New Diesel tank

[nauticalnomad]

Back to reality. A tank on a slant is probably quite a good thing, as it would mean that any water or crud gravitates to one place, from where it is easier to drain or suck out. Even better - have a drainable sump on the tank.

Thanks NormanS, This what i have originally and i am looking to make it bigger to be able to hold more fuel..

 

[coopec]

. The most common failure mode of stainless steel welded structures is sensitisation, a form of corrosion caused by use of grades not suitable for welding. 304L or 316L should be used, with appropriate filler rods.

vyv-cox

I won't argue : you're the expert.

In the words of another poster this is what I meant

" Ike Ike is offline
Senior Member

Join Date: Apr 2006
Rep: 1616 Posts: 1,741
Location: Washington
Aluminum. Stainless is fine for small cylindrical tanks but not good for large tanks with lots of welds. SS suffers friom crevice corrosion which is usually in the weld seams. The more welds the more chance of crevice corrosion. Aluminum has it's own problems. Build a decent mounting system that keeps all sides including the bottom of the tank exposed to air and dry.

But the best are Polyethylene tanks. No corrosion, no seams (if it is a rotomolded tanks) and it isn't affected by anything in the fuel. Alcohol and other additives won't touch it. Thes tanks last virtually forever. But again, you need to allow for tank expansion (about 3% in volume) and the tank has to be well strapped down. The drawback? No baffling, unless you build a PE tank with welded seams. then baffling can be installed.
__________________
Ike

 

[vyv_cox]

'Senior member Ike' is similarly confused. Stainless steel does suffer from crevice corrosion, but not in a tank where there are no crevices What he is describing is sensitisation. It happens when stainless steel with a higher carbon content is welded. Carbon has a strong tendency to form carbides with chromium, which reduces the chromium content of the steel adjacent to the weld and leads to local corrosion. The answer is to use metal with a lower carbon content, e.g. 304L and 316L, with filler rods that also have a low carbon content, or that contain other elements such as titanium and niobium that have stronger carbide forming properties than chromium.

However, I do agree that polyethylene tanks are excellent but custom sizes can be very expensive, a lot more than metal ones.