Craft question: clear liquid that hardens?

[supergoose]

I have seen items that mimic the look of water using clear hardened substances (like a fake water-filled goldfish bowl, or something). I gather that it is a kind of epoxy/resin that goes from liquid to solid via the edition of a catalyst. I'm looking for one that hardens into a completely colorless, transparent, hard substance and that can be used in glass and polymer clay containers with 'floating' polymer objects (bonus points if you can put any kind of plastic in it).

I need it to not have loads of bubbles or be opaque when it sets, and to be able to use it in very small amounts. I'd also like to be able to color it without losing the transparency, and for convenience, it'd be good if I could add opaque color too.

So, any suggestions? A look on dickblick.com turns up Castin'Craft Clear Polyester Casting Resin (http://www.dickblick.com/zz335/20/). Will that work for my purposes, do you think?

Thanks a lot.