Fiberglass hood repair/correction question

-
Righty Tighty

Righty Tighty

Blame it on the dog
FABO Gold Member
Joined
Aug 16, 2019
Messages
3,198
Reaction score
3,920
Location
Sahuarita, AZ
Hey FABO,

You all may remember the thread I had going about my Stinger Fiberglass hood that arrived damaged. I'm finally getting around to deciding on options for correcting the damage, and mostly what I have questions about is how to go about correcting the incorrect contour of one corner at the cowl end.

The damage to the hood was basically in two areas: chipped corners and the incorrect contour previously mentioned. I feel pretty confident I can fix the chipped corners on my own, and THINK I have a decent plan on how to correct the contour. I wanted to post here just in case someone has some advice and/or if anyone runs across a similar scenario and needs help -- they can use this thread.

Here's the incorrect contour:
94087F2A-1374-4765-AD5A-BE0403D1C0A0.jpeg


AD07421D-2136-4A43-B852-B61E51E822C0.jpeg


It's not off by much, but enough to where it obviously doesn't match the fender line. I've read that you can heat fiberglass and reshape it. My plan was to use a heat gun and slowly heat it until it becomes pliable, then mold it to the correct contour. That section is a little thinner than the rest of the hood, so I was going to add fiberglass resin to bring it to the same thickness.

To fix the chipped corners, my plan is to remove the gel coat, apply some small pieces of fiberglass fabric and finish with polyester resin. The damage on the corners is about 1/4” x 1/4”.
9E7A085C-941C-4503-A69F-48CAE76B4118.jpeg



There are some small imperfections that will need addressing (a couple dings and very shallow scuffs), I plan to fill those with body filler.

I watched videos that offered two different philosophies regarding gel coat after a repair: one said you don't need to add gel coat, another said you should. Should I add gel coat after the repair or not?

So, all in all, how does all of this sound? Any advice?
 
I had the same issue on a Challenger hood and what I did was ground the underside down thin. I then took a piece of 2"x 1/8" aluminum flat stock and bent it to the contour of the fender.

Drill through the hood and flatstock in a couple of locations and install rivets through the hood into the flat stock with JB weld between the two.

Make sure the contour is correct by installing the hood. Grind the rivets off protruding through the flat stock and put desired amount of fiberglass cloth and resin over the aluminum stock. Then grind off the rivets on the outside of the hood and cover them with resin.

Heating the hood will not work. That only works on ABS inner parts. My race hood and parts from glass tech have aluminum molded in them to make them ridged . Good fiberglass parts all have aluminum molded into them at those areas. You can also put a strip across the back to make it straight from looking over it in the car
 
Thanks. That's a good idea with the aluminum stock. Any tips for the chipped corners?
 
Always use resin and cloth when dion repairs. Find the stiff cloth and shred the hair off of it . Mix it with the resin. for fiberglass repairs
Do not use gorilla hair or fiber strand filler that comes in a can. That is used for a sealer on metal repairs to prevent moisture. entering the repair from behind causing bubbling and cracks.
 
Cool, thanks for the tips. Originally I was going to take it to a shop, but I’d like to at least give it a shot. This definitely seems like a doable job, just need to take my time.

Is there anything I can do to help prevent the corner from cracking when I rivet the aluminum to it? Or do you think it’s flexible enough already?
 
Righty Tighty said:
Cool, thanks for the tips. Originally I was going to take it to a shop, but I’d like to at least give it a shot. This definitely seems like a doable job, just need to take my time.

Is there anything I can do to help prevent the corner from cracking when I rivet the aluminum to it? Or do you think it’s flexible enough already?
Click to expand...
grind some material off the inside and rebuild
 
Just spitballin cause I know nothing about working with fiberglass, but I wonder if you could take a heat gun and gently heat that corner and ease it down and even it up with the corner of that fender? Just a thought like a fart in a windstorm.
 
RustyRatRod said:
Just spitballin cause I know nothing about working with fiberglass, but I wonder if you could take a heat gun and gently heat that corner and ease it down and even it up with the corner of that fender? Just a thought like a fart in a windstorm.
Click to expand...
I wondered the same thing, but we've covered that already. Oldmanmopar said it would only work on ABS inner parts. Then again, now that we're revisiting the heating idea, I'm not convinced they added any aluminum at that corner. My experience with this hood (and the company that made it) hasn't been stellar, so nothing would surprise me at this point.
 
Righty Tighty said:
I wondered the same thing, but we've covered that already. Oldmanmopar said it would only work on ABS inner parts. Then again, now that we're revisiting the heating idea, I'm not convinced they added any aluminum at that corner. My experience with this hood (and the company that made it) hasn't been stellar, so nothing would surprise me at this point.
Click to expand...
Well, maybe find a piece of scrap fiberglass and heat it and see what happens.
 
Fiberglass tends to have a memory, the next time it gets hot, or up to temperature, it will probably return to where it was originally. Forget about the gel coat, in the end, gel coat is your enemy. It has no strength, it's just there to fill, so that the Fiberglass will lay without gaps. They usually use polyester ( cheap resin) for their lay ups. Unfortunately, I know enough about fiberglass to be dangerous. There are more ways than one to accomplish your issues, and, they may or may not work. I don't believe that I can explain here how to do it, maybe someone else can. Sorry.
 
