People with fiberglass panel experience please comment...

[dave.g.in.gansevoort]

I'm finishing up on the fabrication of the nose support hoop. And I was working on it this afternoon and have a few concerns.

I bought the nose about 2 years ago. It's been sitting in various positions in the garage, sometimes on the Whatever project, sometimes on the floor, sometimes at weird angles in a corner out of harms way. About the time I bought it, I made a pattern of the shape of the back of the nose, and being careful to ensure that the shape of the nose side to side was essentially the same. I then made the first support hoop, cutting a sheet of 1/16 cr steel sheet and forming an angle support that matched both the nose and the steel sheet.

When I shaped the next iteration of the support hoop, I made sure that it matched the curvature. Today getting it ready to affix the nose to the support hoop, I had gaps between the two here and there. And I don't think I'll be able to make them mate up perfectly. This leads to my question:

If left unsupported in bad positions, do fiberglass parts warp, for lack of the proper term? I'm worried that the resulting gaps here and there will be a problem when I try to bond them together. I have some alternative ways to make the assembly work, so this is for my edification.

Thanks for any information.

[Loren]

I've had two cars with fiberglass hoods, my first '70 El Camino and the Challenger, each hood purchased used. I'm pretty sure those could not have come out of the mold in as horrifically warped a condition as they were when I got them and started trying to make them work so yeah the stuff must warp.

By the time you build up a fiberglass panel to where it holds its shape as well as steel, it weighs as much as steel...at least.

[dave.g.in.gansevoort]

I've had two cars with fiberglass hoods, my first '70 El Camino and the Challenger, each hood purchased used. I'm pretty sure those could not have come out of the mold in as horrifically warped a condition as they were when I got them and started trying to make them work so yeah the stuff must warp.

By the time you build up a fiberglass panel to where it holds its shape as well as steel, it weighs as much as steel...at least.

I guess I'll have to put up with the warping. Did your panels hold shape after you got them to fit?

[Loren]

On the Chall I picked the worst area and cut a 1x2 piece of wood to fit as a cross member and 'glassed it in, then cut the scoop off and re-attached it more straight, then built up the flimsiest areas with mat and resin and finally bondo, and with all that it's held pretty straight. I counted nearly 40 hours of novice work into that hood, with experience I think 8-10 would have done it.

The El Camino hood which even w/ an L88 middle was to replace a cowl hood that flew up and bent, the 'glass one probably could have been improved with a wood cross member or two also. As soon as you give the stuff some shape or reinforcement it helps a lot.

[SuperBuickGuy]

the thinner the fiberglass, the more susceptible it is warping. Also, fiberglass does move with changes in temperature...

[DanStokes]

I've only done a little fiberglass work but from my limited experience it will "take a set" depending on the support behind it. If you're sure your support hoop is the right shape I'd say pull (clamps, screws, whatever works) the nose to the support and bond it into the shape you want. From the pics that nose doesn't seem to have much if any built-in support.

[dave.g.in.gansevoort]

I've only done a little fiberglass work but from my limited experience it will "take a set" depending on the support behind it. If you're sure your support hoop is the right shape I'd say pull (clamps, screws, whatever works) the nose to the support and bond it into the shape you want. From the pics that nose doesn't seem to have much if any built-in support.

No built in support at all. It's intended for a roundy pounder type race car, and weight is important in that realm. I'd say it's half the thickness of the body. By the looks of it, it's made with a chopper gun, no mat or weave showing in it.

So what a denizen on that other car site showed me, was instead of permanent bonding of the nose to the support structure that he built, he put the fuzzy side of Velcro between the two parts. Cushioning and takes up the slightly wavy gaps. He also used it on the hood side to cushion flathead screws thru the flange and nose, burying the screws in the Velcro. I'm going to give that a try, and save a bunch of $$$$$$$ as well, not having to buy the gun for the bonding agent.

I'll be working on that as soon as the current migraine lets up. Like Rosanne Rosannadana always said, "If it's not one thing, it's another..."

[DanStokes]

No built in support at all. It's intended for a roundy pounder type race car, and weight is important in that realm. I'd say it's half the thickness of the body. By the looks of it, it's made with a chopper gun, no mat or weave showing in it.

