[Hollywood1]

Here is a picture of some recent lap joint welds. I bent two u's out of .090 5052 for the fuel cell. Should work out nice. Thanks for all the tips stay tuned. John

[Hollywood1]

A picture of more progress on the fuel cell.

[Rick_H]

@superiorwelding

[TamJeff]

tamjeff
in the first photo am i seeing two pieces?
the one on the right with a flange on top?
craig

Those pieces to the right are a stack of four pieces of 11 (5052) gauge cut to the shape of the pre-bent, 3 sided shell. Two are for slosh baffles and two are end caps. I stitch welded flanges onto the baffles to save from having much in the way of distortion in the central part of the tank. The flanges allow for stitch welding a lap joint instead of alternating inside corner stitches if welded in without flanges. Lap joints weld so much faster since you don't have to wait to penetrate all the way into an inside corner and half of the heat is absorbed by the flange, which also acts as a broad stiffener of sorts. I was done with that tank, including bungs, in under 4 hrs. It was a typical, gotta have it ready for the holiday job and that was on the Friday night before.

The tanks I build end up being installed semi-permanently in the bilges of boats with either glassed in, or sealed in decks so, you really have to get it right the first, and possibly only time, which is why that one is coated with coal tar epoxy, because it most certainly will be exposed to salt water, and possibly, some anaerobic conditions as well.

There is a great tank builder here in Tampa and I always refer people to them but this guy was insisting that I do it or I would have gladly passed it on.

[TamJeff]

I'll remind everyone that TamJeff has extensive experience with aluminum, including difficult alloys and surface treatments.

You CAN build a fuel tank like this, but unless you have a bore-scope to examine the inside corners, you should do much practice first on scraps you can examine the back side of. With fuel, contained in the same vehicle you're riding, you want high confidence. The visible surface finish of the welds is only a cosmetic issue, and does not reflect the quality of the weld.

Steve S

Many people take aluminum lightly, but it really is a different field of expertise worth specializing in, I think. I started out welding all materials, but the void in the industry really seemed to be with aluminum. There is a full fledged welding fab shop not more than a quarter mile from us and they often bring their aluminum work to me, and our shop is rather crude comparatively. Like anything else, if you don't do it every day, you may find that you have to re-learn at each task, especially if the materials are different each time and they need the welds to be decorative as well as sound. They just don't have the time or scrap materials to practice on each time before moving onto the money welds. Their steel work sure is top notch though.

[Superiorwelding]

Rick,
Thanks for sharing that. I guess I just don't normally order 6061 when I know I am going to bend the material so I don't have the experience with it in that regard. I did see the other day where someone tried to bend 3/16" 6061 and failed miserably. All in what you know and technique I guess.

TamJeff,
I agree with your statement that aluminum is "a different field of expertise worth specializing in" as I see the same thing here. We have a few shops that just don't want to do it. And some who should't do it. I don't claim to be a expert at alum by any means but I do enjoy welding it and SS the most as both require a different skill set and knowledge base.
-Jonathan

[Rick_H]

It wasn't my first choice...I would have ordered 5052 but my coworker didn't specify so our buyer got 6061, so I delt with the cards I had. I've done 6061 1/4" 45° or so any more and it starts to crack