I am aware that the directions say Co2 is what take the gas bubbles out of Etex. But I think there is more to it.
Thickness of the topcoat.
Let me start by saying the initial heating of etex up to about 20 or 30 minutes will turn this stuff into practically water. I wont argue that you can breathe on etex and get rid of the bubbles. However I have found a better way. As you begin to heat the surface of the bait and the etex begins to run like crazy. the thinning of the epoxy and running actually allows the bubbles to get to the surface easier. Yes you have to continually rotate the bait because the etex is wanting to drip off however it gives you a much cleaner finish and virtually bubble free. Once heated and happy with the degassing...put on the drying wheel. The thinner etex allows the bubbles to escape faster and easier. A bubble would reach the surface faster in water than lets say syrup. A much thinner viscosity is created by heating. I have not tried heating devcon, but tend to think that this would expedite the set of the epoxy thickening the viscosity versus thinning. I dont use devcon other than for glueing bills in place. Perhaps some of the regular users of devcon could jump in here.
I think if I had the time and spare change I would get with Richoc again and get his prescription. I think he is on to something with superheating etex. An initial thinner viscosity allowing the bubbles to rise and escape and a super fast cure time... I believe he said 20 minutes or less. He also thins the etex with something prior to heating that allows him to shoot through an airbrush if needed. Again thinning should aid in relief of the bubbles.
Bubbles can escape easier with a lower viscosity topcoat. If the bubbles dont reach the surface or near the surface... all of the Co2 in the world wont help you.