lumpy epoxy

wakerider285 · Criminal Joined: 04 May 2003 Posts: 50 City: Tequesta

I just epoxied my home made wakeskate and the epoxy wont smooth out, its all lumpy.
Does anyone know why this is happening and how to fix it?

adiocassette · Newbie Joined: 24 Jun 2003 Posts: 5

when i epoxied my wakeskate after about 3 coats, i sanded it with a light grain sand paper and then put two more coats on and that worked well for me

Dave W · Posted: Jul 10, 2003 12:17 pm Post subject:

If you end up with lumps, you can sand it down a little and then recoat it with either epoxy or varnish. Technically, you should always coat epoxy with a marine varnish as a final coat to protect it from UV rays. I didn't do it with my wakeskate because I just figured it wouldn't get left out in the sun too much. If you do attempt to recoat it with another layer of epoxy, be sure to sand it well even in the areas you aren't trying to work down. A waxy substance works forms on the surface of epoxy as it cures. If you don't remove it, another coat won't bond properly. I was told vinegar will cut the wax too, but if you're sanding it anyways you should be fine.

Not sure why your epoxy got lumpy. It might have started curing too quickly. It will cure too quickly for a few reasons: To much hardener, mixing too much at once, mixing in too hot an environment, or mixing it outside in bright sunlight. Both heat and sunlight will speed up the curing of epoxy. The kicker is that in a fast reaction (due to one of the above factors), epoxy actually produces a little heat as it cures. This produces a bit of a runaway effect. If the epoxy is curing too fast it will produce heat, which will cause it to cure faster, which will cause it to produce more heat, which will cause it to cure faster, which will cause it to produce more heat........etc.

I learned that one the hard way when I mixed up a large batch of marine epoxy and started using it in the sun. It got so hot that it started to melt and deform the plastic container I had mixed it in and it smoked a little bit. Also, be careful what you spread the epoxy on with. The bottom of my wakeskate has some funky streaks in it because I tried using a foam brush to spread it. The foam started to dissolve into the epoxy.