petrol tank rust

[JRidout]

Hi all,

Just started on the fuel tank and it looks really sound except when I took the sender unit out I noticed that there was some slight surface rusting inside. Now I don't want this in my fuel and unless I'm 2 years old I'll never get my hand inside so what do I do or what can I use to "Coat" the inside/remove the rust.

My dad said to poor a tin of Hammerite in and swirl it round and turn it up side down??? Ex Tank regiment which says it all...

JR

[sparky_spit]

Whilst not wishing to incur the wrath of the entrire Tank Regiment, I wouldn't recommend putting Hammerite in there, or any other paint that is not specifically designed for the purpose. Once it starts to flake off, and it will, you will have years of misery trying to keep the fuel pipes clear.

If the rust is very light surface rust, as you say, I'd leave it as it is. Fit a clear plastic in-line fuel filter and see how much or little rust you get in it. I bet there will be very little.

If it is heavy flakey rust, then I'm not sure. Some others on this forum have used special tank sealants, but I've no experience of them personally.

[Velocita Rosso]

Nine times out of ten the rust is created by driver/owners who dont fill up (to the top) regularly. Two gallon at a time for a few years for irregular users, will create the `tide mark` around the tank. So anything above the two gallons in the tank, will then start to rust. To prevent this regular topping up is needed. If my memory serves me right  there is a small amount of addidtive in the fuel to prevent corrosion(or there used to be when tanks were steel and not plastic)    

[JohnD]

VR,
Why should not topping up cause a tide mark -I presume you mean of rust - around the tank?  Water, either rain or car cleaning through the filler, or condensation sinks to the bottom of the fuel.

Steam clean it!  FInd a truck company - they often use steam cleaners.
And consider puttuing a handfull of gravel inside and giving it the shakin' stevens, to remove as much rust as possible.  Bikers wrap the tank in towels and put it in the washing machine (!) but that's not easy with a Spitfire tank. Concrete mixer? CoMmercial washing machine

John

[Velocita Rosso]

Instead of gravel....glass beads as in blasting

[Rich_s]

I should have done something like this with mine, had been stood for, we think, about 4-5years, didnt bother cleaning it out, just fitted an inline filter, but after having to stop on the hard shoulder for the second time to remove said filter that was solid with gunk, i gave up, i now just let the fuel pump filter catch the crap and clean it once a month, not the best of ideas i know, but works for me so i keep doing it.

rich

[Fizzy]

i put nuts and bolts and golf balls in my tank, bashed it about for a while, emptied it, repeated a few times. then fitted a filter which had to be replaced every couple of months to begin with as it drew through the remains of the rust. about 8 or 9 months in i seem to have got rid of most of it, and ive been on the same filter for about half a year now.

[James]

I was reading about oxalic acid the other day - buy £10 of it and fill up the tank - leave for an hour - empty it then steam it out?

[Gt6s]

jcarruthers wrote:

I was reading about oxalic acid the other day - buy £10 of it and fill up the tank - leave for an hour - empty it then steam it out?

I used acid from a dead battery and clean 1/2 in stones.
Washed out afterwards obviously.

I worked in a factory many years ago, we had machines called vibe machines these were used for cleaning / derusting metal components.
The media used was 1/2 in stones with diluted sulphuric acid.

[greenbonnie]

hi frost restoration do a motorcycl tank inside repair kit. you get chemicle cleaner. metal ready . then just pour the sealer in. tha tank needs to be off the car. as the tank needs to be rolled.this is ideal for a spitfire tank as about the same size as most bike tanks. it is a good kit having used this on my classic bike. just make sure you follow the instructions

[sparky_spit]

JohnD wrote:

VR,
  Water, either rain or car cleaning through the filler, or condensation sinks to the bottom of the fuel.

Not quite, condensation in (and on) fuel tanks does not always work like this in practice. We've got a 35 gallon stainless steel fuel tank on our boat. When it's half full, and after a warm day with a suddenly cool evening, the lower half of the tank gets slight condensation on the outside, and the upper half gets significant condensation on the inside. Admittedly it does run down into the fuel, and sinks to the bottom eventually, but there is always beading present on the inside surfaces above the fuel level.

It is of little consequence with a stainless steel tank and a marine grade water trap type fuel filter, but would cause obvious issues if it were a mild steel tank.

[Velocita Rosso]

sparky_spit wrote:

Not quite, condensation in (and on) fuel tanks does not always work like this in practice. We've got a 35 gallon stainless steel fuel tank on our boat. When it's half full, and after a warm day with a suddenly cool evening, the lower half of the tank gets slight condensation on the outside, and the upper half gets significant condensation on the inside. Admittedly it does run down into the fuel, and sinks to the bottom eventually, but there is always beading present on the inside surfaces above the fuel level.

It is of little consequence with a stainless steel tank and a marine grade water trap type fuel filter, but would cause obvious issues if it were a mild steel tank.

Thats the bit I was trying to get across....well said Froglet

[GTRoger]

572 wrote:

hi frost restoration do a motorcycl tank inside repair kit. you get chemicle cleaner. metal ready . then just pour the sealer in. tha tank needs to be off the car. as the tank needs to be rolled.this is ideal for a spitfire tank as about the same size as most bike tanks. it is a good kit having used this on my classic bike. just make sure you follow the instructions

Did that to my GT6 tank, only lasted for about 8 years. The 2 pack stuff came loose and blocked the outlet. Not sure what went wrong as the tank was cleaned before etc.

[JohnD]

Oxalic acid?
Sulphuric (battery) acid?
No,no, nooooo!
PHOSPHORIC acid is what you want.   The mineral acids are too aggressive on the metal. The other, like most organic acids, produces iron salts that are soluble in water, but iron phosphate isn't, so you get a hard layer of it on the steel sheet.   Excellent base for primer!

Phosphoric acid is the base of most 'Rust Removers' that cause it to go black, or deep blue, but they are rather pricey.  But "Milk stone remover" from a farmers supplier is about £10 for 5 litres, and is concentrated phosphoric acid!
It's phosphoric acid that gives Coke its' pleasant, acid 'bite', and allows it to be a rsust remover on its own, s the acid is an allowed food flavouring (!!!)

John

[Llessur]

Hammerite is definitely not resistant to petrol. I unwisely used this on my suspension turrets and the big bare patch underneath my front carb says it all...  :'(

[jango]

572 wrote:

hi frost restoration do a motorcycl tank inside repair kit. you get chemicle cleaner. metal ready . then just pour the sealer in. tha tank needs to be off the car. as the tank needs to be rolled.this is ideal for a spitfire tank as about the same size as most bike tanks. it is a good kit having used this on my classic bike. just make sure you follow the instructions

I have used this stuff works very well

[JensH]

Try to get access to a concrete mixer; use an old bike tire (inner tube) or equal to tie it up, and put some fine sand in. Let it run for a while, clean it with hot water, get it dry and put a little engine oil in, if you need to store it  8)