I've got some cracks in the roof skin from chassis flex from before a full frame X brace was welded to the floor. What's the best media to fill them? Evercoat fiberglass filler? Regular Bondo? believe it or not, I used 3M flexible bumper repair compound on a Camaro front fender...... It's held perfectly for 6+ years, think that would work here too?
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04:11 PM
PFF
System Bot
DimeMachine Member
Posts: 957 From: Eastern Metro, Minnesota, USA Registered: Sep 2011
3m flex parts repair material should hold and be least likely to redevelop cracks. If you are going for a show car finish, you may need to grind it out, add a layer of fiberglass matt and then duraglass/bondo - if you are going for the ultimate finish. Just my 2 Cents!
Don't use fiberglass. Don't use bondo. Don't use duraglass, unless they've changed the formula since I last used it (been awhile). Don't use 3m flex parts repair material unless it specifically says it will work on SMC fiberglass on the label. I use Evercoat 'Vette Panel Adhesive filler. Bottom line, don't use anything unless it specifically says it will work on SMC fiberglass on the label. http://gafieroclub.org/bbs/index.php?topic=469.0 EDIT: If you do a search with my username you'll find instructions on what to do. I've covered this several times. ~ Paul aka "Tha Driver"
He is right, do not use 3m flexible repair material on SMC. For repairing structural cracks you may want to grind down around the crack and repair it with Evercoat 865 SMC fiberglass resin with some fiberglass mat. If you have it handy, according to the Technical Data sheet for Duraglas, it can be used cosmetically over SMC. I just hope my roof never cracks!
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12:35 AM
fieroluke Member
Posts: 357 From: Erlangen, Germany Registered: Mar 2001
Well, flakes of about 0.5 x 1 inch come off, clearcoat, basecoat and whatever it is that is below that and above the fibreglass. In all, it is about 0.5mm thick flakes. Once they're off, you can see the grey fibres that the roof is made of. So I assumed it was gelcoat, but I'm really no fibreglass expert, so whatever GM used as finish before painting, that's what's flaking off now.
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10:59 AM
Gall757 Member
Posts: 10938 From: Holland, MI Registered: Jun 2010
Well, flakes of about 0.5 x 1 inch come off, clearcoat, basecoat and whatever it is that is below that and above the fibreglass. In all, it is about 0.5mm thick flakes. Once they're off, you can see the grey fibres that the roof is made of. So I assumed it was gelcoat, but I'm really no fibreglass expert, so whatever GM used as finish before painting, that's what's flaking off now.
Yeah; no gelcoat. If you see fibers grind out the damage with a 24 grit disc & use 'Vette Panel Adhesive/filler. ~ Paul aka "Tha Driver"
Well, flakes of about 0.5 x 1 inch come off, clearcoat, basecoat and whatever it is that is below that and above the fibreglass. In all, it is about 0.5mm thick flakes. Once they're off, you can see the grey fibres that the roof is made of. So I assumed it was gelcoat, but I'm really no fibreglass expert, so whatever GM used as finish before painting, that's what's flaking off now.
Yup, I have the same problem on my '88 GT. The more I drive it, the more it seems to chip.... And I can now see fibers mostly around the sunroof weather strip.
------------------ =-Eric the Dread
1988 Fiero GT 2.8L V6 2001 Grand Prix GTP SC3.8L V6
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04:27 PM
Sep 25th, 2011
fieroluke Member
Posts: 357 From: Erlangen, Germany Registered: Mar 2001
Wonderful. If the car was still under warranty, we could complain ;-)
Sooo, would it be better to find a good roof section and swap or fix my flaking section? In other words: is this going to happen to all roof panels sooner or later, or was my roof painted on a Monday?
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07:26 AM
PFF
System Bot
Gall757 Member
Posts: 10938 From: Holland, MI Registered: Jun 2010
SMC will absorb moisture and expand slightly. I am thinking the sunroof hole has a raw edge or there are some cracks that go through the primer. Does your car see a lot of water?
