Let's say the tank is is 12x12x12. To make the body you would first bend a 1" lip on either side, then a 12" bend for the one side, then another 12" bend for the other. Shear size would be 1+1+12+12+12 X 12=38x12
Then for the sides you would add an extra inch for each side minus the thickness of the material. ie. the side would be 12+1+1 each direction minus 1/8 for a total of 13-3/4 shear size.
I don't have a scanner so I can't make you a drawing. Sorry.
Any fab shop would be willing to help on this.

The reason why we fold the ends is because it adds a huge amount of strength to tank especially when you figure on how much your frame flexes side to side.
Don't forget that these measurements are all ID so subtract the thickness of material for true OD.
I don't know the formula for american gallons but for canadian it is base x hieght x width divided by 277 equals gallons. Then minus 10% for fuel expansion. Very important on a hot day!

 

Thanks for the info! I'm thinking about using the following company to make mine, but I'm unsure of the cost as of yet: http://www.aluminumfuelcell.com/index.html

Has anyone else had any experience with any companies that make tanks?

 

While I was out at Hammers over the New Year's holiday, I saw a tank design that I liked. It was tapered for departure angle and built from 1/8 steel, serving a dual purpose as a skid plate well.

What my thinking is, why not keep the stock tank depth towards the diff and then taper it back to the rear bumper. That way I can easily install the stock fuel pump assy, without modifications.

 

That's exactly what I'm planning to do. My tank will not interfere with the departure angle at all, and I'll be using the stock fuel pump assembly. I've got an email into the company I put a link to, so we 'll see what they come back with.

Chris

 

If you're looking at steel tanks also, check out Chico tanks out of California. They might have a stock replacement...

 

I tried to find them online, but I couldn't find a site for them. Do they have a website?

Chris

P.S. Which material would be best: Aluminum or Steel??

 

www.transferflow.com

As to steel vs aluminum it depends what you're going to do with your truck. If you're rock crawling, you'll need to skidplate an aluminum tank whereas a good steel one should be okay. (I'd skidplate a steel tank anyways) Even if you line a steel tank, it will still eventually rust out, not to mention constantly plug your fuel filter along the way. Steel is cheaper, stronger...
I work will aluminum all day so I'm kind of biased. It's easy to repair or modify. Your call dude.

 

I was hoping to use aluminum for corrosive purposes and then have a thick skid plate underneath it for bashing rocks, although I've never really hit anything that high up, but it's definitely possible.

Chris

 

A good skidplate I think would be 10g steel. I would make sure that you've got about an inch of gap between it and the tank for a real good hit. Make sure that it isn't mounted to the tank either.

 

It depends on how you line the tank, I plan using a product made by a company called kal-Gard. http://www.kgcoatings.com/

The product is Gun Kote, I've used this product on many different projects, very tuff and resist rust. If I fabricate a fuel tank, I will apply this to the inside. Here in SoCal there really isn't much of a rust issue with fuel tanks. Even though a aluminum tank would be nice, adding a skid plate in addition, will negate the weight savings.

 

I was thinking a 3/16" thick skid plate underneath the aluminum tank not supported or attached to the tank. I wouldn't be making it out of aluminum for weight savings, but mainly corrosion instead.

Chris

 

I try to get weight on my truck! Not to the point of a 78' Ford super cab though...

 

3/16 is a bit overkill for a skid plate, all you need is 11 guage, which is just under an 1/8 inch. The tank I want to build will be made from 11 guage along the bottom and sides and much thinner across the top.

 

Well, at least I'll use 10 gauge for sure, and depending on the the probability of it actually getting hit by anything, I may go thicker or thinner for the skid plate. As far as the tank, I'll probably use 1/8" aluminum for the whole thing to make it easy. We'll see though!

Chris

 

Okay, so here's what I've decided to do, but I still need a little help. I'm going to build the tank out of steel. First, I'm going to cut and redesign the rear crossmember to make it higher up and stronger to upward movement by bracing it with some forward supports to the top of the frame too. This will help with my rear bumper not flexing upward as much when landing on a big rock.

So, after the crossmember is redesigned, I'm going to build a simple rectangular tank that will fit as far forward as possible, hopefully fitting in between the rear crossmember and the frame that the springs and shocks mount too. The tank has to be in the neighborhood of 15" deep so I can still use the stock fuel pump assembly, which shouldn't really pose any problem since it will be so far forward that landing on a rock is highly unlikely since the tires will be sticky past it, hopefully.

So, here's my questions:

1) What, if anything, do I need to coat the inside of a steel tank with so it doesn't corrode because of the gas?
2) I'm planning to use 1/8" steel for the bottom, and I'm wondering what I could get away with on the sides and top? I don't want to run 1/8" all the way around if I don't need to.
3) So, am I understanding correctly to say that the tops of the side will have a 1" lip to the outside that the top piece will lay on top of? This increases strength, right?
4) Do I bolt the top to the sides or weld it?

Thanks,

Chris

 

just TIG together some stainless into a real bling bling tank. that way you wont have to worry about it.

 

I'll be using a MIG welder and some useful comments would be much appreciated.

Chris

 

sorry about that

my dad built several custom tanks. he generally just peiced together some lightweight angle iron for a framework the covered it with sheetmetal. sometimes he would just use 1/8" steel and put it together that way. whatever you do, practice on a few peices first, to get the heat right so you dont burn through/warp the metal.

if the steel you get has some sort of coating on it, have it sandblasted or chemically cleaned before you use it. you dont want that stuff in your tank.

he never found a good coating for the inside of the tank to keep it from rusting. any paint or other coating would either flake off or gel up and clog the filter.

be sure to put a drain plug in your tank of some sorts, so once a year or so, you can drain the big chunks of rust out.

other than that, you should be fine, i know of one of these tanks that has been under daily use since 1975 by my grandpa.

however, the high pressure, in-tank design of your pump may give you much more greif than the mechanical engine mounted pumps that my dad was working with on the hotrods and his scout.

 

something else you could consider doing:

make a 2-peice internal mold of the tank using plywood.

use fiberglass to cover the two halves. separate them from the mold and then put the tank together.

be sure to integrate some mounting holes of sorts.

make a skid and go!

 

I have no idea what you mean on the second message, but as far as rusting, it looks as if the stock tank has a plastic box with the top cut off to keep the rust from entering maybe? Does that sound right?

Chris