sealing a split mould

Talk Composites - The Forum for Advanced Composites

Back

sealing a split mould

Author	Message
FLD	FLD posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 2.7K	Fantastic, thanks for the suggestion and the advice. Testing would be a good idea given it's not my mould!
	Reply Like 3
Fasta	Fasta posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 3.5K	A paint primer can spray much thinner than a gelcoat so it saves weight, plus an easy prep for topcoating when all you need is a light wet/dry paper or even just a scotchbrite pad plus appropriate prep-sol or other to ensure there is no contamination issues or fish eyes with your top coat. You should really just do your own tests to confirm what is safe for release from your mould (or other test mould). Maybe an epoxy base primer? I know Gurit do a specific in mould primer. I would still test any new material when it comes to release, coat-ability etc. It's good practice. FLD (18/05/2016) Quick Q. What in mould primer would you guys recommend? I've never used them before and would default to a gelcoat. Fastacraft Facebook page
	Reply Like 3
FLD	FLD posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 2.7K	Quick Q. What in mould primer would you guys recommend? I've never used them before and would default to a gelcoat.
	Reply Like 3
FLD	FLD posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 2.7K	Thanks guys, I appreciate your help. FWIW its clamshells for a VX220 / Opel speedster.
	Reply Like 3
Hanaldo	Hanaldo posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	If you're going to paint it then I would definitely use an in-mould primer as Fasta suggested. And then certainly laying glass over the split lines will make sealing a non-issue. It's really only cosmetic carbon applications that make it difficult.
	Reply Like 3
Fasta	Fasta posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 3.5K	If you are painting it anyway then you could consider spraying the moulds with a primer instead. Then just use a tissue across the split lines to be sure. Painting composite parts that have no in mould coating or gelcoat will often still have surface pin holes to some extent and then also the issues you get with trying to paint a pinhole surface. You may need to wipe the mould seams with some wax or fillet wax so that they will also spray over well, if spraying. Fastacraft Facebook page Edited 9 Years Ago by Fasta
	Reply Like 2
FLD	FLD posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 2.7K	My thought was just a stripe of gelcoat over the seam. I could gel and tissue the seam but my plan was definitely not to gel coat the whole thing. Maybe I should just bag the whole lot and infuse or vac-bag and deal with the pin holes. It'll be painted anyway.
	Reply Like 3
Fasta	Fasta posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 3.5K	As long as you are gel coating and putting down a light CSM skin before infusion the split lines are no problem at all. Fastacraft Facebook page
	Reply Like 3
Hanaldo	Hanaldo posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	Gelcoat definitely doesn't seal them. Silicone gasket is the only somewhat reliable seal I have ever found. I say somewhat, because it doesn't always work. I've tried sealant tape along the outside edge of the flanges as well, but never had luck with that one.
	Reply Like 2
FLD	FLD posted 9 Years Ago HOT Topic Details
Group: Forum Members Posts: 468, Visits: 2.7K	I've been offered the use of a split mould to make a clamshell for my car. Seems rude not to! However, its a large split mould with no sealing channels in the flange. It got me thinking....... Can I seal over the split line with a compatible gel coat prior to infusion or is the gel coat stripe likely to let air by? I'd be grateful for any other suggestions too. Thanks all.
	Reply Like 2