CRUZE 418 said:
Fiberglass tends to have a memory, the next time it gets hot, or up to temperature, it will probably return to where it was originally. Forget about the gel coat, in the end, gel coat is your enemy. It has no strength, it's just there to fill, so that the Fiberglass will lay without gaps. They usually use polyester ( cheap resin) for their lay ups. Unfortunately, I know enough about fiberglass to be dangerous. There are more ways than one to accomplish your issues, and, they may or may not work. I don't believe that I can explain here how to do it, maybe someone else can. Sorry.
Click to expand...
Agreed. I am about the same. Have done enough fiberglass repairs to be dangerous. And yes, forget about the gelcoat. It does nothing. There are various ways to fix that and all of them would probably work. You might not want to do it this way but this is how I would do it.
Take yourself a piece of sheet metal or aluminum a little bigger than the area you are repairing, say by about 4 or 5 inches. Shape it to the right contour of the fender edge. Flip your hood upside down and grind the fiberglass at the hood corner thin enough that it's pliable but not completely through. Flip the hood over, pop rivet your sheet metal to the hood so the corner takes on the correct contour. You want the overlapping amount of sheet metal to hold it in the right shape. Flip the hood back over and glass the corner, overlapping each layer slightly. You can use polyester resin or epoxy. In this case it doesn't matter. Layer it to your satisfaction. Let it cure well.
Once it's cured, flip the hood over, grind off the pop rivets, remove the sheet metal, sand the upper surface or grind it lightly, fill the imperfections and prime. Finish the underside the same way.
As I said, there are other ways, but that will work if it's done right. Just my 2 cents worth.
 
kdbunn said:
Agreed. I am about the same. Have done enough fiberglass repairs to be dangerous. And yes, forget about the gelcoat. It does nothing. There are various ways to fix that and all of them would probably work. You might not want to do it this way but this is how I would do it.
Take yourself a piece of sheet metal or aluminum a little bigger than the area you are repairing, say by about 4 or 5 inches. Shape it to the right contour of the fender edge. Flip your hood upside down and grind the fiberglass at the hood corner thin enough that it's pliable but not completely through. Flip the hood over, pop rivet your sheet metal to the hood so the corner takes on the correct contour. You want the overlapping amount of sheet metal to hold it in the right shape. Flip the hood back over and glass the corner, overlapping each layer slightly. You can use polyester resin or epoxy. In this case it doesn't matter. Layer it to your satisfaction. Let it cure well.
Once it's cured, flip the hood over, grind off the pop rivets, remove the sheet metal, sand the upper surface or grind it lightly, fill the imperfections and prime. Finish the underside the same way.
As I said, there are other ways, but that will work if it's done right. Just my 2 cents worth.
Click to expand...
Post #2
 
That corner isn't much, you could probably use duct tape to form your corner. When you grind it back, feather it, your probably going to get a fiberglass kit from the auto store. Get some 1 1/2" throw away brushes and plastic cocktail glasses and I use tongue depressors for mixing, grind the mixing edge square. Trouble is, the quantity you have to buy these. Make sure that you mix your resin well, this is a learning curve, how much catalyst you use depends on the temp, and it can get so hot that it will burn, watch where you put your mixing cup when done. When it starts to get off, your done, you may have to wait and start over, that's the learning curve. Wet the lay up area with resin. No more than 2 layers for side one, go out to the end of the feathered edge, make sure that your glass gets wet, but not soaked. Here's a trick, if you have your bondo. When the resin is curing, still tacky, but set. Smear a coat of bondo over your lay up, then you don't have to destroy the top layer of fiberglass for your first coat of bondo with sanding. After it cures, 24 hrs. remove whatever you have chosen for a mold. Grind that back similar to what you did yesterday. Wet that area with resin and probably one layer of glass. There is a trick to all of this, you are trying to bond this corner back onto the fender so that it it stays. Repeat, do the same thing you did yesterday. 24hrs. Sand or grind to finish, see how you did. You may or may not have to repeat parts of the process to achieve your goal.
There are other resins, cloth weights, cloth weaves , cloth for polyester, cloth for epoxy resins, fillers like flox and microballons . It can make your head spin. This is why I was hesitant to jump in here.
Oh, and fiberglass likes to be warm when curing. Not Hot, but warm, and it cures more over time , well past the 24 hr mark.

That curve at the back of the hood, is it warped that bad? Hinge adjust? Otherwise, that could get interesting for a beginner, even I would do some research with someone who knows more than me. Like a place that specializes in Corvettes.
 
I have used heat on a fiberglass trunk lid I bought for my '65 Barracuda. No aluminum in that thing. The back section was literally 1" out from flush on the driver's side. I used a propane torch/plywood clamped on the section (with care) to move it. It did move. I roughed up the inside, added fiberglass cloth/resin and it took a permanent set. Good to go to this day.
 
The difference between success and junk is a few seconds. Sometimes we get lucky, I have had both success and junk doing that!
 
CRUZE 418 said:
That curve at the back of the hood, is it warped that bad? Hinge adjust? Otherwise, that could get interesting for a beginner, even I would do some research with someone who knows more than me. Like a place that specializes in Corvettes.
Click to expand...
The picture in the first post is with the hood adjusted as well as it can be. The curve isn't the worst in the world, but I know I'll see it every time I look at it. With all the advice given, I may just take it to a shop and see what they'd charge to fix it.
 
CRUZE 418 said:
The difference between success and junk is a few seconds. Sometimes we get lucky, I have had both success and junk doing that!
Click to expand...
I agree. I could tell I was close to screwing up but controlled the heat to get it there and no more. Just my experience. I did consider myself lucky on that one. It can work though.
 
So maybe heat isn’t the way to go for someone like me who’s never done it before.

I feel like I could pull off the aluminum plate idea. The curve isn’t so bad that it would take a lot to correct it, so I’m still considering doing it myself.
 
You must log in or register to reply here.
-

Back
Top