I use Polyester resins from a manufacturer here in Ontario, Ca. They ship all over and are very reasonable. My e-mail is [email protected]
Send me an e-mail and I will get you the info.
It sounds like your mixture is off like was said before. Resin is very temperamental, you have to be pretty close. Also, you may have the wrong hardener which will produce the results you are getting. You want resin with a 3-4 minute pour time. You actually get about 2 min. as the material gets too thick to pour into molds. If moisture contaminates the resin, you get get what looks like crystals floating in the container and suspended in the fluid. Just run this through a pany hose strainer and the material is still ok.
When the resin has passed its useful life, you will know because it will grow outside the molds and have alot of tiny air bubbles trapped in the castings.