Rusty Petrol Tank - inside

[Stevie1262]

No doubt this has been done to death but thought I would ask anyway....after getting my ‘it’s ready to run when the Magneto is timed’ New Purchase home ..and finding a lot to do I am now looking at a very rusty petrol tank interior ...barnacles of rust...and covered in what looks like oil...so I used a gallon of vinegar and some salt for a couple of days then finished off agitating with a handful of nuts and bolts now it’s been soaking with dish   washer tablets to remove any grease or   oil ....so question is do I seal now or not ? And if not any other options...My gut feeling is not to seal but as the clean Steel is now ‘cratered’ that it will begin to rust...any advice appreciated ....( a brand new carb as well and it’s full of rust and oil ....sigh!)

[Greybeard]

I sealed my tank using POR15 because the tank came back from the platers with light rust. I did try cleaning it with vinegar and shrapnel but wasn't happy with the result. I was not aware of people's negative experiences with tank liners at the time. It's six years since I lined the tank and it appears absolutely fine. Mind you, in the UK we are not getting the amount of Ethanol mixture that other countries have.

[Sav]

Ethanol fuel absorbs water with the inevitable result on any bare metal in the tank, seal it and prepare with a rust curative.

I used an alkaline cleaner and a  rust buster and then Tapox ethanol proof sealant. Vital you ventilate the tank well to avoid surface runs on the sealer.

[Slymo]

I like the POR15 tank kit. It comes with a cleaner, some phosphoric acid and the one pot coat. Used it on serveral tanks now and it has been good every time. If you are looking for a very non destructive way to clean off rust then 20:1 molasses in warm water has a phenominal effect. Leaves a dull grey clean metal finish but takes 8 to 10 days. Smells vile so do it outside. Thats 20 water 1 molasses btw.

[muskrat]

G'day Stevie.
I'd use a rust converter (never tried the molasses as I put it on my toast and porridge yummm) then line the tank with Caswell https://tinyurl.com/m5xyz9y (i'v had a couple of failures with KBS and Por15). Do the old nuts/bolts/screws and shake first then the molasses/converter then the Caswell.
Cheers

[Jules]

How on earth does molasses become a rust cleaner? whats in it? are you talking about normal shop bought molasses or??? 

[bsa-bill]

whats in it

Sugar

from my work days I recall Silage effluent (the juice from the ensilaged grass collected in large metal tanks) would clean any rust from the tanks, it of course is sugar from the grass.
We didn't just suck straw you know

[duTch]

 I bought 20Litres of molasses for maybe $5 ?( or was it $two) from the local sugar mill late '90's, works a treat, I have bucket up the back and just drop things in at random....needs changing now though....I still have about 15 litres of the 20.
 The items need rinsing off after, but brings it up like sandblast, trouble is then the surface can start to rust again, but wire brushes off easy..I did my tank with it, but became labour intensive, and still needed to rinse it out with Phosphoric finally gave up and just put fuel in it...

[muskrat]

G'day all.
In the 80's I had a produce store (stock feed). I'd buy molasses in 44gal drums for horse and cattle supplements. Bottling it into 2Lt containers (messy job) I'd have to lick my fingers. That's how I got the taste for it. Spose my gut and end pipes will never rust. 
Cheers 

[Worty]

Hear what you're saying folks but I just live with a bit of rust.  Bikes been running for 5k since rebuild and I've had no problems.

[Joolstacho]

Those who 'line'... pray you never need to strip it off!

[muskrat]

G'day Jools.
I stripped mine out a year back. It needed painting anyway. A mix of paint stripper and thinners with a big handful of nuts bolts and screws. Wrap tank in a dona/sleeping bag and throw in a cement mixer for a few hours. Might take a few goes.
Cheers

[Joolstacho]

Yes, the ones I've done took all that, but even after all that there was still a chemical residue in the metal grain that mitigated against doing a 'proper' repair with silver-solder to 'plug' pin-holes.
The residue will burn inside and the silver solder (or braze) won't want to 'take' to the metal.
I know chemical 'liner' (it's just epoxy or similar resin) is the popular easy way out, but long-term, it'll be headache upon headache for subsequent keepers.

[chaterlea25]

Hi All,

Those who 'line'... pray you never need to strip it off!

Just use some ethanol laced petrol

John

[coater87]

 It sounds like some people are having luck cooking liner out.

 I don't know if they are using 600 degrees or hotter, but I guess it works pretty well.

 Of course your paint, body work, etc are gone too. But if it was lined it needed work anyway probably.

 Lee