What should I get a fuel tank made of?

SNIP

Fuel "Cells" are generally made specifically for this type of restoration or high performance vehicles. They look plastic but I'd guess they are multi-wall units and may contain titanium. ...Well.... Maybe not Titanium. :)

Hey J,

Actually, 5052 H-32 sheet aluminum is a recommended product for fuel tanks. Comes in at least .032", .040", and .050" standard.

Take care.

Brian Lawson, Bothwell, Ontario. XXXXXXXXXXXXXXXXXXXXXXXXXX

I'd be using stainless - but I have relatively good source of surplus stainless sheet- just have to check regularly to see that they have, and a good friend who welds the stuff all day.

Dito for aluminum - my second choice.

I wouldn't trust my welding to make a fuel tank/cell unless I was as good as say, Ernie. Your safest option is to purchase a racing fuel cell.

Exactly. Consider do you know the baffling concept ? where and how to put the crazy - but works - swinging pot to measure the amount of gas... electricity in the gas tank.

Martin Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH, NRA Life NRA Second Amendment Task Force Charter Founder

Steve Walker wrote:

What are you talking about?

What about sheet brass? Solder together - no sparking, no rusting, etc.? Ken.

The little gismo that sends a signal to the gas gage. It is a pot that connects to the + and - supply and the center wiper is on the float. You know - when you run out of gas and the float goes all the way down and rattles a little on the metal...

The baffles are to keep giant waves from surging side to side in high G turns. They chop waves up to quell movement as a mass.

Martin

Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH, NRA Life NRA Second Amendment Task Force Charter Founder

jtaylor wrote:

I'm using a selsyn, but yes, there is a swinging arm...were you merely asking to make sure I didn't place a baffle in the way of the arm's arc?

I knew that. On the tank as it is, when full, fuel spills out the filler on left turns (driver's handbook warns about it).

That little wirewound potentiometer inside the fuel tank varies current flow to the gas gauge to indicate fuel level, and most such systems are accurate to about 30%. That little pot makes sparks at times, inside the tank, and isn't sealed against fuel. The theory is that fuel vapours in the tank are too strong (more than 8:1) to burn. Works OK unless the tank is drained and left open and the concentrations get low enough to go boom. "Empty" tanks can be dangerous. Our airplanes have the same setup. Larger aircraft have capacitance fuel level systems, with no moving parts, and are much more accurate. If I was making a tank for an automobile I would use plain old hot-rolled 20 gauge steel sheet, TIG or MIG welded. Epoxy paint on the outside for corrosion resistance.

Dan

Yeah, tell that to TWA FLight 800.

Excuse, please, but what does insulation worn off of wiring have to do with epoxy paint on aluminum gas tanks?

Oh, and when you top-post as you have done, it makes quoting with context inconvenient. Is that your intention?

I'd use external strain gages or a load cell on the bottom support for gas measurement. Martin [ but they cost more and won't be considered ] Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH, NRA Life NRA Second Amendment Task Force Charter Founder

Dan_Thomas snipped-for-privacy@yahoo.com wrote:

I'd expect that fuel gages are designed along the lines of the "intrinsically safe" sensors that are used in explosive atmospheres in industrial settings. This is accomplished by limiting the current, voltage and energy storage (inductance, capacitance) in the device to a level that's incapable of causing ignition.

Ned Simmons

Nope. They're just scratchy, sparky wires like he said.

Also they put dc brush motors in fuel tanks. Immersed in gas to lubricate them. Scary but it works.

Jim

Differential pressure guage, from top vent to fuel outlet reads fuel column hight quite accurately. The sensors are pricy from "prime" suppliers, but I've picked up sufficient quantity for my use, brand new surplus, for a VERY reasonable price.

A scratchy, sparky instrument may still be intrinsically safe as long as the energy available is insufficient to ignite the flammable atmosphere, i.e., little sparks are OK.

Yeah, I worked on the automation for the powder metal gerotors in an early Bosch submersible fuel pump. Freaked me out til I realized the motor is always supposed to be submerged. But what happens when you run out of fuel? A fuel gage can be designed to operate with limited current - I think the limit is in the neighborhood of 1-10mA for most intrinsically safe stuff at low DC voltages - but of course that's not going to run a fuel pump. Is it assumed the pump will always be submerged, or is it really that difficult to get the vapor in the tank within explosive limits? If so, can you weld with abandon on a tank as long as it's got a bit of gasoline in it?

Ned Simmons

Simm> >

No problem with pumps or gauges in the tank since the fuel vapor level is so high it will not ignite. Just not enough air in the tank to cause problems. As to welding on tanks I do it a lot BUT this is after they are evacuated using inert gas and flushing it real well. Every fuel gauge I have seen uses nothing more than a variable resistor element with an open wiper. Most are set up on the ground side instead of on the positive side of the system.