Do you have an odd-shaped or -sized resin casting product? This method is for you! It's cheap and doesn't require a vacuum pump.
NOTE: this does not produce perfectly perfect resin casts. All of my jewels turned out a tad lumpy. This won't be an issue if you're painting over your final resin product, though-- just sand the lumps away.
I also fail at the actual resin casting, and there are a zillion other tutorials out there for that. However, if you're using Castin'Craft resin, ignore all the 1:10 catalyst:resin ratios. Using too much catalyst nullifies dye and turns everything yellow. >_*
All credit for the original idea goes to , who then collaborated with me for the final product.
I'm just happy we both ended up with a final piece. I'm going to try a few more things with the molding and resin. Like the electric toothbrush idea and a few others. I'll keep you up to date on what happens.