"clouded" epoxy

[sneuman]

I used some West System on the exterior of my boat yesterday. No rain in the forecast, so thought I was safe. However, this morning it was foggy/dewy and while the epoxy was dry, it had several minor milky white streaks in it. Has this damaged the integrity of the epoxy? Should I apply another coat (it's not glue formulation, but the "special coating" one)?

[imagine2frolic]

Do you mean 207 hardener?

[sneuman]

yes. 207

[David M]

I hate to say this, but 207 cannot tolerate a high degree of moisture while curing. I used the same thing as you for the britework in the boats salon. There was one day when the same thing happened. I waited and waited for the cloudiness to go away but it never did. I ended up sanding off the worst of it. I now keep a heater going overnight so the air does not get close to the dewpoint when I do britework so this does not happen again. Also, make sure the moisture content of your wood is low as well. Yes I know, you are not supposed to run electric space heaters in boats when you are not there....I take my chances overnight so the stuff cures properly.

[sneuman]

ah, problem is it was exterior. and yes, i am planning several coats of varnish over for UV protection. Not concerned about appearance so much, as the varnish will take care of that -- more worried that it is OK otherwise.

[Wotname]

FWIW, an epoxy chemist has advised me that the "cloudiness" due to moisture while curing has no significant effect of the structual porperties of general marine epoxies.