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Massimiliano
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Hi, I made my first part out of my first mould. 99% released fine but for some small areas where the tooling gelcoat merged with the gelcoat, please see pics. I need your expert advise to understand what I did wrong not to repeat. Mould made on Sunday, removed from pattern on Monday. Left to rest until Thursday. On Thursday, compounded with nw1 and polished with topfinish2. Cleaned 2 times with ec mold cleaner. One additional cleaning with acetone. 6 passes of Easy Lease every 15 mins 2 additional passes of miracle Gloss framed 15 mins Left overnight to rest On Friday two layers of white gelcoat framed one hour then hand layup with polyester laminating resin. Demolded after 24 hours. It released pretty fine (with a bit of compressed air) but for the spots. Any clue about what happened? I think it is almost impossible I missed 6+2 times just those few spots... Thanks a lot      
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Hojo
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1. Your gel coat looks too thick. Should be kept less than 0.5mm thick to avoid cracking and chipping. 2. If PE/VE gelcoat styrene could still be present, which affects the release ability. 3. Dont use acetone, stick with mould cleaner, though I doubt this is your issue. 4. Always seal the mould surface several times before using a release agent. This seals microporisty in the mould surface.
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Massimiliano
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Group: Forum Members
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+x1. Your gel coat looks too thick. Should be kept less than 0.5mm thick to avoid cracking and chipping. 2. If PE/VE gelcoat styrene could still be present, which affects the release ability. 3. Dont use acetone, stick with mould cleaner, though I doubt this is your issue. 4. Always seal the mould surface several times before using a release agent. This seals microporisty in the mould surface. Thank you! What mold sealer would you recommend? I can't find one in the EC website
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Hojo
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I am guessing easy composites has a sealer, I have not used before. Frekote or chemtrend are both good brands otherwise. Seal your mould 2 to 3 times before moving on to release. Also dont forget to post cure your mould before putting it in to service. Your Tg will be low, and properties not achieved unless you post cure accordingly.
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Massimiliano
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Group: Forum Members
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+xI am guessing easy composites has a sealer, I have not used before. Frekote or chemtrend are both good brands otherwise. Seal your mould 2 to 3 times before moving on to release. Also dont forget to post cure your mould before putting it in to service. Your Tg will be low, and properties not achieved unless you post cure accordingly. Thank you!
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oekmont
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I think the problem was not the little porosity a mould sealer would be able to seal. Your mould is full of small open air pockets. The closeups show many white pieces of gelcoat stuck in the tooling gelcoat, as well as goosebumps on your final part. The edge of your mould doesn't look good either. There were a lot of mechanical loking points. Some of them were too much for the tooling gelcoat. My guess is that you moulded from a bad plug und sanded the mould a lot, right? If so, always try to make the plug as perfect as possible. Sanding the mould too much is always the risk of opening some air bubbles in the tooling gelcoat.
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Hojo
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+xI think the problem was not the little porosity a mould sealer would be able to seal. Your mould is full of small open air pockets. The closeups show many white pieces of gelcoat stuck in the tooling gelcoat, as well as goosebumps on your final part. The edge of your mould doesn't look good either. There were a lot of mechanical loking points. Some of them were too much for the tooling gelcoat. My guess is that you moulded from a bad plug und sanded the mould a lot, right? If so, always try to make the plug as perfect as possible. Sanding the mould too much is always the risk of opening some air bubbles in the tooling gelcoat. A good point, its probably a void under the gelcoat. Often when you hand laminate without vacuum you will get a void from the material bending around a corner. You can add a mix of resin and cabosil and put this around the edge to help avoid these types of voids. You can also do a thin fiberglass skin on the gelcoat and inspect for voids after it cures. If you see any voids you can cut them open with a knife and they will fill with the second round of lamination. This is why I prefer infusion or prepreg/autoclave for tools. Quality is superior in so many ways to hand lamination.
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Massimiliano
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Group: Forum Members
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+xI think the problem was not the little porosity a mould sealer would be able to seal. Your mould is full of small open air pockets. The closeups show many white pieces of gelcoat stuck in the tooling gelcoat, as well as goosebumps on your final part. The edge of your mould doesn't look good either. There were a lot of mechanical loking points. Some of them were too much for the tooling gelcoat. My guess is that you moulded from a bad plug und sanded the mould a lot, right? If so, always try to make the plug as perfect as possible. Sanding the mould too much is always the risk of opening some air bubbles in the tooling gelcoat. You have acute and expert eyes! Yes my plug was not prefect and when I covered it with tooling gelcoat, probably some micro cracks in the hi gloss pattern coat let styrene eat a little of the xps foam, this led to an irregular border in some spots. I did not sand the mould at all. The chipping occurred on smooth corners, I think this is due to not fully cured mold... When I removed the tooling gelcoat spots from the part with a small blade, it came off almost perfectly but very tiny spots where instead it was welded. Probably as Hojo suggested I should have waited more before using it, or put it in a oven to reach full properties... or both!
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Massimiliano
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Group: Forum Members
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+x+xI think the problem was not the little porosity a mould sealer would be able to seal. Your mould is full of small open air pockets. The closeups show many white pieces of gelcoat stuck in the tooling gelcoat, as well as goosebumps on your final part. The edge of your mould doesn't look good either. There were a lot of mechanical loking points. Some of them were too much for the tooling gelcoat. My guess is that you moulded from a bad plug und sanded the mould a lot, right? If so, always try to make the plug as perfect as possible. Sanding the mould too much is always the risk of opening some air bubbles in the tooling gelcoat. A good point, its probably a void under the gelcoat. Often when you hand laminate without vacuum you will get a void from the material bending around a corner. You can add a mix of resin and cabosil and put this around the edge to help avoid these types of voids. You can also do a thin fiberglass skin on the gelcoat and inspect for voids after it cures. If you see any voids you can cut them open with a knife and they will fill with the second round of lamination. This is why I prefer infusion or prepreg/autoclave for tools. Quality is superior in so many ways to hand lamination. You mean applying by hand the tooling gelcoat and then infuse the reinforcement? Will not the vacuum deform the thin gelcoat where the plug is filleted with the filleting wax?
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Hojo
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Group: Forum Members
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+x+x+xI think the problem was not the little porosity a mould sealer would be able to seal. Your mould is full of small open air pockets. The closeups show many white pieces of gelcoat stuck in the tooling gelcoat, as well as goosebumps on your final part. The edge of your mould doesn't look good either. There were a lot of mechanical loking points. Some of them were too much for the tooling gelcoat. My guess is that you moulded from a bad plug und sanded the mould a lot, right? If so, always try to make the plug as perfect as possible. Sanding the mould too much is always the risk of opening some air bubbles in the tooling gelcoat. A good point, its probably a void under the gelcoat. Often when you hand laminate without vacuum you will get a void from the material bending around a corner. You can add a mix of resin and cabosil and put this around the edge to help avoid these types of voids. You can also do a thin fiberglass skin on the gelcoat and inspect for voids after it cures. If you see any voids you can cut them open with a knife and they will fill with the second round of lamination. This is why I prefer infusion or prepreg/autoclave for tools. Quality is superior in so many ways to hand lamination. You mean applying by hand the tooling gelcoat and then infuse the reinforcement? Will not the vacuum deform the thin gelcoat where the plug is filleted with the filleting wax? no, when I do infusion tools I do not use gelcoat. If you want to use gelcoat and infuse, typically you need to put down a skin layer down, typically fiberglass so you can see air bubbles
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