How to fix a warped fiberglass panel

S

strum456

Oldtimer
I got a glass tail pan from Outlaw Rods for my 34 chevy since the steel one was beyond repair. I made the mistake of bolting it on a year ago with some pressure on it right in the center where the old spare tire mount used to bolt on. Long story short, now my panel has a wave in it, probably due to the stress that was on it for the last year.

I tried sanding down some of the gelcoat on the high spot and using filler on both sides to blend it, with little success. It looks like I might to have to go through the gelcoat to get this out. If I have to go that far sanding the top side, I was planning to reinforce the underside with fiberglass matte.

What will I be getting into if I have to go through the gelcoat? Can I put epoxy on bare glass? What type of resin should I use for the matte? Is there a better way to repair this, like bend it back to normal somehow?
 
So you've taken the mount out that was causing the trouble?

Sometimes the best way to fix a damaged fiberglass part is to just remove the bad section, properly prepare the edges using really wide tapers or bevels, and lay up some new mat and resin over a temporary form that you place on the back of the panel. A temporary form can be as simple as a piece of chipboard (like off the back of a notepad) covered with duct tape and taped or hot glued to the back of the panel, which can be removed after the 'glass kicks.
 
any repair will telegraph . a patch will show, reinforcing from underneath will show , best bet would be to just use filler on top. evercoat has a new hybrid epoxy filler or you can use vette panel bond adhesive/filler .
 
That mount was definitely pushing on it, but not that hard. The wave is off to the side about 8" from the mount though. Will a little pressure do this? Anyway, the mount is not touching the tail pan anymore.

I don't think I will have to sand much more to get this out, but I am afraid to go through the gelcoat. I know next to nothing about this stuff, but I don't think it is SMC.

What are you saying Shine, leave the high spot there and build up around it? Its a 1/16th or less.
 
just block and epoxy . skim it and go .

put it in the sun and it may return if it had stress on it .
 
Crash and Shine,

I respect and value both of your opinions greatly. How bad would the wave have to be to justify cutting it out? I gave it several days of sun after I took it off the car, but before I did any work to it (I think this helped). Then I tried sanding off a little gelcoat anid building up beside it. It has seen 4 more days of sun since that (I have seen no change). Right now, I can feel the wave with my hand, but I really have to be paying attention to notice it. With my skill level, I doubt I could get it this close if I cut it out and put new in. What is the reason for cutting it out...to get the stress off of it?
 
you can not cut out and patch fiberglass on a flat surface it will telegraph the repair because of the difference in thickness of the glass. this is why most cheap repairs done on covettes show in the sun. also why we have to redo the seams. get some evercoat vette panel adhesive/filler and use it to feather out the wave. it is the only product i know of that works.
dont even consider any durglass crap .
 
shine;9140 said:
you can not cut out and patch fiberglass on a flat surface it will telegraph the repair because of the difference in thickness of the glass. this is why most cheap repairs done on covettes show in the sun. also why we have to redo the seams. get some evercoat vette panel adhesive/filler and use it to feather out the wave. it is the only product i know of that works.
dont even consider any durglass crap .
Click to expand...


Hoping this isn't a highjack... It is about fiberglass
Shine I will eventually be looking at some R front fender repair on a 63 Avanti and this thread has me wondering what the best approach will be. Can you suggest some best practice procedures? Some do's and don'ts and any other wisdom you might be willing to impart? Pleeeeeeze?
 
Well Crash I'm all ears. That's why I'm here.
I use these forums as lectures and then practice in the 'lab' using a 58 GMC 1/2 ton to develop some skills and techniques on. All in hopes of not screwing up to bad on the Avanti when the time comes.

And I would also like to say this site has hands down the best quality info and suggestions and feedback of any I've visited so my thanks to all who post here. I may not find the answer to every question I have here.... but I always look here first.
 
with glass it is always better to do panel replacement if possible. the ins co's started that piece crap in the 60's. never seen one you couldn't see where it was cut.
when it comes to glass i know a little but never , ever listen to me on collision work............. :)

yes it is a great site. the guys here know what they are doing . those posers from the other sites wont dare come here spewing their google knowledge.
 
On those older cars like that, the best use of the fiberglass panels that you can buy is to use them for a pattern for making a new metal one. Even at that, you need to make sure that the part fits when you get it, since often they are already out of shape. I have not seen a fiberglass replacement part that has not deformed over time.

Aaron
 
I want to say that repairs are possible on fiberglass, though as shine says, many times the repair area can be picked out over time. But remember that the cars shine does are show quality and he is obviously very picky about their appearance. I have done many fiberglass repairs where the only one who could see anything wrong was me. Done properly, the ghosting will be almost non-existent. I'd even go as far as to say I have occasionally achieved totally invisible repairs by using very careful technique, but I am not wanting to cross shine on this subject.

It's probably unlikely that a novice could achieve a totally invisible fiberglass patch job.
 
it's time that gets you crash. after a while the reaction to uv really screws them up. look at just about any older vette and you can see every seam . the panel bond seems to be holding so far.
 
this is why they do press molded parts. uniformity in thickness. that is why repairs show. different thickness reacts different to heat and uv. remember fiberglass is just cured resins but not completely. i have seen old vette bodies you could poke holes in with your finger.
 
There is no doubt that Shine could answer that question better than me. I just know that they don't. A couple of years ago I had a guy contact me from Florida about making him a pair of steel rear fenders for his Model T street rod. He shipped me a 'glass fender to use as a sample. I wrongly understood that the fender had just been removed from the vehicle, so I made the metal one an EXACT DUPLICATE, and shipped it to him. The customer called me and told me that the fender was about 1 1/2" too wide at the bottom. He then advised me that the 'glass fender had been removed from the vehicle about 5 years ago. I now have an extremely large paper weight!

Aaron
 
Would you use the Vette Panel Adhesive/filler on a new kit car, say, one from Factory Five? I have a customer that wants me to finish the body & paint on his Factory Five hot rod and was wondering what the best filler to use would be. Of course, the panels don't line up for squat and will take a lot of sanding, filling, and adjusting to get right.

I also have some of the West Systems epoxy, and some of their fairing filler that I bought for a previous job that didn't pan out.
 
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