Tools and Wood with Bob Smalser

   

Are Your Glue Joints Repairable?

 

1 of 5

 

Have you done a simple builder’s test of your favorite wood glue to see if it can be re-glued successfully should either your work be damaged, or a cross-grain glue joint fail with age and seasonal movement?

On identical tiles of freshly planed, vertical grain, second-growth Doug Fir, I saturated the faying surfaces with glue and let them cure to full strength by the manufacturer’s instructions for time and temperature.

Then I keyed each faying surface with 100-grit abrasive paper, re-glued them with marine epoxy, and “clamped” the assemblies to the degree favored by epoxy.  For glues that left a rough surface like polyurethane, the epoxy was applied twice… an unthickened coat followed by a second coat thickened with West 404 High-Adhesive Thickener, per the manufacturer’s instructions.  I let the epoxy cure for 6 days to reach full strength.

I purposely chose small blocks of wood with easily broken short grain because strength here isn’t the issue, adherence is, and I can check adherence using a sharp chisel without trying to break long glue joints in a press.  Of greater concern was that the glues to be tested were applied without any clamping pressure, but as it turned out, several glues that require high clamping pressure fared very well, so I believe the results are reasonably valid.

The initial results offered no surprises.

1 of 5

   
 
 

For best viewing experience use Microsoft Internet Explorer.
Copyright © 1995-2008 wkFineTools.com and Wiktor Kuc.  All Rights Reserved.
Designated trademarks and brands are the property of their respective owners.