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Tominator
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Is that the PRF material?
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morepower
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Here is a part I made yesterday which is straight out of the mould and only been trimmed up.. No lacquer on here yet... It is not easypreg or VTF261 and shows you can get perfect parts if you do everything correctly... It is a test in an old mould so it is not the best mould to use and it is only a general purpose resin that was used to make it.. But it is a good test and proves perfect parts can be made with no pinholes even without easypreg or VTF261. 
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carboncactus
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cpkielycua (26/08/2013)
I have perfected my use of the surface and backing layers of your prepreg, but see room for improvement. Even with the highest continuous run vacuum there are still some pinholes. If you are getting pinholes, you haven't perfected it. Have you tested your vacuum? Done a 30 min drop test? Slow ramping? You shouldn't get any pinholes whatsoever if you got the process nailed.
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morepower
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cpkielycua (27/08/2013)
Do you use a perforated release film or non perf?Non Perferated Do you run the surface layer up the flange and stop the backing layer shorter on the flange? I run both to the flange, this is a requirement of the part, how does this effect? Do you run peel ply under the surface layer on the flange? Not sure what you mean, I use the surface layer, plus two of the ~200 backing layer to the flange with non perf peel ply and a mesh plastic breather between the peel ply and the mold bladder. I have noticed the mesh attracts some epoxy, for this to happen, the epoxy would have to flow a good 5 inches. From the layup, up the sidewall to the flange, over the layup, down the back side of the peel ply and to the center of the part. It is a bit perplexing how thats possible; although my pump gets very high pressure, and I am at about 6 feet above sea level. Do you de-bulk after laying the surface layer? No, I use a roller and a small "squeegee" type piece of plastic, I run the surface layer and mold under the A/C to cool both so I have the flexibility to lay/ reposition, and remove any air bubbles without distorting the surface layer. I really dont have any voids or air bubbles, just pin holes. My finished part is high glossy right out of the mold just like your pic above; these are really small pin holes (prob not visible in a photo) but there nonetheless. A clearcoat in mold (preferred) or spray clearcoat after may also solve the problem, but I have not figured out the best method/product for UV clear coat. Obviously I prefer in mold like others have commented on the site. How long do you leave the finally laid up part in the vacuum to de-bulk before cooking it???
I really dont de-bulk, with only the 3 thin layers and no obvious issues. I think if there is any root cause/problem, its the epoxy travel due to the very high pressure. I hesitate to think I should reduce the pressure, but still need to solve the problem.
If I do end up solving the (micro)pinhole problem, I am still looking for the sacrificial wet sand/polish layer. OK.... You need to run only the surface layer over most of the flange of the mould and the backing layers 10mm shorter or just up to the flange. You also need to put a strip of peel ply under the carbon that is on the flange area only too...(between the flange and the material and do this round the whole flange on the mould. I use a 50mm wide peel ply strip.) I dont run a gel coat in the mould and think it may actually hinder the material you are using rather than help. You need to de-bulk the carbon in the mould. If it is only 2 or 3 layers thick you can lay up the whole part and bag it. But you need to allow it to be pulled down in a full vacuum for at least a couple of hours or longer.. I leave it over night with a full vacuum. I use a none perf with a breather cloth over the top only... No mesh and no peel ply apart from on the flange ONLY. I put breather cloth over the release film then over the whole mould back too.. We are about 200 feet above sea level.. Nothing in the greatest scheme of things... I dont have pinholes over my parts unless I have made a mistake when I lay up ... Adding UV stabilisation alters the chemistry of the resin and none of the epoxy resins used in pre-preg as far as I know are UV stable. Some are better than others but ALL of them yellow over time. A 2k lacquer is the best thing to get a good gloss... Here is mine with a quick coat of lacquer from a cheap rattle can and not even a good 2k lacquer..   If you have pin holes at all you have not perfected using the material... It will have to be sprayed to get the best surface gloss that is UV stable.. But you can get a very VERY good gloss surface in a good mould if you wanted too... But cannot say how long it would take to discolour... it could be months or years... but it will not be UV stable..
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cpkielycua
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Although if I find a good in mold UV epoxy clearcoat, I may not need the prepreg sacrificial layer. Obviously alot of folks have this problem, why can a UV additive not be included with the prepreg, is it a chemical formulation issue? It has to be a difficult problem to solve, because everyone wants it but it is not available. It'd be interesting to understand why this is the case.
