blow hammer, they're too tight (unlikely).  If they don't stay together on their own, they're too loose (most likely).

   If they're too loose you have a few options, the easiest being to use a gap-filling glue that itself has structural strength.  Epoxy is probably your best choice.  But epoxy isn't the best answer.  Other options; try swelling the end of the tenon by with water (not recommended--it will probably just shrink again).  You can also cut off the end of the tenon, drill a mortise into the tenon for a dowel that's a bit larger than was the tenon, and then fitting the new tenon into the old mortise.  You can also plug the mortise with a dowel, and then re-drill a mortise for a snug fit with the tenon.

   I believe there are products available that say they will swell the wood in loose fitting joints and make a permanent repair.  I've never used these, and I'm suspicious about the quality and longevity of such a repair.

   Others may have some ideas for you too--and maybe there is a miracle product I don't know about (that wouldn't be too surprising).

   Alan

2. 
   forestgirl | Apr 11, 2003 05:16am | #2

   Is there any chance the residue you're seeing is from hide glue?  I don't know what it looks like when it's old and dry, but if it happens to be hide glue, it can be softened with distilled water. 

   There is a product called "De-Glue Goo" that's for removing water-based adhesives.  You can get it at VanDykes:

   http://www.vandykes.com/product/02348098/

   Here is an excerpt from the Martin O'Brien Cabinet Maker web-site:

   "An example of a conservation guided repair on a loose chair would be the use of traditional animal hide glue instead of modern “woodworker’s” glues. There is virtually no difference in the holding strength of these two glues. Hide glue always remains soluble in water and in itself and old hide glue in a chair joint does not have to be removed for the new hide glue to adhere. Modern glues do not share this unique property, in fact, some modern glues require rather invasive wood removal in order to remove the glue. Modern glues aren’t meant to harm things in this manner, but they do in an inadvertant way. Chairs in particular are prone to coming unjoined with use. So it makes sense to use a glue that will cause inadvertant damage."

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)

1. 
   SenorDorado | Apr 11, 2003 01:42pm | #3

   Thanks for the tips!

   On the subject of the old pink glue, there's only one way that I know of to see if the distilled water works and that is the old experimentation method that was developed aways back.

   Have you actually used and had success with the "Moo-Goo" from VanDykes?

                                                           Work safely!

                                                               Butch

1. 
   forestgirl | Apr 11, 2003 06:36pm | #4

   Nope, can't say that I have (tried the De-Glue Goo {MooGoo -- too funny}), but I bet if you post a thread "De-Glue Goo MooGoo???" Knotheads will certainly take a look and answer if they've used it.  Seems like someone here mentioned it once.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)