Getting rid of rust from inside a petrol tank.....tips please

[exrm193]

I've bought an old bike to tinker with over winter. The fuel tank is FULL of rust. It's not been used since 1990!
Anyway, can anyone recommend a de-rusting technique that has worked.

Cheers

[redbikejohn]

Most will say use acid but I wanted to keep the old paint so I used electrolysis method. Fill tank with a solution of water mixed with one tablespoons of washing soda crystals per gallon (more or less). Connect negative of a large battery charger to tank. Insulate filler opening and uncertain a metal rod (mild steel) into solution ans connect positive clamp of charger to it. Switch on and leave overnight. Rust comes off tank onto metal rod. Plenty of stuff on YouTube.

[mikeybizzle]

Borrow a concrete mixer , fix the tank to piece of plywood , secure plywood to the concrete mixer drum , place some gravel in the tank , start the mixer and then go down the pub for a couple of hours . You will come back to some happy neighbours and a nice clean tank . Don't forget to coat the inside of the tank with something like " SLOSH " or similar that's up to the latest standards ( modern petrol turns some of the older sealants to jelly ).

[redbikejohn]

As you can see I could not do things like that with my moped so that is why I went for electrolysis. The tank on this was trashed inside. Jet washed it afterwards then used a homecmade soda blaster. Fitted inline filter just in case of bits.

[peterekins]

Get another tank, whatever you do will not be a great solution if its as bad as you say. (thumbs) I've tried both ways mentioned, they are ok for surface rust but any more and you lose the integrety of the tank.

[Wandering Star]

There is some solution available especially for classic bikes which seals the inside of the tank. Can't remember the name but I have seen it for sale at classic bike shows. Try googling petrol tank sealer and see what comes up.

[zimtim]

http://www.frost.co.uk/por15-stop-rust- ... black.html

used this stuff bit expensive but seems to of done the job. Buy more than you think you need as getting the sealant around tank can be a pain especially if like me the tank is something with odd shape XTZ 750. (thumbs)

[Kinioo]

I got it from them: http://www.ebay.co.uk/itm/Metal-Rescue- ... 51b58f5d67 ....amazing - bare metal ready to paint !!!

[davsato]

Never tried the electrolysis, looks handy for next time. I used a load of gravel and petrol and shook the hell out of it. Whatever you do seal the inside with Petseal or the rust will be back in no time, you can never get rid of it 100%