Making a prepreg carbon front clip for my Lotus Elan. So far so good.



Mould with the reinforcement that caused the problem. I bagged the whole thing. This resulted in a differential pressure between the inner surface and the outer skin under the reinforcement which resulted in the mould sinking under the pressure!

It's an interesting mould, but in my opinion that ribbing structure is totally unnecessary as well. That mould would be plenty stiff just from those parting barriers.

Anyway, I agree with oekmont - the pressure differential isn't the cause of the print. If it was, the mould surface would have blistered outwards, not collapsed inwards. And even this would have been extremely unlikely unless the mould is only one or two mm thick - a regular thickness mould of 5-6mm would quite easily withstand that pressure differential.

Unless of course, as oekmont mentioned, the mould couldn't handle the temperature. Whether that's due to too low a Tg, or just not having had a good enough post-cure prior to attempting this cure. I'd say this is almost certainly temperature related.