welding aluminum fuel tanks

Date 08-29-2013 17:56

Got a press brake? Bend as many seams as you can,then bend flanges on the ends and in doing so you'll have a single longitudanal lap joint on the main body of your tank.Thats how I've done them,I've done corner to corner fillets too.Never purged a new tank,only tanks that were used and in need of repair.We bent flanges on the baffles as well.5356 welding wire

By Milton Gravitt (***)

Date 08-30-2013 11:29

Are you repairing a old fuel tank or making a new tank.

M.G.

By G.S.Crisi (****)

Date 08-30-2013 20:53

By the way Gianivelo describes his doubt, I believe he's talking of making new tanks.
Repairing used tanks would require rigorous safety precautions in order to prevent an explosion.

Non é cosí, Gian?

Giovanni S. Crisi
Sao Paulo - Brazil

By Tommyjoking (****)

Date 08-30-2013 23:27

Gianivelo

I would go with 4043 or 5554 both do well with elevated temps and fresh/salt water exposure. I have used common 4043 most of the time for AL fuel tanks with 5052 base alloy and others. Keep in mind these were tanks of 150 gallon or smaller and usually did not exceed 1/8 in thickness. All the tanks had baffles inside which helps reduce stress on the seams as well as preventing load shifts...these were wire welded in place while the seams were tig welded. The strength limitations of 4043 were never an issue on tanks of this size. Most small boat manufactures I know are working with 4043 fillers.

Here is a filler chart I refer to often when I need to figure something out:
http://www.alcotec.com/us/en/support/upload/Alcotec-Filler-Selection-Chart.pdf

By gianivelo Date 09-03-2013 19:12

Thanks for the help. I think I will go with the 5356 which is what i have on hand and yes these are new tanks, I would never repair a fuel tank. These tanks will be around fifty gallons. I plan on bending two of the corners.
Thanks again.
Gian Bongiorno
Berkeley CA>

By Stringer (***)

Date 09-06-2013 12:14

Baffle design pretty important on these squarish aluminum tanks to keep 'canning' from causing cracks.

By gianivelo Date 09-06-2013 14:45

I am making replacement tanks based on the previous design which had corrosion problems. I will copy the baffle design that was previously used. If I had my way I would make the tank from s.s. or monel but this for a racing sailboat and they want to stick with aluminum. I would think that I would try to avoid burn through and skip weld on the baffle welds to avoid cracks due to oil canning, how would you approach the baffles? Thanks
Gian