Anyone made a fuel tank from scratch?

[cowboy]

The tank on my 35 Pontiac is rusted beyond repair, I'm going to have a crack at making one from scratch. Can I use plain mild steel or do I need a special grade of steel?

[Sprint]

use stainless if your going to that trouble, no way id use mild steel cuz rust, states prob have repo's.

[XB GS 351 Coupe]

Would not use mild steel, aluminium or stainless IMO.

[cowboy]

No repros for this car sadly. The car is 100% original, stainless/aluminuim just wouldn't be right. Also, I can't weld stainless or ali and I'd hate to think what it would cost to have someone else make it, it isn't just a basic square. Steel can work fine, this one is only rusted because it was stored empty for 48 years, I have steel tanks that are close to 90 years old and still in service.

[cs123]

I could be wrong but factory tanks are gal dipped mild steel aren't they?

You could always treat the inside of your new tank with POR or KBS to stop corrosion, not sure about the outside.

[XP6]

I reckon they'd only be mild steel maybe with some sort of electro coating for a factory tank, you could always use one of those tank restoring paint kits to coat the insides and paint the outside to match the underside of the car.

[pottery beige]

Making something fit from something else sounds heaps easier

[madmelon]

I have built two fuel tanks from scratch for Formula SAE using sheet aluminium. It's not an easy job- you have to ensure it's completely watertight, which in our case involved submersion and pressurising very gently (with my mouth) to trace leaks. It was very time consuming fixing all the leaks, despite being welded by a professional welder (university workshop employee- I did all the sheet metal work.) Under no circumstances should you try to weld if after putting fuel in it- apart from the risk on an explosion or fire, traces of hydrocarbons release hydrogen gas in the arc which causes hydrogen embrittlement of the weld and subsequent cracking.

Untreated, mild steel in not a great material for a fuel tank- any water that can get in either by leakage or as part of an ethanol blended fuel will cause corrosion which will get sucked into the engine eventually.

[Stefan]

Originally Posted by pottery beige

Making something fit from something else sounds heaps easier

Spot on, some early XAs use XY tanks with some brackets on the side as they are narrower.

Measure hole, take a walk in a wrecking yard with tape measure, pen and paper.

[cowboy]

Thanks for all the replies guys. Some more research has shown that the old tanks were made from terne plate, steel plate coated with zinc and tin to prevent corrosion. This isn't made anymore so it looks like I'm back to stainless or aluminium. The car is 78 years old and 100% original so I don't really want to jam another tank in it, I'd rather take the time/money to make it at least look correct. I have a TIG, maybe it's time I learned to weld stainless.

[Silver Ghia]

Thought about using POR15 tank sealant? Or is the tank too far gone? The process also treats the rust and coats it.

Or alternatively if you make a new tank and you're unsure if its leakproof, you could coat the inside with this sealant.

Edit: Sorry, XP6 already has suggested this....

[cowboy]

The tank is way too far gone for that unfortunately, it is good for a pattern only.

[madmelon]

If you can TIG mild you can TIG stainless. Do some practice on scrap of the same material. Drop the current to about 1/3 what it is for mild steel. You'll need to shield the reverse side of the weld or it will turn to nasty black cr@p. Target weld appearance is copper or gold colour. Dark grey means you've burnt the chrome out of it and it'll rust at the weld. A little bit of practice and you'll pick it up I'm sure.

[cowboy]

Cheers mate. How do you shield the reverse side of the weld? I have plenty of stainless scrap to practice on.

[gregaust]

Isn't the tank filled with argon when it is welded? Any stainless weld should have the welds treated after with a pickling paste. The heat from welding brings out oxides I think it is that will show as a form of corrosion on the weld. Or something like that.


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[The Yeti]

Is it an Aussie car? If so is it te same as the equivalent chev?

Might give you options of Repro or a good or repairable 2nd hand unit

Do you have dimensions? I have a 37 tank on the shelf in my parents shed, I would assume that as everything else changed between 36 & 37 that it's different also but it's worth looking into

[SumoDog68]

Brown Davies in Bayswater makes fuel tanks from scratch - I used them for my long range tank , good quality work and good customer service. I would give them a call as home made fuel tanks are probably not worth a risk.

[LoudPipes]

I have no idea what a ’35 Pontiac is, so this is just a stab in the dark.
Are these tanks anything like you’re looking for?

http://www.carparts.com/results/?N=0&uts=true&searchType=global&Ntt=pontiac+fuel+t ank

[cowboy]

It is an Aussie car Yeti, I had a look under my 37 and it looks fairly different but might be worth a look anyway. I have the feelers out for a tank or pics of 35-6 Chev, Buick, Olds tanks but as you no doubt know, 35-6 models are rare regardless of marque.

Here is the tank, dimensions are approx 29" wide, 17" deep and just under 8" high. I have only just got the car, the tank was cut by the previous owner.





This is the car.

[monte.b]

If you go aloy id go about 4mm marine grade plate ,i made one for my 32 ford rpu ,it was 5mm but a bit of an overkill ,2baffles will help any cracking ,in stainless id go 2mm 316 marine grade ,doesnt brown off and polishes up a treat ,you can buy early ford repro ones but they dont look like yours

[Bill M]

Terne plate steel was a common material used for fuel tanks of that era.
Terne is a composite coating of lead/tin.
Have you had the tank evaluated by a specialist?

http://www.ftrs.com.au/fueltanks/fueltanks.php

Bendigo swap meet is coming up soon...
Good luck!

[Jallopy]

"Brown Davis" use 2mm steel when they make the long range tanks for the 4wd vehicles.

[cowboy]

So I spoke to a specialist who makes and repairs vintage tanks. Mild steel is apparently fine (clean steel - no mill scale), can coat with a tank sealant like POR if I'm worried, paint the outside. Looks like I have some work to do.