Creating bubbles in resin

[juno]

I know that some of you guys have done this . . . so I'm hoping there's a quick an easy answer.

I'm thinking about attempting this:

But I'm really unsure as to the process of incorporating such large bubbles into clear resin. The Orb of Thessulah seems a bit similar, so I was hoping for some advice. (There's another orb on Phil's ID the Buffy Props Thread that is similarly bubbled.)

 

[Great_Bizarro]

The cast resin"grapes" back in the 70's used to be a big hobby piece. I think they stirred the resin just prior to casting to get bubbles in the final piece.

 

[Jedi Lawja]

Back in '80 in Jr. High I had an industrial arts class on plastics. Everything from sheet plex to vacuuforming to fiberglass to.. resin. We had molds for 'grapes' available to us (small glass bulb that you filled with resin then broke when solid. They were quite large, an inch or more in diameter. To get bubbles we used to fill them with resin then agitate them. To be honest, we never made grapes, we'd insert a leather thong in the wet resin, put the other end in another bulb, let 'em harden, and you'd have a hell of a pair of 'klackers'. Sure, they shattered sometimes, but that was most of the fun.

Jay