Mould ruined after 1st use..

Talk Composites - The Forum for Advanced Composites

Back

Mould ruined after 1st use..

Author	Message
carbon man	carbon man posted 4 Years Ago HOT Topic Details
Group: Awaiting Activation Posts: 86, Visits: 1.2K	Hi, this mould is made from high temp epoxy and oven for 17 hours following the data sheet. I think I could of took more care in mould prep which didn't help. But it had about 8 coats of easy lease and struggled to out. Now the mould has carbon print through and cracked gel? Carbon use xpreg xc110 oven cured following standard curing cycle. Edit : carbon was in the mould over night before going in the oven as it was getting late and could fix leak in the bag. Edited 4 Years Ago by carbon man
	Reply Like 3
Chris Rogers	C Chris Rogers posted 4 Years Ago HOT Post Details
C Group: Forum Members Posts: 120, Visits: 933	That's a total bummer! The print into the mold is not abnormal - release systems generally work better on shiny surfaces - at a micro level there's less overall surface area with no scratches. This kind of thing can usually be buffed out or removed with mold cleaner. The cracks are concerning though! How thick is the carbon mold? The cracks look like they are caused by the mold shell being too thin and the stuck part and the violence required to finally remove it caused cracks as the mold shell flexed and the surface coating couldn't take it. It might help if you could share more pictures and details of the mold and part layup... Leaving the carbon in the mold under vacuum overnight shouldn't be an issue with pre-preg - it can really only help - unless I'm missing something!
	Reply Like 4
carbon man	carbon man posted 4 Years Ago HOT Post Details
Group: Awaiting Activation Posts: 86, Visits: 1.2K	+x Chris Rogers - 6/28/2020 3:02:59 PM That's a total bummer! The print into the mold is not abnormal - release systems generally work better on shiny surfaces - at a micro level there's less overall surface area with no scratches. This kind of thing can usually be buffed out or removed with mold cleaner. The cracks are concerning though! How thick is the carbon mold? The cracks look like they are caused by the mold shell being too thin and the stuck part and the violence required to finally remove it caused cracks as the mold shell flexed and the surface coating couldn't take it. It might help if you could share more pictures and details of the mold and part layup... Leaving the carbon in the mold under vacuum overnight shouldn't be an issue with pre-preg - it can really only help - unless I'm missing something! The mould lay up was 1 x thin gel 1 x thicker gel 1 x 200g carbon 6 x 450g carbon 1 x 200g carbon All layed on tacky stages Cracks possibly from the struggle of getting the carbon out? Lots of pulling and wedging. Carbon actually came out in two bits!
	Reply Like 4
Hanaldo	Hanaldo posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	How accurate were you with your mix ratio when you made the mould? It does look/sound like an under-curing issue. I've had similar before and realised I had used the wrong mix ratio. The mould cured hard enough that I didn't notice anything was wrong, but was obviously still very open to bonding. Could also simply be a release failure as well though. Is that surface finish the finish you wanted on your mould, or did it dull off during the cure? If it dulled during the cure then I would say it's an under curing issue for sure.
	Reply Like 4
carbon man	carbon man posted 4 Years Ago HOT Post Details
Group: Awaiting Activation Posts: 86, Visits: 1.2K	+x Hanaldo - 6/28/2020 10:17:13 PM How accurate were you with your mix ratio when you made the mould? It does look/sound like an under-curing issue. I've had similar before and realised I had used the wrong mix ratio. The mould cured hard enough that I didn't notice anything was wrong, but was obviously still very open to bonding. Could also simply be a release failure as well though. Is that surface finish the finish you wanted on your mould, or did it dull off during the cure? If it dulled during the cure then I would say it's an under curing issue for sure. Yeah all ratios weighed out and mixed properly, and yeah the mould was dull I was ok with that because it was getting clear coated. Next time I might make mould glossy to help with release
	Reply Like 3
Fasta	Fasta posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 3.5K	Did you use any sealer before the easylease? Fastacraft Facebook page
	Reply Like 4
carbon man	carbon man posted 4 Years Ago HOT Post Details
Group: Awaiting Activation Posts: 86, Visits: 1.2K	+x Fasta - 7/1/2020 8:02:25 AM Did you use any sealer before the easylease? No? Just mould cleaner
	Reply Like 4
Fasta	Fasta posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 3.5K	Using the sealer is just one more layer of insurance in the whole process. I imagine there is one as all semi permanent release systems seem to have one and they are recommended in their application instructions. The major enemy in moulds is often that they may not be cured properly, simply a slightly uncured mould material will then try to bond with the new part being made. By this rational an old mould could be the best for release while new moulds are far more likely to have a stickup. https://www.rexco-usa.com/why-molds-stick/ For pre preg moulds I will also run the mould through the full temp cooking cycle for some extra curing before using it for the first part. manufacture. Fastacraft Facebook page
	Reply Like 3
Hanaldo	Hanaldo posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	Easylease is a one part system, it's sealer is 'built in' to the release agent so it doesn't need a seperate sealer initially. In all honesty, there are so many possibilities for what could have caused this that without knowing exactly how the mould was made and everything that went on; we are all just speculating and you won't get an actual answer. For me, it looks like the mould wasn't fully cured. It is what I would expect to see if you tried to make a pre-preg part in a mould that hadn't been post cured first. There's a few things that could have caused that to be the case. Or I could be wrong, and it could be something else. Edited 4 Years Ago by Hanaldo
	Reply Like 3
oekmont	oekmont posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 550, Visits: 27K	This looks quite unusual for me. The only time epoxy gelcoat really cracks like that is if the mould flexed to much under excessive force. With such a small mould and >3000g/m^2 carbon reinforcement this seems unlikely. There are two things I can say with certainty: -There is something wrong with the gelcoat. Properly tempered there should not be any texture print. My best guess is the mixing ratio. To get this clear: I have never ever seen a bad charge of epoxy. problems were always caused by the user or a resin clogged scale. -the sides of the mould really ask for trouble with mechanical lock. IF the gelcoat was not mixed properly, the laminating resin might be mixed wrong too. This might make the mould flexible enough to crack the gelcoat.
	Reply Like 2