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wochi
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the pinholes are barely visible at naked eye so i think they wont be a problem in the future. I´m not talking about massive pinholes. Like i said before they are barely visible. They will only show up when i apply the lacquer
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Hanaldo
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Gelcoat doesn't ACTUALLY fix the pinholes though, they are still there underneath the gelcoat. And quite often, the part comes out of the mould nice and perfect and everyone is happy, but once the part has been in use for awhile or sees some heat cycles or strangely enough just exists for a bit of time, the gelcoat can start to blister away at the pinholes as they are unsupported voids. So down the track, you can end up with a part that is full of pinholes again. This is why I say it's better to fix the actual issue, as there must be one.
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wochi
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Never tried that as like you said it´s not supposed to work like that. But can give it a shot. At this point i can only see beeing some oil/moisture passing through the filters and going to the gun. I will do a test using a brush to actually rule out if this is the problem. If it´s not I´m out of ideas. What kind of setup do you use with your compressor? As for the problem beeing connected with the pinholes i really doubt. I tested million of different methods and none could make a flawless infusion. But at this point i would be happy with the gel coat working properly as it fixed the pinhole problems and the parts came out perfect (except for the milky thing)
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Hanaldo
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Well there's an issue somewhere along the line, as it's certainly possible (and very easy in fact, once everything clicks together) to get 100% perfect pinhole free results from infusion with no coatings. Actually that makes me wonder if perhaps the two issues are linked. It seems unlikely, but it's possible in the wonderfully complex world of composites. Have you tried spraying the GC50 post-mould? I know it's not intended for that function, but you could see if it goes cloudy after simply spraying it or whether it has something to do with your process.
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wochi
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I tryed both ways. Making a very thick coat and a very thin coat. I have measured the thickness and it was 0.3mm on the second try. Catalyst is a couple of months old. From a local supplier as EC doesn´t ship this product overseas and had no problems before with it. My last try will be doing a brush aplication so i can rule out moisture on the spray gun. Although it seams very unlikely to be the problem. As for the pinholes i gave up on trying to get them all out. No matter how i hard i try i allways get them. Even demoulding most of the parts seem perfect but if you do a close inspection you seem them and they show up pretty nasty when i´m applying the clear coat. I tryed all. I degass, i pre heat the resin, i make vaccum drop tests, everything i could find i tried. Never had a perfect part with absolutly no pinholes.
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Warren (Staff)
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Thicker gelcoats will reduce in clarity for sure. Also it looks like the orangy GC50 is pretty old, perhaps some of the styrene has dried out since you last used it?
It is strange you are still getting milkyness with the new material which kind of rules out the old material being at fault due to age so something else is clearly going on here. Maybe thickness, humidity? contamination when spraying? (eg oil and moisture through compressor is a common one)
Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
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Hanaldo
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Personally I think solve the problem as to why you are getting pinholes, coatings are just a bandaid fix. But that's not really very helpful. Can you perhaps measure your gelcoat thickness? I'm not sure how sensitive the GC50 is to thickness (Warren?), but I know some gelcoats need to be pretty spot on 25 micron. Perhaps your issue is not thick enough rather than too thick, leading to undercuring of the gelcoat? I sort of doubt that though. How about catalyst, can you rule out catalyst being an issue? How old is it, what level are you catalysing at? Do you get your catalyst from EC or another supplier?
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wochi
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did another part with the new GC50 and the problem is still there! It´s perfectly noticable from certain angles the "milky" coat. Don´t know what else to do. Any other product that can be sprayed and used as a gelcoat for epoxy infused parts? I really liked the solution as there are no pinholes so the part doesn´t require too much work after coming out of the mould
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wochi
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 upside down but you get the point. Can this be the problem? GC50 beeing too old? How can i see the production date?
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Warren (Staff)
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Very strange. Perhaps it had started to dry out? We sell a large amount of GC50 each month so the stock is always fresh and doesn't spend long on the shelf.
A photo next to each other would be a useful comparison.
Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
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