What (if anything) can you do to prevent the inside of a mild steel fuel tank from rusting. In theory the bottem and sides should not be too bad in the long term, but sooner or later the top will surely rust out from condensation in the tank and from not being covered by fuel (oil) like the sides/bottom.

por fuel tank sealer system if your that concerned available from frosts

.............a good solution, but I use a cheap (well, free) one here at work which is to zinc phosphate the tank. It prevents corrosion on the inside and gives a good base for paint on the outside.

Very cheap and easy if somebody nearby has a Zinc Phosphate tank, you just degrease it and hang it in the tank for 10 mins and it's done!

make it out of stainless? I am but only because I have a couple of sheets of it.
-ya I know its heavy-
Dale

When this one rusts out, I will probbaly make the next one from stainless or aluminium. Untill then, i've got plenty of mild, and a welder set up for welding mild.

I take it from the responses that generally no one uses mild or doesn't worry about it rusting?

stainless still weights the same as

normal steal..

i also maked it from stainless steel (inox)

(see pics)

Could make from ally but it is more expensive.... and the equipment needed
wasn't nearby..

(i have welded my tank with the good old pins (electric) )

TKS

I have made a couple of mild steel tanks, and phosphated them as I said, which stoppped them rusting no bother.

Fuel actualy dissolves zinc phosphate over a period of time, so you are mearly slowing the rust process down, although the section dissolved is normally covered in fuel so its not an issue.

However, zinc pohosphate has been known to clog injectors up - probably not a problem if you run on carbs though.

Also, you may see systems that coat the inside of the tank with epoxy - that breaks down over time as well.

[Edited on 17/5/05 by silex]

never knew that! A lot of production car fuel tanks are zinc phosphated so I can only assume that the injector clogging thing is not a big issue. Certainly I run on injection with no problems (yet!!!)

I didnt treat the inside of my tank with anything and there are no signs of rust yet.My theory is that to be able to rust it needs to have oxygen in there which is mostly displaced by the fuel vapour so not much chance of rusting.I have only ever seen tanks rust from the outside and normally on the top where water is able to sit.
Paul.

If water gets in then the tank can rust from the bottom, as thats were any water sits.