Carbon fiber hood liner/ front air dam/coil cover

[azygoustoyou]

I finally got mine done. Doing so many things at once trying to make progress.
I put it on with a couple bolts but it has to come back off till other things are installed.

[blurple124]

Though this is an old thread that has been quiet for a few years now, I thought I would give my input.

You mentioned that you had a hard time with the vinyl ester resin releasing from the molds, were you using a vacuum bagging process? One big difference between vinyl ester and epoxy based resins is that epoxy is an anaerobic cure, meaning no oxygen is required-just cure it at a high temperature for better thermal resistance.

Vinyl ester, on the other hand, needs oxygen to cure. If you had sealed the resin and carbon in a vacuum bag, it would not have cured all the way except to the mold-release wax. Wax contains enough oxygen that some resin will cure to the mold and the wax rather than just to the carbon fiber, making it a "you know what" to get off.

One way around this is to use PVA mold-release agent, which sprays on as a film (you have probably heard of it), but sacrifices some finish, or to maintain the surface finish of wax and use epoxy resin, but baking it at higher temperatures for better properties.

It is obvious that you have already come up with a solution and the results look fantastic, but I figured it couldn't hurt to spread experience.

[azygoustoyou]

This thread isn't that old. Unless time and raced past me again. I didn't use a bagging system. I have the mold for the hood liner done. It's just it's stuck in my hood. So I turned it upside down so gravity might help. LOL
I never was able to get a good mold. I take that back. I did on the spoiler but wasn't able to get a good item out of it without having to work it. So I decided to do what I did as overlays. I will get one hood liner done no matter what for my car. After that I'm done. I am making one or two more spoilers some time soon. Thanks for your input.

[blurple124]

Oh my apologies! I was not looking at the right date!

One trick we used (though it makes it tough to reuse your mold) is to drill a shallow hole in an area where the carbon will not be used/doesn't need to be aesthetic, and stick an air compressor nozzle into it. Once you get an air pocket started it should pop right out, depending on what issues you might have had with the curing process.

Just curious, what weave of CF are you using?

[azygoustoyou]

I had to heat the liner to get it out of my hood. I'm just glad it came out. I don't know how I'm going to go about making the hood liner just yet. I'll either use my hood or the mold. I'll throw aluminum foil over it so I know it released. I put so much wax paste and even a PVA spray. It still took my paint off. I hope the hood is fine. I haven't really looked at it yet. I think it is.
Time to clean up the clay and go from there.

[azruss]

try using clear box tape instead of foil. you will get a much more user friendly surface on your glass. i used it on my bodywork to fit my ground effects. didnt even wax it up. didnt want to contaminate my primer. For the big surface you are applying, i would tape it and wax up the tape.

[azygoustoyou]

Thanks,
I was thinking of using the inside of the mold then turning it over to work the outside since it would have to be done as an overlay. I might just use the card board liner to make it. The orange mold is in really bad shape. I don't think it's useable.
I guess I better get to it soon though. It's starting to get cooler.

[azygoustoyou]

Update on my 2nd attempt to make a carbon fiber hood liner.
I took a good liner and laid it flat with the inside facing upward. I didn't coat it with anything. I started laying the fiberglass mat on top and covered it with resin. I let it dry some. I noticed it seemed to want to lift so I put on a second coat with more resin. I let it dry. I put on a third coat of resin with wax so it wouldn't be sticky. I let it dry about a day and half. It's real humid here now. The one side lifted nicely but the other side is sticking some so I turned it over and filled the sticking side with water to release it. So far so good. I should have tried this the first time. Once I get it out, I'll start working the inside with carbon fiber so it will face outward.

[azruss]

you're doing all that glass work on your deck. Man, you are a brave guy.

[azygoustoyou]

Yeah, last winter I did it in the kitchen. She didn't like that idea. I did it while she was at work.
I had to air the house out pretty good.

[blurple124]

What made you decide not to use gel coat this time?

[azygoustoyou]

It never comes out right with the gel coat and the surface I was taking the mold off wasn't very good (smooth).
I plan on putting two coats of carbon fiber then be done with it. I have to wait till it dries to get the rest of the old liner off. It's sticky now. I'll have to sand it off. It's exactly what I was after.

[manoa matt]

Brady, with all the work that goes into making a hood liner, why don't you just make a carbon fiber or fiberglass hood?

[blurple124]

Well I suppose you can get the glass smooth enough for that. You really don't need it to be a mirror finish anyway. I would say that dousing your fiberglass mold in a PVA mold releasing agent (instead of wax) like this: http://www.opentip.com/Sporting-Goods/F ... e=googleps

Then it will pop off for sure. I don't know what kind of carbon you have been using, but you will want to avoid the tri-axial weave for these curves. It just doesn't like to bend. The twill weave is very flexible and is meant for more aesthetically appealing looks, while the bi-axial is flexible enough but is much cheaper.

I have also heard things about pre-peg carbon. No layup time-limit (before the resin cures) and probably less mess. Although I think it requires a vacuum bag. Never used it though.

I can't wait to see how they turn out!

[azygoustoyou]

Brady, with all the work that goes into making a hood liner, why don't you just make a carbon fiber or fiberglass hood?

Yeah, maybe next time.