Bubbles in 105/207 West Systems Epoxy ?


We just put on the first coat of epoxy on the new hatches, as an undercoat before we put on the Epiphane.

We used the roll-and-tip method, rolling it on with an epoxy-proof roller and tipping it with foam rubber brushes. The hardener was old, a year in the garage and we had to poke a hole in the dispensing tube before we could pump it out. I worried that the catalyst might not be pumping out a full measure for each stroke but after a few hours the coating really started curing and I think we have a really good seal.

My question has to do with the bubbles that popped up after the curing started. I've attached a picture to better describe it.

We had the dust filter running for hours as we were working on the hatch frames but obviously something was floating around to land and cause bubbles. What would make epoxy do that ? It isn't a problem as well sand down the surface and re-epoxy it a few times before hitting it with a few coats of Epiphane.

Just curious,



  • Epoxy bubbles.jpg
    Epoxy bubbles.jpg
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Innocent Bystander
In my experience bubbles like that happen occasionally but especially when I've applied epoxy to wood that warms up due to increasing ambient temperature as the epoxy cools. Warming conditions make air embedded in the wood expand, creating bubbles. I think the West manual suggests applying epoxy after the hottest part of the day.

Chances are that once cured any trace of those bubbles will be easily sanded out.


Sustaining Member
Blogs Author
Air in the wood

Yes, its air in the wood that is displaced as the epoxy seeps down. It can either be sanded down, or if you want a smoother finish put another coat of epoxy on before you varnish. I built a wood kayak and the first coat always bubbled like that. Subsequent coats should not.