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10:44 AM
fieroluke Member
Posts: 357 From: Erlangen, Germany Registered: Mar 2001
Ok, to resurrect an old thread: where would I get this "Evercoat 'Vette Panel Adhesive filler"? Is that something common that I can find at say Pep Boys or Autozone, or does it have to be ordered?
Reason I'm asking: I'll be in the US soon for a few days, but won't have much time hunting for parts, so I'd like to know where to look.
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08:58 AM
seajai Member
Posts: 1541 From: Linwood Township, Minnesota Registered: Feb 2012
I looked on Evercoat's website, the "Vette panel adhesive/filler" says on the can that it is not for SMC fiberglass. But the product description says it can be used as a filler but not to bond. So what product should be used to bond the panels?
Vette Panel Adhesive/Filler™ A polyester body filler for fiberglass and SMC panels. No shrinkage. Helps prevent repair mapping on seam lines over fiberglass repairs. Used to bond fiberglass panels only, not SMC. Blue cream hardener included.
Ok, to resurrect an old thread: where would I get this "Evercoat 'Vette Panel Adhesive filler"? Is that something common that I can find at say Pep Boys or Autozone, or does it have to be ordered?
Reason I'm asking: I'll be in the US soon for a few days, but won't have much time hunting for parts, so I'd like to know where to look.
Most local autobody supply/paint supply places have it. Yeah make sure you get the one made for SMC. ~ Paul aka "Tha Driver"
How does that happen? Unless the UV rays are insane, or people walked on your roof, or the car was never waxed?
I have seen this on some Michigan cars. A week or two of drizzle and overnight freeze-thaw cycles.....sort of like how we get pot holes in the street. Some years it can go on for over a month. It's true that a little preventative maintenance can take care of it, but very often the PO was not into cars that much.....
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10:51 AM
DLCLK87GT Member
Posts: 2694 From: South Jersey, USA Registered: Feb 2009
I had the same issue on my Formula and Paul/ThaDriver is 100% correct, grind out the rough spots with a very coarse disk/paper, I used a 24 I think. I also dug around with a small blade and found a few other areas that were starting to flake off that looked ok but with a little poking, popped up. Look for hairline cracks or discolorations and make sure it’s not starting to lift. Get all that crap off now or you’ll be doing it again in a few months. Mine looked pretty bad when I was done digging and grinding out all the loose flaking crap. (at work or I’d post a few pixs). Then use the Evercoat vet panel stuff just like you would regular Bondo (but never use regular bondo on a Fiero) and fill them in and sand smooth. My car is still in primer but looks great. I couldn't find it locally and got it off Amazon.com for thirty something. I wouldn’t advise a roof panel swap, removing a good one without damaging it at the upper windshield corners isn’t easy. Chances are it'll crack and you'll need to do the same thing to fix it anyway. Fixing what you’ve got would be easier. Also be aware that Evercoat is tough stuff and doesn’t sand as easily as Bondo does so don’t glob it on or your arm and shoulder will be sore as hell by the time you’re done sanding it all down.
Edit to add, if you’re serious about fixing this once and for all you may want to pull the sunroof gasket to get any issues on the corners and inside edges. If you don’t those areas could over time spread back up to the top. Be careful pulling the gasket, mine was glued down to the tracks and tore but I already had a new one so it was no big deal.
[This message has been edited by DLCLK87GT (edited 04-27-2012).]
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11:19 AM
GodSend Member
Posts: 861 From: Hamilton, Ontario, Canada Registered: Aug 2000
I have seen this on some Michigan cars. A week or two of drizzle and overnight freeze-thaw cycles.....sort of like how we get pot holes in the street. Some years it can go on for over a month. It's true that a little preventative maintenance can take care of it, but very often the PO was not into cars that much.....
X2, my car has this BAD, it's almost always stored outside. Michigan is hell on cars.
