We are trying to create carbon wing (see photos) from textrem with infusion, almost whole wing is ok, but last part, after few minutes on sun it goes wrong.

Can you please give us some hint, what we are doing wrong?

Hi

We are using resin ATLAC 590 (CAS-100-42-5). Yes, we are allowing enough time before de mould. No, we didn't do any post cure.

So I couldn't find a lot of information about the resin system, but I did find that it's styrene based so obviously vinyl ester or polyester. Is this a resin designed for infusion or vacuum bagging? If not, this might be your issue. Styrene based resins require the styrene monomer to cure properly, but under vacuum the styrene evaporates too quickly and doesn't let the resin cure fully. 

If this is happening on first exposure to the sun then simply you need to be curing the part for longer with a postcure. 

At room temperatures, many resins simply dont cure 100% straight away.  You may well be able to demould and trim but some uncured resin remains.  In the sun a black part can easily and quickly get to 40C and then at high as 60C even in moderate climates.  That will certainly make many a resin go soft causing the deformation you are seeing.

The solution is a postcure to ensure all the resin is fully cured upto any reasonable operating temperature, based on the Tg of the resin system.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant