Getting bubbles in 2 part urethane 1

[TheJman]

Hello, I'm using a 2 part acrylic urethane and applying it with a brush to a sanded epoxy surface. I am letting it sit for 15 minutes after mixing (says to for induction time), but no matter what I do I get random air bubbles after brushing it on. Sometimes they don't appear for 5-10 minutes, or even longer. I don't think it could be outgassing from epoxy though.... Does using an airbush or roller help?? Baking/heating? Any ideas to eliminate the bubbles are greatly appreciated.
Thanks.
-Justin

 

[Compositepro]

Vacuum degassing is the most effective method of buuble removal. Brushing, however can reintroduce bubbles. If you only see bubbles 15 minutes after brushing your problem maybe the urethane reacting with moisture to create CO2. You may have a moisture/humidity problem.

 

[TheJman]

Great, thanks. I started building a vacuum chamber already, but do you have any recommendations for the materials (walls and glass/plexiglass)?
Thanks.
-Justin

 

[aaca]

you can use some ideas from:

http://www.hippwrap.com/about.htm