Fibreglass over PLA - Heat and warping? Alternatives?

[Shryyyk]

I'm working on a helmet which has been printed in multiple pieces (PLA - should have done it all in PETG for easier sanding but live and learn...). As i've assembled it, it's shown up some gaps from both alignment drift (it was 24 separate pieces so that was bound to happen) and some slight warping due to the thickness of each piece. I'm planning on doing a UV resin top coat, both inside and out, ala Galactic Armory's method, to allow me to finish it more easily, but I want to put in some internal structural support before I do that.

The pieces are attached with thick superglue which seems to be holding nicely, but I definitely wouldn't want to drop it at this stage. I'm considering doing a couple of layers pass of fibreglass on the inside only (I have 300g on hand), but i'm slightly worried about the heat from the cure causing issues with the PLA.

Anyone have any experience with this? I've done a test piece which seemed OK but I'm not sure if I'm tempting fate. It's about a 100hr print at this point so I'd hate to ruin it.

Alternatively, any other suggestions? I had thought maybe duct tape on all joints and then straight resin to seal (no glass). I want to avoid doing anything dimensional on the outside of the helmet in case I lose detail, but happy to throw anything at the inside. Slush bondo somehow?

 

[Deetz]

The resin won't cause enough heat to warp the PLA, it's quite sturdy. One or two layers of fibreglass to the interior should be plenty to provide the support you need.