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Braze it or silver solder?

Posted: Thu Mar 23, 2023 5:13 pm
by Metal Manipulator
I have a new fuel tank for a car I'm working on and I want to add a drain. I have a steel bung and looking for opinions on whether I should braze it or silver solder.

Re: Braze it or silver solder?

Posted: Fri Mar 24, 2023 9:30 am
by cj737
I’d be surprised if the tank was steel and not alloy. If it is indeed alloy and your bung is steel, that’s not a good marriage of metals near fuel due to corrosion attacking the steel and the galvanic corrosion between the two metals.

If the tank is alloy, get an alloy bung and weld it. You don’t want ANY seepage potential.

Re: Braze it or silver solder?

Posted: Fri Mar 24, 2023 8:18 pm
by Metal Manipulator
Thanks for your reply. It is steel, it is a aftermarket tank for a mid 30s car made by Tanks Inc.

Re: Braze it or silver solder?

Posted: Sat Mar 25, 2023 10:31 pm
by drizzit1aa
Why would you not just weld it? If the tank is too thin for you then maybe silicon bronze, it with TIG. Like cj737 said, that could cause a Galvanic corrosion. Here is a link to what that is.
https://www.appmfg.com/blog/4-facts-on- ... -corrosion

Re: Braze it or silver solder?

Posted: Sun Mar 26, 2023 9:45 pm
by Metal Manipulator
Thanks, I do understand about galvanic reaction. I don't have a tig but I have tig welded some but very little. I don't have enough experience with one to be any good at it. I kept contaminating the tungsten.