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Cracks in the roof skin by Joe 1320
Started on: 09-22-2011 04:11 PM
Replies: 25 (555 views)
Last post by: RWDPLZ on 04-27-2012 02:35 PM
Joe 1320
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09-22-2011 04:11 PM Click Here to See the Profile for Joe 1320Click Here to visit Joe 1320's HomePageClick Here to Email Joe 1320Send a Private Message to Joe 1320Edit/Delete MessageReply w/QuoteDirect Link to This Post

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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DimeMachine
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09-22-2011 04:23 PM Click Here to See the Profile for DimeMachineSend a Private Message to DimeMachineEdit/Delete MessageReply w/QuoteDirect Link to This Post

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!

------------------
87 NB, 3800SC 13.10 at 102.5 quarter mile, custom dash

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Tha Driver
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09-22-2011 11:24 PM Click Here to See the Profile for Tha DriverClick Here to visit Tha Driver's HomePageSend a Private Message to Tha DriverEdit/Delete MessageReply w/QuoteDirect Link to This Post

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"

Custom Fiberglass Parts

[This message has been edited by Tha Driver (edited 09-22-2011).]

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DimeMachine
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09-23-2011 12:35 AM Click Here to See the Profile for DimeMachineSend a Private Message to DimeMachineEdit/Delete MessageReply w/QuoteDirect Link to This Post

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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fieroluke
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09-23-2011 10:48 AM Click Here to See the Profile for fierolukeClick Here to visit fieroluke's HomePageClick Here to Email fierolukeSend a Private Message to fierolukeEdit/Delete MessageReply w/QuoteDirect Link to This Post

I don't have cracks, but the gelcoat is coming off especially around the sunroof edges, but also starting on the a-pillars and hood.

What do you suggest? Same material for repairs? Is this common?

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Gall757
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09-23-2011 10:52 AM Click Here to See the Profile for Gall757Click Here to Email Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post

gelcoat? Do you mean Clearcoat?? There is no gelcoat on a Fiero....

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fieroluke
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09-23-2011 10:59 AM Click Here to See the Profile for fierolukeClick Here to visit fieroluke's HomePageClick Here to Email fierolukeSend a Private Message to fierolukeEdit/Delete MessageReply w/QuoteDirect Link to This Post

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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Gall757
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09-23-2011 11:14 AM Click Here to See the Profile for Gall757Click Here to Email Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post

oohh,, The primer is failing.

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Tha Driver
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09-23-2011 04:16 PM Click Here to See the Profile for Tha DriverClick Here to visit Tha Driver's HomePageSend a Private Message to Tha DriverEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by fieroluke:

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"

Custom Fiberglass Parts

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88 Dread GT
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09-23-2011 04:27 PM Click Here to See the Profile for 88 Dread GTSend a Private Message to 88 Dread GTEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by fieroluke:

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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fieroluke
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09-25-2011 07:26 AM Click Here to See the Profile for fierolukeClick Here to visit fieroluke's HomePageClick Here to Email fierolukeSend a Private Message to fierolukeEdit/Delete MessageReply w/QuoteDirect Link to This Post

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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Gall757
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09-25-2011 10:44 AM Click Here to See the Profile for Gall757Click Here to Email Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post

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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fieroluke
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09-25-2011 03:31 PM Click Here to See the Profile for fierolukeClick Here to visit fieroluke's HomePageClick Here to Email fierolukeSend a Private Message to fierolukeEdit/Delete MessageReply w/QuoteDirect Link to This Post

It's in Germany, so, yes - it does see lots of water... ;-)

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fieroluke
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04-21-2012 08:58 AM Click Here to See the Profile for fierolukeClick Here to visit fieroluke's HomePageClick Here to Email fierolukeSend a Private Message to fierolukeEdit/Delete MessageReply w/QuoteDirect Link to This Post

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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seajai
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04-21-2012 09:31 AM Click Here to See the Profile for seajaiClick Here to Email seajaiSend a Private Message to seajaiEdit/Delete MessageReply w/QuoteDirect Link to This Post

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.

CATALOG NO. SIZE UNITS/CASE WT./CASE
870 Quart 6 24 lbs.
880 Gallon 4 53 lbs.

Here is the page on their website

[This message has been edited by seajai (edited 04-21-2012).]

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JimmyS
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04-21-2012 12:27 PM Click Here to See the Profile for JimmySClick Here to visit JimmyS's HomePageClick Here to Email JimmySSend a Private Message to JimmySEdit/Delete MessageReply w/QuoteDirect Link to This Post

This is what you want to use.

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Tha Driver
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04-21-2012 02:02 PM Click Here to See the Profile for Tha DriverClick Here to visit Tha Driver's HomePageSend a Private Message to Tha DriverEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by fieroluke:

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"

Custom Fiberglass Parts

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seajai
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04-21-2012 02:09 PM Click Here to See the Profile for seajaiClick Here to Email seajaiSend a Private Message to seajaiEdit/Delete MessageReply w/QuoteDirect Link to This Post

Hmm, weird, I can't find that on their website. Catalog# 870 comes up as "non-smc"

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josef644
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04-21-2012 04:51 PM Click Here to See the Profile for josef644Click Here to Email josef644Send a Private Message to josef644Edit/Delete MessageReply w/QuoteDirect Link to This Post

It runs around $39.00 a quart. I got mine at www.AutoBodyToolmart.com

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fieroluke
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04-27-2012 07:08 AM Click Here to See the Profile for fierolukeClick Here to visit fieroluke's HomePageClick Here to Email fierolukeSend a Private Message to fierolukeEdit/Delete MessageReply w/QuoteDirect Link to This Post

Thanks for the info everyone!

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2.5
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04-27-2012 09:34 AM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post

How does that happen? Unless the UV rays are insane, or people walked on your roof, or the car was never waxed?

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Gall757
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04-27-2012 10:51 AM Click Here to See the Profile for Gall757Click Here to Email Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by 2.5:

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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DLCLK87GT
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04-27-2012 11:19 AM Click Here to See the Profile for DLCLK87GTSend a Private Message to DLCLK87GTEdit/Delete MessageReply w/QuoteDirect Link to This Post

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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GodSend
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04-27-2012 01:35 PM Click Here to See the Profile for GodSendClick Here to Email GodSendSend a Private Message to GodSendEdit/Delete MessageReply w/QuoteDirect Link to This Post

Just a quick question. Same SMC Vette filler for all panels? Roof, front/rear bumper/side quarter panels? I have a few repairs needed on all those..

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Tha Driver
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04-27-2012 02:07 PM Click Here to See the Profile for Tha DriverClick Here to visit Tha Driver's HomePageSend a Private Message to Tha DriverEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by GodSend:

Just a quick question. Same SMC Vette filler for all panels? Roof, front/rear bumper/side quarter panels? I have a few repairs needed on all those..


Definitely not. It's only for SMC: the roofs & hood/decklid.
http://gafieroclub.org/bbs/index.php?topic=469.0
~ Paul
aka "Tha Driver"

Custom Fiberglass Parts

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RWDPLZ
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04-27-2012 02:35 PM Click Here to See the Profile for RWDPLZClick Here to visit RWDPLZ's HomePageSend a Private Message to RWDPLZEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by Gall757:


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.

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