> Andy Draper described it to me as a matter of chemistry (Andy -
> apologies if I've described this incorrectly). Apparently the curing is
> a reaction involving hydrogen from the hardener. Water provides an
> alternative hydrogen source, and hence affects the cure.
>
> Regards,
> Jeremy
Seems indeed so. The general objection in various epoxy data sheets
is a chemical one, where high humidity forms acids which affect cure
time, strength, adhesion, and/or causes amine blush and surface
tackiness. Liquid H2O can penetrate many cured resins by osmosis if
given the time, a factor affecting boats and epoxy floor coatings
where especially freezing cycles causes blisters. If mere humidity
can cause that, I can't find a reference. Epoxy is generic for a wide
variety of stuff, and includes water based formulations. So whatever
mfr says is humidity limit for their product, it's advisable to follow
I guess!
Best,
Fred F.
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