by Mike - Alumilite » Wed Feb 08, 2012 9:05 pm
Another possibility for your buddies resin problem is moisture. Moisture in urethanes causes them to foam. If the bubbles are random throughout the part, it could have absorbed moisture and contaminated the resin in which there is not much he can do with it. Typical signs are lots of crusty stuff around the Iso side (B side) which will immediately react with relative humidity and crystalize. In the polyol side the moisture will absorb and you will not know it until you pour a part and the bubbles will form as the resin starts to cure. If there is a lot of moisture in the resin, the material will actually grow/foam.
This typically happens after opening and shutting the bottles many many times and when there is a lot of head space in the containers (most of the resin has been used). Another potential cause is if it is stored in a non temperature/humidity controlled area such as a garage or pole barn.
Just saying this could be a possibility from your description. If it is in the molds, the bubbles would be the exact same on every part.
Mike
Alumilite