Re: [AMC-list] Interesting JB weld test

[Frank Swygert <farna@xxxxxxx>]

Could the JB Weld have been too thick? 220 grit isn't enough -- I typically use 50-80, maybe 100. It should have cured after 48 hours and not pulled apart under stress like that though. 

I'd still use a few rivets or screws then seal them with JB Weld. Safer than soldering! Or use solder to seal the rivets FROM THE OUTSIDE. Solder doesn't hold much as far as stress either. Great sealer though! If you insist on solder get some silver brazing wire and a MAPP bottle. The thin wire melts easy enough with MAP (hotter than propane, can use the same torch though) and will hold up under stress.

Don't worry about the ethanol, I've got a motorcycle tank patched with JB Weld that are several years old. It's had plenty of ethanol laced fuel in it. 

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Date: Wed, 31 Mar 2010 17:50:00 +0000 (UTC)
From: Wrambler <wrambler242@xxxxxxxxxxx>

Considered using JB weld to mount a sump wall around the pump in my Amercans tank.
So, I JB welded two pieces of Galvanized metal I had sanded with 220 grit sandpaper together.
They had about a 1X2" section JB welded together for 48 hours. They were bent in an L with the weld at the short side of the L, just like it will sit in the tank. At 48+ hours I twisted and to my surprise they immediately snapped and popped apart!
Took a little effort, but not nearly what I suspected!

What really surprises me is that the JB product failed in the middle of itself!
There was a layer left on both surfaces, so it bonded well to the sanded metal, yet failed to hold itself together!

I will obviously be NOT using JB weld inside the tank.

I think It may bond the larger 8" x 8" sump metal in and hold, but have read that there is some suspect that the ethanol in new fuels may attack the JB weld in a way older fuels did not.

Current plan is to attempt to solder the sump metal in.
I don't really want to drill holes in the bottom of the tank, nor do  want to weld or braze and disturb the intact galvanizing in this tank if I can help it.

--
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)

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