Best material to make a new fuel injected tank out of?

[WagonCrazy]

Would like to start a discussion of what the best material is to make a new fuel tank out of (and why).
Aluminum, Stainless Steel or just cold rolled steel.
I need to build (or have one built for me) a new tank for my Nomad project. LS1 engine, and I want a tank with baffles, sump area, and late model GM (Delco) in-tank pump in it.
And I want it bigger than 16 gallons
And I dont want it to hang from the cargo floor with straps...it will mount to the frame via some custom tabs/brackets
And I dont' want it hanging more than 2 inches below rear the bumper, but there's probably 8 inches total of dead space just below the cargo floor that can be used before you see it hanging below the rear bumper...
And it needs to fit in a wierd sized hole (due to the C4 swabar mounting over the frame)
Here's a pic...
(Note...the body is lifted from the frame about 10 inches here.)

DSCN2296.jpg

So I just want to know why to build out of any of these materials over another? I foresee a custom tank being fabbed up...
This Nomad will NOT be a polished show queen. It will be a clean driver when all is said and done.

So what say ye?

[chevynut]

It depends on what you want. Cold rolled steel will rust eventually, probably fairly quickly since water tends to condense in a gas tank. If you coat the inside, you could avoid that...if you coat it thoroughly. You would want to paint it outside too.

Aluminum could be used, but it tends to corrode as well although probably not as fast. CPP makes a fuel tank for Tri5s out of aluminum, but it's pretty expensive imo. A lot of fuel cells are made out of aluminum. It's not nearly as strong or stiff as steel or stainless, so you have to be careful how you brace it internally with baffles. Also the mounting brackets need to be strong because the fuel is going to weigh over 100 pounds (6 pounds per gallon). It is lighter in weight than either of the other materials, and it's probably in between as far as cost. If you polish it, it will dull fast over time, so painting may be the best bet.

Stainless steel is the best, imo. It won't rust, it's stiff and strong, and can be welded. It can be polished or painted too. But it's most expensive. The material alone for my tank was around $275 a few years ago. But you could go with thinner stainless if you aren't concerned about visible warpage.

I went with an in-tank Walbro 255 LPH pump. I built the pump unit myself, and it's all stainless...I wouldn't do that again. Both Tanks, Inc. and Rock Valley have pump units you can put into your own tank for around $225. IMO I wouldn't mess with an OEM pump unit. The sender can't be changed, if you want to do that. It' integral into the pump unit. You could add a separate sender, though.

I think you've seen mine many times, but here's some pics ....it's about 23 gallons, 14 gauge stainless all TIG welded and baffled. The baffles support the tank bottom so it doesn't bow downward in the middle. The baffles have holes drilled in the bottom and don't go to the top of the tank. It hangs 1.5" below the frame and the 3" exhaust passes between the tank and the frame.

[chevynut]

One more pic....

[WagonCrazy]

Can stainless be Mig welded? Or must it be Tig welded?

[567chevys]

Stainless steel can be Tig or Mig welded , Tig is a much nicer finish weld than Mig . Most people think that in order to Tig weld it cost's a ton to do. All one needs is a AC/DC stick machine and a air cooled tig torch (around $100.00) and a bottle of argon gas . Even some of the Mig machines can be hook up so one can weld Tig with them. If you need part numbers for the items let me know and I will get them for you

Sid

[WagonCrazy]

If you mig weld stainless, do you use stainless steel wire? I'm assuming so...

[567chevys]

Hi Wagoncrazy , Yes you are correct stainless filler wire will be needed , always use same grade or better to weld the base material never use lesser grade

Sid

[chevynut]

My tank is 304 stainless and I welded it with 308 TIG rod. You can look up a welding chart to see what rod is compatible with the stainless you plan to use. And yes, you can use MIG if you get the right wire and gas.

[WagonCrazy]

OK. Good feedback on the Mig Stainless quesiton. So to completely exhaust this discussion, let's say I got ambitious and bought some Mig stainelss wire that was as good a grade as the stainless steel that the tank would be fabbed out of, and lets say that I welded it all up with my little Lincoln 135 Mig welder (is it 100% argon gas for stainless?)...and lets say that since this is a tank that will sit under the wagon, out of sight for the most part...that I plan to grind any welds that look like bad and then just polish the whole tank up when done.

