I've only had this twice. First time I ignored it as a random oddity. But its happened again. Ive had "print through" (if you want to call it that) from the backing layer through to the surface. Its not print through as in the carbon fibres showing through the resin, but the patching of backing shwing through. I know I could just use a single layer of backing, but the offcuts need to be used somewhere!

Im guessing its the difference in clarity between the two resin systems. Where the backing layers overlap, the part is slightly thicker there, creating a resin build-up. Another part was cooked at the same time alongside it with the same layup yet that one doesn't show this effect.

Forgot what the cooking times were the first time. This time it was 65 for 1 hour, 75 for 10 hours. Using VTF261 and PRF 464.


I've edited the photos by upping the contrast to highlight the effect. In real life its a bit less noticeable.




You can clearly see the corresponding lines that came through from the backing: