Bubbles in Resin: How & Why They Rise to the Surface

[Hobart]

I've had several discussions relating to how bubbles of air trapped in resin during the mixing process are drawn to the surface by blowing onto the surface with a straw or by passing carbon dioxide from a propane burner over the surface. How do the bubbles of trapped air even know that the carbon dioxide is there and why are the drawn to the surface?

 

[Andy Resnick]

That sounds odd- why don't you think it's simply buoyancy?

 

[Hobart]

The resin I'm thinking of is very thick, unless you blow carbon dioxide onto the surface the resin will set with the bubbles inside.

 

[JaredJames]

I don't see how blowing CO₂ from a burner across the surface would bring out bubbles from within. Would be interesting to see a video if you have one?

 

[Hobart]

Hey well neither do I, that's why I'm at the collective brain otherwise known as Physics Forum. The technique is well known and comes with the instructions for the resin so it's no strange oddity.

 

[Danger]

I know that the technique is recommended in the user's manual for Envirotex Lite binary polymer. I don't know what chemical reactions are involved, but I do know that it specifies CO₂ as the catalyzing agent.