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strength of welded aluminum tank.

Posted: Sat May 06, 2017 4:24 pm
by Oilman
I am going to build an aluminum tank to roll 3-400 gallons of oil off of a box truck into clients facilities. The tank will be somewhere around 16" wide x 3ft x 3ft. technically this size would hold 650#'s with a bit of headroom. I won't fill it up that much.

So I got to thinking about wall thickness and weld strength etc. I have plenty of .1-.125 thick (I think 6061-T6)

I may weld some angle on all the joints to add some strength and ensure none of the welded seams crack or break. Also to protect the corners from impact/bumps.

Maybe some internal stiffeners?

The dispensing pump on top will be vibration isolated.

Anything i might have missed?

Re: strength of welded aluminum tank.

Posted: Sat May 06, 2017 7:35 pm
by Otto Nobedder
The internal reinforcement (it could as easily be external, if space allows) is going to be important.

Those dimensions yield nearly 90 gallons (less with headroom), and at 6#/gallon you're pushing 500 pounds (considering headroom).

That said, with adequate reinforcement 0.1 - 0.125 will be sufficient, even in a 4XXX grade.

Steve

Re: strength of welded aluminum tank.

Posted: Sat May 06, 2017 10:38 pm
by exnailpounder
Otto does this for a living...heed his advice.

Re: strength of welded aluminum tank.

Posted: Sat May 06, 2017 10:51 pm
by Otto Nobedder
Oilman, I double-checked my math, and those dimension yield 89 gallons and change.

(motor) Oil is averaged at 6 pounds per gallon, thus my 500# estimate, allowing headroom.

Steve

Re: strength of welded aluminum tank.

Posted: Sat May 06, 2017 10:58 pm
by Oilman
The oil actually weighs about 7.5 lbs/gallon. So the tank would weigh full at 673 lbs +tank weight+pump and motor. The tank dimensions have more to do with ease of work. I may just build it with a smaller tank and a raised top section to get it up to work height. It will have a brake handle that must be held depressed in order to move it. (just in case someone trips and loses control) It will be used in stadiums and on college campuses.

I also plan on baffling the tank so a baffle or 2 would help reduce stress on the welds.

It will have a beefed up bottom structure.

I may just build some out of stainless in the future. Need to get a brake bender first.

Re: strength of welded aluminum tank.

Posted: Sat May 06, 2017 11:01 pm
by Otto Nobedder
7.5 #/G is a pretty dense oil. Immaterial to the question at hand. Your internal baffles should provide all the additional support you need, presuming two baffles across 36", stich welded being adequate, if done well.

Steve