Brazing Tank Fittings

Hello Kent,

I ordered your flux, video and handbook (all three products are well worth the money - even with the exchange rate to CDN$) so that I could learn to weld some aluminum fuel tanks together. 

After a lot of practice, it is slowly coming together. The skins of the tanks are made of .025 thick 6061-T6 as per plans.  However, the aluminum fuel fittings are very large (.100 to .120 thick) in comparison to the skin.

Question - Should I braze the fittings into the skin? Or select a thicker re-enforcing-patch (.060) and weld the fitting to the re-patch, and then braze the re-patch to the skin? Or weld the re-patch to the skin?

I see a lot of bungs on tanks on your web-site and was wondering how they were done, and if there was a large difference in material thickness. Thanks for your help.

Martin Bima
Winnipeg, Canada

The Tin Man Respondeth:

Flare the bung opening either down or up to allow the bung to seat snugly. It also helps to upset, joggle, or step the area outside the bung area in order to prevent distortion while welding/brazing.

Your tank is indeed thin, and will be a bit tough to join a big honking fitting onto. Use the geometries mentioned to help. Either brazing or welding will be fine, but remember to allow for good surface area contact when brazing..


See also:
What is the best welding flux removal technique for aluminum tanks?
Dents in Steel Gas Tanks
Tanks a Lot!

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