Glue for Borax Treated Board

Wood that has been treated with borate-based chemicals interacts with water-based glue in a way that interferes with the bond. July 28, 2012

Question
I have some old Medite-FR (fire retardant) that has been treated with Borax. Apparently the borax sucks the moisture out of the glue before the PVA glue has a chance to set. SierraPine has since changed their formulation for the FR, but I'm still stuck with the old stuff. Does anyone have any recommendations for glue?

Forum Responses
(Adhesive Forum)
From contributor P:
We've run into this a lot lately and the key is to do a little surface prep. There's really no adhesive available that won't react with the Borax but if you wipe the surface with a moist towel and use a little heavier spread the panel usually comes out just fine.



From the original questioner:
We did a pretty thorough prep on the board as it was totally covered with Borax (and probably other unknown mineral salts) and the laminate (simple white liner) just lifted right off. Not even close to sticking. Most of the glue stuck to the liner but hardly any to the board. If we use contact cement, that will telegraph through the thin liner.


From contributor C:
If you are hot pressing, try a urea resin glue. Thatís what we do, and you need to run at 90-100 C. It's not a water-based glue like PVA.


From contributor P:
Urea Resin is a water-based adhesive. Borax does not react with it the way it reacts with PVA but it does react. It changes the pH level of the glue and causes it to cure much more slowly. This can be overcome in a hot press but the operator should be aware of the possible need for increased press times.