|Home » Forums Ľ Professional Finishing Ľ Message||Login|
You are not logged in. Consider these WOODWEB Member advantages:
Fuming and wood glue1/13
I've never fumed wood, but I thought it was a surface reaction with the tannin that changed the color. But you are saying it actually gets inside the wood at a cellular level?
I havenít done it before either, Richc. Thatís the problem. Iím not sure how deep it will go.
It's possible that ammonia may have no effect on the glue. Conduct a test with some glued up pieces and apply straight ammonia once the glue is cured to see if it weakens the joint. I'm guessing not, since fuming has been done for ages.
Ammonia *should* dissolve PVA and similar glue that isn't cured. It will not dissolve the cured form and usually won't even weaken it. So it would dissolve uncured titebond ii or iii.
Titebond original, however, is an "aliphatic resin", which tells you nothing†meaningful about the chemistry (IE there are an innumerable amount of things one can call an aliphatic resin)
Without knowing more about the chemistry of the glue, can't tell you if it would be dissolved in cured or uncured form.
As for whether fuming ends up a surface treatment or deeper in the wood, that depends mainly on porosity of the wood and pressure or vacuum being applied.
But for the purposes of dissolving glue, in practice, if it's going to dissolve exposed glue, you should expect it to be able to dissolve the entire joint given enough time.
Wood joints are rarely air tight enough to be able to prevent gas from getting in
(I'm too lazy to calculate whether there are other reasons, like relative pressures, etc, that the ammonia gas may not displace the air in parts of the joint)
I don't think the fuming really penetrates that deep into the wood. Ive heard of entire bank lobbies being fumed years ago and they probably used hide glue.
Thanks to everyone who answered.