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cpkielycua
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Group: Forum Members
Posts: 29,
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Do you use a perforated release film or non perf?Non Perferated Do you run the surface layer up the flange and stop the backing layer shorter on the flange? I run both to the flange, this is a requirement of the part, how does this effect? Do you run peel ply under the surface layer on the flange? Not sure what you mean, I use the surface layer, plus two of the ~200 backing layer to the flange with non perf peel ply and a mesh plastic breather between the peel ply and the mold bladder. I have noticed the mesh attracts some epoxy, for this to happen, the epoxy would have to flow a good 5 inches. From the layup, up the sidewall to the flange, over the layup, down the back side of the peel ply and to the center of the part. It is a bit perplexing how thats possible; although my pump gets very high pressure, and I am at about 6 feet above sea level. Do you de-bulk after laying the surface layer? No, I use a roller and a small "squeegee" type piece of plastic, I run the surface layer and mold under the A/C to cool both so I have the flexibility to lay/ reposition, and remove any air bubbles without distorting the surface layer. I really dont have any voids or air bubbles, just pin holes. My finished part is high glossy right out of the mold just like your pic above; these are really small pin holes (prob not visible in a photo) but there nonetheless. A clearcoat in mold (preferred) or spray clearcoat after may also solve the problem, but I have not figured out the best method/product for UV clear coat. Obviously I prefer in mold like others have commented on the site. How long do you leave the finally laid up part in the vacuum to de-bulk before cooking it???
I really dont de-bulk, with only the 3 thin layers and no obvious issues. I think if there is any root cause/problem, its the epoxy travel due to the very high pressure. I hesitate to think I should reduce the pressure, but still need to solve the problem.
If I do end up solving the (micro)pinhole problem, I am still looking for the sacrificial wet sand/polish layer.
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morepower
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cpkielycua (26/08/2013)
I'll keep working on the pinholes, but still require a different product for the other above reasons. Other than a new product from Easy Composites, my plan is to buy the epoxy film and adding it to the backing layer.There are other pre-pregs off the shelf with up to about 60% resin content. I use one and it is a good material but I cannot say if it is compatible with the material you are using. It is a good material but there are pinholes with it even though there are less than many of the others I have tried...
Are you using a perf release film? Even with the 41 or 42% resin content a perforated release will push some exess resin through the perforations so more resin is not going to do a lot..
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cpkielycua
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Group: Forum Members
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I'll keep working on the pinholes, but still require a different product for the other above reasons. Other than a new product from Easy Composites, my plan is to buy the epoxy film and adding it to the backing layer.
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morepower
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cpkielycua (26/08/2013)
I have perfected my use of the surface and backing layers of your prepreg, but see room for improvement. Even with the highest continuous run vacuum there are still some pinholes. Also Id like to have a slight buffer to be able to wet sand and polish after molding. Lastly the stray fiber from the surfacing layer can ruin the otherwise perfect surface. If you offered your standard prepreg backing layer with the 'surface layer film' on top it would be perfect. A very resin rich (even if not the perfect ratio) would solve all my layup issues. Essentially taking your backing layers and adding the film making it a double rich layer. This would solve the pinhole problem, the stray fiber problem, and the wet sanding allowance problem. Please let me know if you are able to carry, order, or modify from a supplier, Im sure it will be hit with many orders! The pre-preg Easy Composites use is the industries best OOA pre-preg. If you have pin holes you have not perfected your lay up. I use it but buy from the same source as Easy Composites and there is no better material. There are more resin rich carbons but they suffer from pin holes.. There are carbons with better clarity but suffer from pin holes. There are some that have higher tack when you lay up but again suffer pin holes.. This is the same material un-lacqured and straight out of the mould...  Do you use a perforated release film or non perf? Do you run the surface layer up the flange and stop the backing layer shorter on the flange? Do you run peel ply under the surface layer on the flange? Do you de-bulk after laying the surface layer? How long do you leave the finally laid up part in the vacuum to de-bulk before cooking it???
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cpkielycua
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Group: Forum Members
Posts: 29,
Visits: 285
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I have perfected my use of the surface and backing layers of your prepreg, but see room for improvement. Even with the highest continuous run vacuum there are still some pinholes. Also Id like to have a slight buffer to be able to wet sand and polish after molding. Lastly the stray fiber from the surfacing layer can ruin the otherwise perfect surface. If you offered your standard prepreg backing layer with the 'surface layer film' on top it would be perfect. A very resin rich (even if not the perfect ratio) would solve all my layup issues. Essentially taking your backing layers and adding the film making it a double rich layer. This would solve the pinhole problem, the stray fiber problem, and the wet sanding allowance problem. Please let me know if you are able to carry, order, or modify from a supplier, Im sure it will be hit with many orders!
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