I was quite worried about warping. You can see in the pic that I used a thin plastic to cover everything.I did the carbon with fast set Raka hardener, and as soon as it was hard (green) I took it off, cut the carbon to size (which was easy if you flip it onto its back and use a sharp knife,using the wood edge as a guide) as soon as I cut it, I immediately put it in place and glassed it. Thankfully it didn't bow, or I would have had to use T pins or something to hold it.