Is there any reason why it can't be done with a Mig welder vs. paying someone else to Tig weld it instead?

I ask this because my impression of Tig welding is when you want a very precise weld bead that is probably NOT going to be finished up, and just painted or polished...the Tig process lends itself to very precise looking welds. But is Mig any weaker? or more prone to leak if it was done properly?

Trying to see if I can do a custom tank myself for UNDER $500 including an intank pump setup...

Let's hear it from your perspectives....

[chevynut]

I built my tank for about $450 including the stainless sheet, bending, pump, sender, and all other hardware.

Process-Specific Advice

GMAW Electrode and Shielding Gas Selection
Use the smallest wire diameter feasible. A smaller wire takes less heat to melt, which in turn heats the metal less. A smaller wire also gives you more control over the weld bead and a better chance of recovering from mistakes because it has a lower deposition rate. That's why professional groups like I-CAR, the Inter-industry Conference on Auto Repair, recommend using .023 in. diameter wire for most collision repair work. For welding material 18 ga. and thicker, you may be able to use a .030 in. wire for higher deposition rates.
For welding mild steel, choose an AWS E70 wire in S-2, S-3 or S-6 classification. For shielding a shielding gas, always use a high argon-based gas, such as 75 percent argon/25 percent CO2 gas (commonly called 75/25 or C25). Argon carries less heat than pure CO2, and you'll get less spatter.
The two most popular wires for aluminum are ER4043 and ER5356. While the latter feeds more easily, choose ER4043 in .030 in. diameter to solve heat-related problems. ER4043 melts at a lower temperature and uses slower wire feed speed, often making it the superior choice in sheet metal applications. Always use 100 percent argon shielding gas.
For welding 304 stainless steel, ER308, ER308L and ER308LSI wires are compatible. For welding 316L stainless, you need a 316L wire. Use a "tri-mix" shielding gas consisting of 90 percent helium/8 percent argon/2 percent CO2. Note: Do not attempt to weld thin metal with flux cored wires. These wires use more heat because they require globular transfer. Unlike short arc, where the weld puddle cools every time the wire touches the base metal, the arc remains "on" constantly with globular transfer.

http://www.millerwelds.com/resources...FdEDtgodJ0o-zg

MIG Welding Stainless Steel

Stainless steel MIG welding does not require any special equipment. In the case of welding stainless steel, the biggest problem comes from the cord or liner of the welder. The trick when welding stainless steel is to keep the cord as straight as possible. Otherwise, the wire feed that feeds the weld joint will have too much friction due to stainless steel being stiffer then carbon steel. Think of trying to shove a wire hanger through a bent garden hose. Chances are if the hose is straight you can easily put it through. If the hose is bent, you will have difficulty. That is how stainless steel wire is in the liner of the welding cable. What happens is the wire is so stiff in the liner that it causes so much friction that the wire stops the feeding wheel from feeding the joint (literally spinning its wheels). The result is a fused MIG tip. That is when the wire stops or slows down to the point that the arc melts the wire up to the MIG tip and it welds itself to it. The other major problem is again the liner. If you bend the cord to much the friction stops the wire and the wheels that are feeding the MIG gun push the wire so hard that the wire having no place to go spooling up like a birds nest before it gets pushed into the liner.
MIG welding stainless steel is mostly done in a spray transfer or globular borderline spray. The reason behind this is that stainless steel does not do to well with short circuit transfers. The short circuit transfer and globular have the wire actually hitting the metal, splashing and splattering, and that also causes friction on the liner.
Welding stainless steel requires a high percentage of Argon used in the gas mixture. If it is a critical joint that will be x-rayed, any disturbance in the transfer will cause flaws. Spray is a smooth crackle-free transfer that has no metal being violently transferred. Spray transfer also keeps spatter to the bare minimum. With stainless steel spatter is extremely difficult to clean. The pictures below on the left is a weld I did using ER 308L wire, C2 gas, with a globular boderline spray transfer. I also used the same settings for the picture on the right. One of the great things about MIG welding is, I did not have many restarts. The long welds are about 3 feet between the restarts.


http://www.gowelding.org/MIG_Welding.html

http://www.lincolnelectric.com/en-us...ss-detail.aspx