Breaking in mould. Does anyone do it? My moulds stuck!


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carbon man
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So Iv had 3 moulds stick on me now. I'm using tr108 wax as it's advertised to reduce fish eye when gel coat goes into the mould.

I have tried exact instructions on tin 8 coats and then leave over night before another coat.

Also tried 5 chem release followed by 2 tr108 wax.

I brush in polyester gel coat let dry. Lay up and  infuse with epoxy In2 resin and cure in mould at 60deg straight away for about 8 hours so it gels fast in the event of a leak.

The shiney parts of the mould released just about but everywhere else stuck like s***!

But should I be laying in a layer of fibreglass and pulling that out once cured to break in mould first?

Any help appreciated.
Edited 4 Months Ago by carbon man
KLComposites
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carbon man - 6/16/2021 8:46:22 PM
So Iv had 3 moulds stick on me now. I'm using tr108 wax as it's advertised to reduce fish eye when gel coat goes into the mould.

I have tried exact instructions on tin 8 coats and then leave over night before another coat.

Also tried 5 chem release followed by 2 tr108 wax.

I brush in polyester gel coat let dry. Lay up and  infuse with epoxy In2 resin and cure in mould at 60deg straight away for about 8 hours so it gels fast in the event of a leak.

The shiney parts of the mould released just about but everywhere else stuck like s***!

But should I be laying in a layer of fibreglass and pulling that out once cured to break in mould first?

Any help appreciated.

You might be seeing high exotherm and temperatures over what the wax is rated for. Data sheet says the TR108 good to 85C but if you're throwing it in the oven at 60C immediately, your resin might get pretty toasty. 

Try Rexco's partall high temp wax. I had much better luck with it than the TR108. I was also seeing relatively high exotherm at moderate cure temps.


carbon man
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KLComposites - 6/18/2021 4:20:19 PM
carbon man - 6/16/2021 8:46:22 PM
So Iv had 3 moulds stick on me now. I'm using tr108 wax as it's advertised to reduce fish eye when gel coat goes into the mould.

I have tried exact instructions on tin 8 coats and then leave over night before another coat.

Also tried 5 chem release followed by 2 tr108 wax.

I brush in polyester gel coat let dry. Lay up and  infuse with epoxy In2 resin and cure in mould at 60deg straight away for about 8 hours so it gels fast in the event of a leak.

The shiney parts of the mould released just about but everywhere else stuck like s***!

But should I be laying in a layer of fibreglass and pulling that out once cured to break in mould first?

Any help appreciated.

You might be seeing high exotherm and temperatures over what the wax is rated for. Data sheet says the TR108 good to 85C but if you're throwing it in the oven at 60C immediately, your resin might get pretty toasty. 

Try Rexco's partall high temp wax. I had much better luck with it than the TR108. I was also seeing relatively high exotherm at moderate cure temps.


Thanks for the reply. I can't seem to find anywhere that sells that in the UK? 

Hanaldo
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carbon man - 6/16/2021 8:46:22 PM
I brush in polyester gel coat let dry. Lay up and  infuse with epoxy In2 resin 

I think this will be your issue. You can't use epoxy resin behind a polyester gelcoat, it won't bond properly. Gelcoats are designed to not fully cure, and they need the chemical reaction between the gelcoat and the laminating resin to cure and make a strong bond. Epoxy doesn't react chemically with polyester, it is a purely mechanical bond, and because the gelcoat isn't cured properly the mechanical bond strength is very poor.

So your issue probably isn't so much a release failure, but the fact that the surface tension between the gelcoat and the mould is higher than the bond strength between the gelcoat and the epoxy resin. 

Either switch to an epoxy gelcoat, or switch to a polyester/vinyl ester laminating resin.

carbon man
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Hanaldo - 6/19/2021 12:05:30 AM
carbon man - 6/16/2021 8:46:22 PM
I brush in polyester gel coat let dry. Lay up and  infuse with epoxy In2 resin 

I think this will be your issue. You can't use epoxy resin behind a polyester gelcoat, it won't bond properly. Gelcoats are designed to not fully cure, and they need the chemical reaction between the gelcoat and the laminating resin to cure and make a strong bond. Epoxy doesn't react chemically with polyester, it is a purely mechanical bond, and because the gelcoat isn't cured properly the mechanical bond strength is very poor.

So your issue probably isn't so much a release failure, but the fact that the surface tension between the gelcoat and the mould is higher than the bond strength between the gelcoat and the epoxy resin. 

Either switch to an epoxy gelcoat, or switch to a polyester/vinyl ester laminating resin.

