Hello Bill I had this problem at one time and found that the carbon fiber had a light mesh of material to hold it in shape. The problem is that this material has a reaction to the epoxy and generates a gas (out gasses) which makes the bubbles. Two things will cure it. One is to remove the mesh material or use carbon that does not have it. The second thing is to use an oven to cure the epoxy at an elevated temperature. Not over 110 deg F. I wrote an article about using hot boxes. It was in the RCSD. The first issue that was the new large format November a couple years ago. There also was an article in the AMA soaring column just recently. It covered the same thing and gives a reference to my article. One more thing when a bubble starts take a pin and put a hole in it and it will not grow any larger. Good luck. Del RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]