How would you repair this?

[Russ/40]

Apparently on an earlier fender repair, this edge was ground so thin that it cracked. How would this be best repaired? I'm sure there will be different opinions, and I'd like to hear them all.

[tbirdtbird]

TIG would be sweet

[ford3]

remove that piece allowing an inch or so above and beyond it cracked piece, then stich weld in another piece from a donor fender, i dont think you can weld on that fender because it was ground so thin that it cracked, its very hard to weld on very thin metal with out burning holes at the thin place

[MikeK]

I'll probably catch hell for suggesting this, but I would use AWS Bag-23 Silver-Manganese brazing alloy. It is 85%Ag, 15%Mn.

Tight solidus/liquidus range starting about 1780F, very fluid at 1900F, it will easily wet and flow into the cracked section leaving a very small fillet. Much stronger than the steel when finished, and ductile enough to take some dolly work to make corrections after.

It contains NO copper, zinc, or cadmium, so the problems known to using standard yellow brazing alloys under paint are non-existent.

[Russ/40]

Originally Posted by MikeK

I'll probably catch hell for suggesting this, but I would use AWS Bag-23 Silver-Manganese brazing alloy. It is 85%Ag, 15%Mn.

Tight solidus/liquidus range starting about 1780F, very fluid at 1900F, it will easily wet and flow into the cracked section leaving a very small fillet. Much stronger than the steel when finished, and ductile enough to take some dolly work to make corrections after.

It contains NO copper, zinc, or cadmium, so the problems known to using standard yellow brazing alloys under paint are non-existent.

Mike can you source that for me? I would TIG it if I had one, but don't.

[MikeK]

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Originally Posted by Russ/40

Mike can you source that for me? I would TIG it if I had one, but don't.

Russ, I have ordered it from two different welding suppliers in the past. It was 1/16" stiff wire from Handy & Harmon. The 85Ag/15Mn stuff I used is also known as Silvaloy 852, Silvaloy, Z85M, Braze 852, and BAg-23. I'm sure there are other high silver, high fluidity braze alloys that you could use. Just avoid cadmium and zinc bearing alloys if you want to paint over it. I mentioned this stuff because it is very fluid and would fill your crack without messing up the crimp serrations on the bead- if your skill level is up to it. Last time I bought some was almost 4 years ago, and it wasn't cheap then, about $50 for an ounce.

[d.j. moordigian]

Originally Posted by MikeK

Russ, I have ordered it from two different welding suppliers in the past. It was 1/16" stiff wire from Handy & Harmon. The 85Ag/15Mn stuff I used is also known as Silvaloy 852, Silvaloy, Z85M, Braze 852, and BAg-23. I'm sure there are other high silver, high fluidity braze alloys that you could use. Just avoid cadmium and zinc bearing alloys if you want to paint over it. I mentioned this stuff because it is very fluid and would fill your crack without messing up the crimp serrations on the bead- if your skill level is up to it. Last time I bought some was almost 4 years ago, and it wasn't cheap then, about $50 for an ounce.

Mike,...are you using "Stay-Silv"? Russ, I would think, should know
this information...

Dudley

[MikeK]

Originally Posted by d.j. moordigian

Mike,...are you using "Stay-Silv"? Russ, I would think, should know this information... Dudley

Dudley, The Stay-Silv series of alloys from Harris are all phos/copper variants primarily for joining copper and brass (HVAC). I've used most of them over the years, but they are not for steel.

Harris does have one readily available alloy from it's array of Silver based products, Safety-Silv 56 that specifically is for steel-steel joints and has very high fluidity. I've used it to put broken-off mounting feet back on 10 Hp 3 phase reefer compressors. If it holds there, a fender bead is no problem. It too will work to penetrate the fender bead crack shown by Russ without overfill into the serrations, but with caveats: The alloy is Cu22%, Zn17%, Sn5%, Ag56% It does contain zinc, and will produce white dust (ZnO).

The moderate temperature for Safety-Silv 56, ~1200F is less than the self-clean temp for steel and will require a borax type flux. With the zinc fume dust and borate residue this alloy, also known as BAg-7, will require careful cleaning and light abrasive blasting followed by an epoxy primer to ensure long-term paint integrity.

The BAg-23 alloy that I initially mentioned will not have the zinc problem, and at 1900F will completely reduce any flux, if used, to inert glass and will do fine with abrasive cleanup followed by any primer or filler.

It was because of my perceived need to preserve the bead crimp serrations and integrity of the single bead wire that I did not jump on the TIG bandwagon for this particular situation. If it were a stress crack elsewhere I'd either TIG or gas weld it.

Of course, I'm no expert. I've seen guys who could TIG the lid back on a can of beans and it would look like it never saw the can opener.

[John Duden]

I had something similar happen. I cut a section out of a donor fender and tack welded it in place. I then used a copper strip and welded/ melted it together slowly so it would not warp. then ground it all back down. For the wire inside I could not repair it so I took a piece of metal about 1/2 wide and about 1/8 think and bent it in the vice to the curve of the fender. Then layed inside of the bead and welded it. Now it does not have the weak spot where the fender usually cracks and bends
John

[Mike V. Florida]

This is how I would repair it,



Repairs the beaded portion of the fender. Has wire installed as original.

[d.j. moordigian]

Originally Posted by Russ/40

Apparently on an earlier fender repair, this edge was ground so thin that it cracked. How would this be best repaired? I'm sure there will be different opinions, and I'd like to hear them all.

Maybe I'm not looking at this correctly,......

Is this the inside or outside of the fender?
Were is the reveal, the little 3/4" doodad above the bead?

[Russ/40]

This is the front of the fender, just inside the longitudinal crease. The involved area is small enough to make me hesitant to upset any sheet metal, and the inner wire is fully intact. This is otherwise a very sound fender.

[Seth Swoboda]

TIG weld it.

[d.j. moordigian]

Yep,.....I agree, TIG...

[28ACoupe]

I concur, Tig weld that puppy.

[Fred K-OR]

I think my fix would be similar to Mike's or maybe it is the same because I don't know that much about selection of rods. If you don't have TIG, which I don't either, I would just braze it with a torch. Brazing is a lower temp than most welding and should not cause any distortion of the fender.

But my rigs are drivers and not show cars. So it depends on what you need to have.

[tbirdtbird]

just remember once brazed it can never be welded....unless every spec of braze is ground off

[Fred K-OR]

Originally Posted by tbirdtbird

just remember once brazed it can never be welded....unless every spec of braze is ground off

Good point. Like I always say, I am not an expert on this type of thing.

[Russ/40]

Thank You Mike!