Hi, some of my moulds that have had a couple of pulls are now fine and appear to have bonded to the Scott bader cystic gloss coat well? It's just on the new mould I'm having trouble.

Are you UK? I can't find vinyester infusion resin. Only at East Coast fibreglass but they say its not clear resin.

Thanks

Hanaldo
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Ah, that's different then - Crystic Glosscoat isn't a gelcoat, it does cure solid and epoxy can bond to it.

Breaking in moulds is definitely a thing. Though if you can get a semi-permanent tool sealer, then this will treat the chemical and physical bonding sites of a new mould in the same way that breaking them in does. So I never break in any of my new moulds, because they always get treated with a sealer first.
carbon man
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Hanaldo - 6/19/2021 3:07:21 PM
Ah, that's different then - Crystic Glosscoat isn't a gelcoat, it does cure solid and epoxy can bond to it.

Breaking in moulds is definitely a thing. Though if you can get a semi-permanent tool sealer, then this will treat the chemical and physical bonding sites of a new mould in the same way that breaking them in does. So I never break in any of my new moulds, because they always get treated with a sealer first.

Awsome glad to hear that because I love the gloss coat it dries smooth with no brush marks.

Have you had much experience with gloss coat? I guess it's a ok product to use as a clear coat. It seems to dry and polish up great

I have tried Tr102 wax took a bit of brushing with the gloss coat to remove fish eye but all looking good so far.

I think the problem is tr108 wax. It just doesn't leave my moulds smooth, almost a matt Finnish then they stick.

Edited 4 Months Ago by carbon man
Fasta
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When the new mould was made did it all cure really well? Gelocoat? and laminate? Correct temperatures etc?

Undercured cured moulds can often are recipe for a stickup regardless of release agents and application of them. 

https://www.rexco-usa.com/why-molds-stick/

I always use semi-permanent release agents and wax coats with wet layup moulds.







Hanaldo
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carbon man - 6/19/2021 8:11:50 PM
Hanaldo - 6/19/2021 3:07:21 PM
Ah, that's different then - Crystic Glosscoat isn't a gelcoat, it does cure solid and epoxy can bond to it.

Breaking in moulds is definitely a thing. Though if you can get a semi-permanent tool sealer, then this will treat the chemical and physical bonding sites of a new mould in the same way that breaking them in does. So I never break in any of my new moulds, because they always get treated with a sealer first.

Awsome glad to hear that because I love the gloss coat it dries smooth with no brush marks.

Have you had much experience with gloss coat? I guess it's a ok product to use as a clear coat. It seems to dry and polish up great

I have tried Tr102 wax took a bit of brushing with the gloss coat to remove fish eye but all looking good so far.

I think the problem is tr108 wax. It just doesn't leave my moulds smooth, almost a matt Finnish then they stick.



Yes I've used Glosscoat a lot, probably gone through a good 250kg in the last couple of years. It's OK, there are better products out there - I dont like how red it is, and it does change the colour of your finished part. Not the most noticeable thing, but it is noticeable.

Definitely sounds like there is an issue between your gelcoat and the TR108, I also use TR108 a lot and it certainly never leaves any sort of matte finish, so that's a bit strange.
carbon man
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Hanaldo - 6/22/2021 12:05:16 AM
carbon man - 6/19/2021 8:11:50 PM
Hanaldo - 6/19/2021 3:07:21 PM
Ah, that's different then - Crystic Glosscoat isn't a gelcoat, it does cure solid and epoxy can bond to it.

Breaking in moulds is definitely a thing. Though if you can get a semi-permanent tool sealer, then this will treat the chemical and physical bonding sites of a new mould in the same way that breaking them in does. So I never break in any of my new moulds, because they always get treated with a sealer first.

Awsome glad to hear that because I love the gloss coat it dries smooth with no brush marks.

Have you had much experience with gloss coat? I guess it's a ok product to use as a clear coat. It seems to dry and polish up great

I have tried Tr102 wax took a bit of brushing with the gloss coat to remove fish eye but all looking good so far.

I think the problem is tr108 wax. It just doesn't leave my moulds smooth, almost a matt Finnish then they stick.



Yes I've used Glosscoat a lot, probably gone through a good 250kg in the last couple of years. It's OK, there are better products out there - I dont like how red it is, and it does change the colour of your finished part. Not the most noticeable thing, but it is noticeable.

Definitely sounds like there is an issue between your gelcoat and the TR108, I also use TR108 a lot and it certainly never leaves any sort of matte finish, so that's a bit strange.

You say better products out there? Which do you recommend that can be brushed in mould and dry smooth with no brush marks? 

GO

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