So what a denizen on that other car site showed me, was instead of permanent bonding of the nose to the support structure that he built, he put the fuzzy side of Velcro between the two parts. Cushioning and takes up the slightly wavy gaps. He also used it on the hood side to cushion flathead screws thru the flange and nose, burying the screws in the Velcro. I'm going to give that a try, and save a bunch of $$$$$$$ as well, not having to buy the gun for the bonding agent.

I'll be working on that as soon as the current migraine lets up. Like Rosanne Rosannadana always said, "If it's not one thing, it's another..."

That could work though I have zero experience.

[SuperBuickGuy]

I've only done a little fiberglass work but from my limited experience it will "take a set" depending on the support behind it. If you're sure your support hoop is the right shape I'd say pull (clamps, screws, whatever works) the nose to the support and bond it into the shape you want. From the pics that nose doesn't seem to have much if any built-in support.

a helpful thing to remember - glass never stops flowing. Look at old windows, that waviness at the bottom? that's the glass as it sags. It takes time to flow, but even cold glass is not a solid.

[dave.g.in.gansevoort]

a helpful thing to remember - glass never stops flowing. Look at old windows, that waviness at the bottom? that's the glass as it sags. It takes time to flow, but even cold glass is not a solid.

Never thought about that. I did some experimental work with glass at Battelle way back when, so I suppose between the glass fibers and the resin used, it's become clear to me that in fact the composite flows and creeps. It took SBGs reminder to put the 2 together. Hey, I'm getting old, not as old as Dan. But then again who is?

Thanks for getting the little gray cells working...

[anotheridiot]

can you add layers of gel coat to it once you get the shape right? it is hafl the thickness.

[dave.g.in.gansevoort]

can you add layers of gel coat to it once you get the shape right? it is hafl the thickness.

I don't know. This is the first time I've messed with fiberglass of any sort. Well, there was that time late 60s, a snowmobile, a tree, and a teenager (me). The hood came out of it slightly better than the teenager (me). And the teenager tried to fix the broken bodywork himself. It was a gooey mess, that never set up. And it cost twice as much as the original estimate to get it repaired correctly. But I'm much better now...

So 55 years on, and I still have nightmares about trying to work with fiberglass. I'm going to try to pull it back in shape, sloooowwwwwllllllyyyyy, with screws thru the flange and support hoop. And big fender washers! That's hopefully today's effort. We'll see...

[SuperBuickGuy]

I don't know. This is the first time I've messed with fiberglass of any sort. Well, there was that time late 60s, a snowmobile, a tree, and a teenager (me). The hood came out of it slightly better than the teenager (me). And the teenager tried to fix the broken bodywork himself. It was a gooey mess, that never set up. And it cost twice as much as the original estimate to get it repaired correctly. But I'm much better now...

So 55 years on, and I still have nightmares about trying to work with fiberglass. I'm going to try to pull it back in shape, sloooowwwwwllllllyyyyy, with screws thru the flange and support hoop. And big fender washers! That's hopefully today's effort. We'll see...

it is amazingly difficult to make fiberglass put on the outside of the gel coat to look good. If you're going to add structure, do it underneath - your goal is at least 1/4" of depth with 3/8" being optimal

[dave.g.in.gansevoort]

it is amazingly difficult to make fiberglass put on the outside of the gel coat to look good. If you're going to add structure, do it underneath - your goal is at least 1/4" of depth with 3/8" being optimal

Yeah anything I do, I want my butchery on the underside.

You can see the step on the back edge of the nose. The steel support structure is fitted to the inside of the nose at that point. Whatever ends up as my feeble attempt at a brilliant solution has to leave room for the hood and side panels to end up nestled in the step flush with the top of the step. Same with the body. That however is so well supported by the double firewall/engine plate/inner support hoop, that there's nothing I can do to screw it up.

So now I'm off to the garage to see if I can have an epiphany. I'm counting on it, but not expecting one...

ps: I'm planning on using 0.060 3003 half hard aluminium for the hood and side panels.

[fatguyzinc]

bolt/clamp/screw nose in as close a shape as you can get onto your hoop, then let it sit out side in sun for a week.
or heat with a heat gun/hairdryer/ it will 'relax' into that shape. then when it cools down, loosen and then
retighten/shim/washers/etc to get it even closer to needed shape. repeat heat/cool cycle. retighten again....
see where im going with this?

you will be surprised how much better you can get the fit this way. just takes some time/work.

p.s. corvettes.... nuff said.