- Joined
- May 25, 2006
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- 2,440
Epoxy chemistry uses a hardener which must me mixed in the proper ratio to react with the resin molecules. The hardener is consumed by attaching to reaction sites on the resin molecules. Polyester chemistry uses a catalyst that is not consumed, once a resin molecule bonds to another resin molecule, the catalyst moves on to another reaction site. Epoxy hardeners are affected by moisture and sometimes oxygen. Too much hardener is just a bad as too little. I always mix epoxy resins by weight.