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Old 03-27-2014, 09:54 PM   #19
MikeK
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Join Date: May 2010
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Default Re: How would you repair this?

Quote:
Originally Posted by d.j. moordigian View Post
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.
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