I’ve read a bunch on here about making fiberglass parts but still have a few questions;
Does it matter if I use Epoxy or Polyester resin for making the part itself? I understand Poly sets faster but other than that does it matter? Will be using matt, not cloth FWIW.

Also I’ve read that the fiberglass part may actually show through any lines or seams that are in the fiberglass matt layup itself several months down the road. Is there a way to prevent this? Last thing I want to do is make a hood scoop, cut/bond it into my hood, prime/paint/clear only to have it look like crap next spring.
I have a set of lower quarter scoops that I used poly resin and matt on the front and back to fill the previous owners GT holes, sanded out, then covered with a skim coat of Evercoat vett panel on the front, sanded, primed with the PPG, then Dupont high build.
Are those FG repairs going to show up/through next spring?
I swear this car will never ever be done.
Thanks in advance.

Doesn't matter what type of resin to make the part - just use polyester it's cheaper. Just make sure you mold in the part with SMC adhesive/filler. If you're making the part on the hood use epoxy resin to get a better bond to the SMC (have never done that so I don't know how well it holds, but it will hold better than polyester resin I'm sure).
You have to tear any edges in the middle of the part to avoid having print-through of cut edges.
I doubt the fiberglass & 'vette filler will hold up on the RRIM part. Best thing to do is pull molds off of the panels before painting them. The hi-build primer sanded with 1000 wet & waxed/mold released with the proper shtuff is a perfect surface to lay up molds (use gelcoat for both the mold & the part). Wait are these aftermarket fiberglass 1/4s? If so then if you ground everything with 24 grit ( "V"ing out the front of the holes) before fiberglassing then you should be fine. I might add that on polyester fiberglass parts 'vette panel filler is not necessary - bondo sticks just fine.
EDIT: You think your car is taking a long time? Think about this (470 hours so far, & a long way from finished): http://angelonearth.net/VW.html
~ Paul
aka "Tha Driver"

Custom Fiberglass Parts

[This message has been edited by Tha Driver (edited 09-29-2011).]

I have a solid female mold, am going to glass it and pull the part, then cut a same size hole in my hood, match up the surface level, temp attach in areas around the perimiter, grind the other areas down and then glass it in back to level to both attach and flush out the part to the stock hood. Remove temp attach points and do the same to those areas. I saw a write up on here before where somebody installed one like that and it came out really nice (sourmug? skitime?) will have to see if I can find it again. It’s more of a double vent than a scoop. Sort of like the one you make, but smaller…and different..

The rear quarters were aftermarket fiberglass, not the factory RRIM ones.

And I bought this one to drive while I finished up my GT. All it’s done is replace the GT as the project car and now the GT is collecting dust. I guess my wife was right once again, 1 project at a time!

A 90 VW Cabriolet? What, couldn’t find a Yugo to restore? just kidding, just kidding. That’ll be quite the sleeper with a small block in it.

Check out the threads where folks have installed my hood vent. Make sure to use bonding strips all the way around the vent. Grind everywhere you bond things with a 24 grit disc.
Use gelcoat in your mold (after waxing & the mold release) before laying up the 'glass. If you don't, you'll probably have hundreds of tiny pinholes in the resin. You have rollers to lay up the part, right?
Sleeper? Not likely with 3" flares & cowl hood & spoiler & ground F/X & wing & wild-as-hell paintjob. You saw the last photos, right?
~ Paul
aka "Tha Driver"

Custom Fiberglass Parts

I know a guy who has a Morris sedan. Its in really good shape except that it was in a flood right after it was bought new, up to its roof. The original owner kept it in a garage till my friend bought it 10 years ago to restore. He had a heart attack a few years back and its still setting partially apart in his garage. He might sell it if your interested.

Thanks Roger, but too far away. It'd have to be free in order for me to scrape up the money to get it here (my pickup is still apart too & I'd have to pay someone).
~ Paul
aka "Tha Driver"

Custom Fiberglass Parts

quote Originally posted by Tha Driver: Check out the threads where folks have installed my hood vent. Make sure to use bonding strips all the way around the vent.

Ya, I’ve read a couple of them and using strips of the hood as bonding strips on the underside is a great idea and much easier than what I was thinking. My only concern is that those strips would be visible and take away from the clean -stock look that I want. I’ll have to take a closer look at the underside vs my extractor, they might not even be visible after it’s all said and done. If that’s the case then I’ll definitely do it that way.
yup, i've got a roller.
Another FG question for ya, do I have to let the part sit after pulling it out of the mold or can I pull it and put it right into the hood? It seems that several install threads mention shrinking or pattern bleed through months later. Again, don’t want it to look like crap in the spring….assuming it gets color this year.

quote Originally posted by Tha Driver: Sleeper? Not likely with 3" flares & cowl hood & spoiler & ground F/X & wing & wild-as-hell paintjob. You saw the last photos, right? Custom Fiberglass Parts

No, i missed the last one that shows all that, I’m at work and it's probably not opening all the pictures properly. Sounds cool though. That is an excellent example of why i got into Fieros, they’re different and you don't see them every day. Being like everybody else is boring.

edit, OH that picture! Ya that's no sleeper. Pretty cool.

[This message has been edited by DLCLK87GT (edited 09-30-2011).]

quote Originally posted by DLCLK87GT: edit, OH that picture! Ya that's no sleeper. Pretty cool.

Let the part sit in the mold until it's fully cured. Then when you pull it out it won't warp & you can install it immediately. You won't get any print through if you use gelcoat & mat & tear the edges of the mat. Print through comes from hard edges of the mat & folks using woven cloth (the woven pattern can print through).
~ Paul
aka "Tha Driver"

Custom Fiberglass Parts

OK thanks once again Paul. Now like the PPG primer...a treasure hunt to find some gelcoat locally.