[Steve Barcak]

Here is a fairly unique problem of torn sheet metal, at least I think it is.

Am not quite sure how to tackle this problem.

Has anyone made repairs for situations like this?

You are looking at a 72 GTO fender. The metal is torn above the air extractor behind the tire.

What would be the best way to make this repair in a permanent way?
thanks

[JSuchma]

Get the surrounding area to clean metal and spot weld with a MIG welder. Do not do a continuous bead; you want to keep the heat down to avoid warpage. Alternating welds as far as possible will keep the heat down. Slowly fill in the gap completely. Grind and fill with filler, then block sand into the surrounding metal.

[VCho455]

It's hard to say for sure from the photo but, it looks like it may have previous welds on it.

Have you viewed it from the backside?

My concern would be if the metal has rusted and become too thin to get a good weld on. If that is the case you may have to piece in some sheetmetal to get a good repair. Fortunately for you that isn't a commonly damaged or rusted area so if you wanted to replace it with OE sheetmetal, someone, somewhere has a rough fender that would have the piece you would need.

[Scarebird]

Another thought is to clean both sides of the affected area, drill the ends of the crack and spotweld a backer, then finish with putty.

[Steve Barcak]

Originally Posted by VCho455

It's hard to say for sure from the photo but, it looks like it may have previous welds on it.

Have you viewed it from the backside?

My concern would be if the metal has rusted and become too thin to get a good weld on. If that is the case you may have to piece in some sheetmetal to get a good repair. Fortunately for you that isn't a commonly damaged or rusted area so if you wanted to replace it with OE sheetmetal, someone, somewhere has a rough fender that would have the piece you would need.

no, t has not been repaired there before. the back side shows no repairs.

[Steve Barcak]

I thought this pic with a line where the tear is may be helpful.
I wonder how it happened? obviously stressed to the point of tearing but, have not seen others like this.

I appreciate the replies so far. I understand I can spot mig it. I just am not sure it would be a permanent repair. also, what caused this strange damage?

[Shiny]

The only clue I see is the deformation at the top of the crack (A). Something pushed that out from the inside.

But I agree that doesn't explain the rest of the crack. It doesn't make sense, given the absence of obvious stress in the plane of the sheet at that location. If the steel was brittle, a crack could propagate but it's not. Like a bullet hole, the puncture itself won't cause that crack to form.

The "stepped" crack edge at B is also unexpected... not typical for ductile low-carbon steel. Almost looks like stress corrosion cracking, but again, that makes no sense here.

It does appear the side of the crack following the line "C" is folded inward... is that correct?

This one will likely remain a mystery. Perhaps it was a manufacturing defect related to stamping the opening for the extractor? Or maybe it got ripped by something and was previously flattened by someone, "destroying the evidence"?? The rusted grinding marks tell you someone worked on it.

Because you can't explain it by "overstress" in that area, I personally don't think you should worry about the repair failing, but definitely weld it, even if it needs a patch.

Good luck with it!

[VCho455]

I firmly believe that getting welds without porosity is very important to preventing rust from forming from the backside and bubbling under the paint. It's one aspect of automotive sheetmetal replacement that never seems to get discussed.

After welding and grinding I like to blow air from the backside and look for it is coming through the welds. Rubbing some filler dust on the welds can help you spot the pin holes.

On parts with good access to the backside I primer and apply seam sealer as added insurance.

[Steve Barcak]

just to clarify- I've owned this car over 40 years. I've done all the body work and have painted it twice over the decades and have driven it myself for several hundred thousand miles. no one else has worked on it. the crack started small and grew. Will be doing body work, paint prep for its 3rd paint job during my ownership. I wish these fenders grew of trees as I would simply replace it but, I have not found a suitable replacement so, this needs to be repaired permanently somehow.