: I might be wrong, but I thought it was in Nick Schade's book "The
: Strip-Built Sea Kayak".

The bubble roller is mentioned in Nick's book, and I agree with Rob that you don't need it unless you are compressing multiple glass layers. On my current boat I followed Rob's shop tips, "How To Make a Transparent Glass Layup". Rob's method worked great for me, and I didn't battle with any excessive bubble problems. Be sure to use the high quality yellow foam rollers to apply resin, as less dense, black foam rollers can induce air bubbles. The air bubbles can be eliminated using a squeegee as Rob points out.

Read the shop tips at Laughing Loon -- here's a link.