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In mould clear coat sinking into fibres?


TCook

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Bit of a weird issue I’ve come across. I have sprayed a 2k general automotive clear coat into the mould before laying up. Infused it and took out the part and it looked great. However after a day or two it looks as if the clear coat has almost sunk into the fibre gaps giving it a strange texture. I have tried to take photos but it is a very small detail so I hope you can see it. It is all over the part not just in the photoed areas. I have also had the same issue with a polyester gel coat I used previously. The more scratched image is the much thicker gel coat and the less scratched is a much thinner 2k clear coat. 
 

any ideas as to why this is and how to stop it? I could maybe understand if the gel coat one got too hot in the sun or just ambient temps of 25-30°c but I would think the much harder automotive clear coat wouldn’t budge. 

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On 8/10/2024 at 11:03 AM, TCook said:

Bit of a weird issue I’ve come across. I have sprayed a 2k general automotive clear coat into the mould before laying up. Infused it and took out the part and it looked great. However after a day or two it looks as if the clear coat has almost sunk into the fibre gaps giving it a strange texture. I have tried to take photos but it is a very small detail so I hope you can see it. It is all over the part not just in the photoed areas. I have also had the same issue with a polyester gel coat I used previously. The more scratched image is the much thicker gel coat and the less scratched is a much thinner 2k clear coat. 
 

any ideas as to why this is and how to stop it? I could maybe understand if the gel coat one got too hot in the sun or just ambient temps of 25-30°c but I would think the much harder automotive clear coat wouldn’t budge. 

IMG_9276.jpeg

IMG_9274.jpeg

You sprayed clear coat into the mold and then did the layup?

Usually, you do that after. That might be your problem right there 😄

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Done it plenty times before with no issue. The part comes out of the mould perfect then after a few days it will lose its flat/smooth surface. I believe this is due to the part not fully curing when in the mould and then still being slightly malleable before it cures fully. I need to do more testing with curing times in the oven and it should be sorted. 

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1 hour ago, TCook said:

Done it plenty times before with no issue. The part comes out of the mould perfect then after a few days it will lose its flat/smooth surface. I believe this is due to the part not fully curing when in the mould and then still being slightly malleable before it cures fully. I need to do more testing with curing times in the oven and it should be sorted. 

Sounds like the paint is contaminating the resin/prepreg. Try doing this clear coat during layup, prepping, sanding, and coating.

I'd bet you'll come out with much better parts 👍

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