Engine bay covers in C/F which resin handle heat

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#1

Which products west system, fiber glast etc. I did a test piece with West Systems in my daily driver and its starting to yellow. No UV clear coat. Its purely a cosmetic piece. I’m assuming its the heat since the hood is closed 99.9999% of the time

Thanks for the help.

Greg

#2

Tried searching but could come up with and good key work that hit the question. Heat, discoloring,

found one for yellowing.

I do have clear polyester from fiber glast. Guess I could use that. but, what about the heat?
http://www.compositescentral.net/showthread.php?t=6856&highlight=yellowing

#3

I have used the US Composites Vinylester 700 series, and that claims its stable up to 700 degrees F, but I have never used it in a high heat application.

#4

700f for a VER?!?! That seems wrong. Most epoxies cannot handle that service temp, most thermoplastics can’t even handle that!!!

But back to the main point. You need to get a higher service temp resin. I would not expect a PER to survive long under heat.
I need to hook up my temp recorder under my hood and finally get some #'s for yall! Exhasut gas too!

#5

normal west isn’t that great for heat resistance. Search the datasheets, Tg is roughly the heat resistance (Glass transition temp, after that the resin gets rubbery and print etc will show)
You probably will need to do a post cure, bake the resin to build up the Tg to the optimum.

#6

do you used ortho polyester or iso polyester.? iso is better at heat resistance…

#7

Thanks for the tips. I 'm still testing the idea of clear polyester. The WS is to low.

#8

We use vinyl Esters on aircraft cowlings which see high temps from the exhaust stacks.

#9

Thanks guys!

#10

I would try a high temp clear epoxy such as HTR212-386 from Resin Services. It can withstand 375f without a post cure. Your other best bet is to sand the part down carefully removing the surface resin and careful not to sand into c/f. Use 220 paper. Then spray 2k automotive clear acrylic urethane.

P.s. clear polyester will yellow from heat.

#11

Just thinking out loud here… but would that really solve the problem of a resin that can’t handle the heat? The part would still get hot and the part would distort? Or do you just suggest that to try an salvage the existing part?

#12

Yeah I would think that would be more of a band aid fix more than a solution to the issue at hand.

#13

I’m kind of confused as to why i feel the need to defend my post… but here goes.
The sanding and clear coat is a faster and less expensive way to make the current bracket look good/better. He said he used West Systems epoxy… should be plenty durable enough for an underhood bracket so long as its isolated by a spacer from the cylinder head and engine block. Yellowing is going to happen no matter what resin is used. All resin yellows, some faster than others.

#14

Fastr, if the original part is failing due to the temps, adding a coat on top isn’t going to help protect it. It will make it look nice for a bit, but it’s still hot in the bay, and the entire part will soak in the heat, isolated or not. The only way to make it so the part stays perfect, is use a high-temp service resin…from the start.

#15

will a Clear coat help from the yellowing from the heat?

#16

Thanks for the info. Still gathering info, so the more the better. Trying not to waste any more $$$$$$$$$$$