Aluminum Boat Gas Tank?

[rhino51]

I'm going to build a new gas tank for my boat. I not really sure what thickness of aluminum to use. The gas tank will hold 12 gallons of fuel. Any Suggestions?

[aametalmaster]

Are you going to TIG or Mig it?...Bob

[rhino51]

tig

i'm going to tig weld it

[FusionKing]

YUP
use 5052 at least .100 thick and weld it with 5356.

[corbyndad]

Round or square? Square I'd go a little heavier than round. I like to go a little heavier than needed so maybe .125 5052 if square or even round. My 2 cents

[bostoncanadawelder]

I would use .125 with the gas tank and also TIG and mig weld it with and bondo the edges. You need to test it for leaks before hand.

[MMW]

I would use .125 with the gas tank and also TIG and mig weld it with and bondo the edges. You need to test it for leaks before hand.

So you would tig it, mig it & bondo it? Seriously?

Fusionking is correct, but you can use .125" also if it is easier to get.

[Bistineau]

Is this going to be a portable tank or a permanent install? If a permanent install, I would go as large as practical, as boats tend to burn fuel at a pretty good rate, and the more fuel you have the longer you can stay out on the water. But a portable tank starts to get pretty heavy after 12 gallons. Gasoline weighs about 6Lbs. per gallon, so your looking at 72 Lbs, plus the weight of the completed tank. Go over all your welds very thoroughly before adding fuel. Even if you test for leaks with water first, be aware that gasoline molecules are smaller than water molecules. Meaning if, even though it doesn't leak with water in it, don't mean gas won't find a small pinhole if there is one. Double or triple check it for leaks after it's filled with gas. After filling with gas it will be too late to go back and do anymore welding W/O serious purging effort and major cleaning, which might not get out ALL fumes. BOOM BIG TIME.
Even BONDO may not hold up as a permanent fix when exposed to gasoline for extended periods, check it often in the BONDO area if you end up using it. Does anyone on here KNOW(not just THINK it does) if BONDO will hold up to exposure to Gas?

[SundownIII]

Typical thread.

OP asks a question and gets an answer from a "pro" who knows what he's talking about and gives the correct, detailed explanation.

Then the "peanut gallery" chimes in with a bunch of mumbo jumbo BS (mig, tig, bondo----yeah, right) and a bunch of other irrevelant crap.

Just confirms the old statement:

If you can't dazzle them with brillance, you can baffle them with bullsh1t.

[Ronnie]

I would use .125 with the gas tank and also TIG and mig weld it with and bondo the edges. You need to test it for leaks before hand.

Bondo??? What is that all about and then mig as well as tig??This needs clarification! "LOL" Sorry "TOO MUCH BS".

R

[lamename]

The way I would do it is, 1/2" 5052 using 4043 filler applied with a caulking gun. Make sure you duct tape the inside seams first. Before pressurizing to 125psi smear a good amount of jb weld to the outside corners. Fill with gas and pressurize. That's how I would do it. However I don't own a boat or welder.

[H80N]

The way I would do it is, 1/2" 5052 using 4043 filler applied with a caulking gun. Make sure you duct tape the inside seams first. Before pressurizing to 125psi smear a good amount of jb weld to the outside corners. Fill with gas and pressurize. That's how I would do it. However I don't own a boat or welder.

Funny... but not that funny...
we probably have enough clueless neophytes in the audience...... so a few might miss the joke and take that for gospel...... then pester you into the hereafter with truly lame questions......

[wrench3047]

JB Weld, is spray or short arc?

[flukecej]

JB Weld, is spray or short arc?

Be aure to get the MARINE JB Weld being that this is for a fuel tank on a boat.

[gtsuper]

Help the guy!

I did mine this way 5052, corner welded with 5356 AL. Dynasty 200 dx set at 150 amps, 70 bal and 125 freq. ,with a on off button on the water cooled torch. Tacked and started at 1 end to the other, paused for cooling.
Then presure tested thru the fittings at 4 lbs PSI, soaped tested and found 2 pin holes. Ran over them and all is fine. Not sure if this guy is BS or just needs HELP???