Fuel tank "red liner"

[ScruffyDroid]

Good morning

I've recently started a project on my Mono R100RT. It's been out of road use since COVID, started and warmed up regularly.

I notice the fuel tank had some very light rust and the red liner had started to come away.

I've degreased it with washing up liquid and No Nonsense Heavy Duty degreaser (as per Snowbum), rinsed extensively with clean water, and what seems like most of the red liner has washed through.

It's now full of 20% vinegar and 80 wood screws and being shaken about, a few times a day.

I've tried to see whether any common solvents dissolve flakes of liner - isopropyl alcohol, meths, acetone. Not a thing.

Has anyone got any suggestions to dissolve or remove the liner, since my concern is that when I use phosphoric acid (Milkstone remover), there will be remnants stuck to the tank, and flaky bits floating around.

Turning the tank upside down doesn't work terribly well, since the inverted lip is like a dam...

The plan is to strip and paint...

I was at the Airhead day at Sammy Miller's in the R65/2 outfit, if anyone else was there, but never asked anyone!

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[mikeyboy]

If you are repainting it any way,
Get it professionally dipped/acid dipped.
I use prostrip in Nottingham,but I bet there will be someone more local to you.

 

[oldenoughtoknowbetter]

If you are repainting it any way,
Get it professionally dipped/acid dipped.
I use prostrip in Nottingham,but I bet there will be someone more local to you.

Have recently done mine. White vinegar did the trick but needed to repeat process five or six times, using the same vinegar but strained between each application. I used an endoscope camera to check it had all gone and eventually it had. Took me around a fortnight to achieve that prior to treating any rust with phosphoric acid. If you rush the process it'll fail!

 

[PIGGLET]

As said above, if its being repainted, save a load of cocking about and get it acid dipped.

If you want to keep it original and just strip the red oxide lining i've used this method. Warning: you dont want to get any of this stuff in your eyes and if it gets on the exterior it will probably mark it so mask off the filler and top of the tank then cover the masking tape with duct tape.

Remove taps and strainers and fit rubber blanking washers to seal off the tap holes. I have annold set of taps to hold the washers in place.

Fill tank with caustic soda solution ( usually comes as granules to be added to water. Agitate take a few times a day for up to a fortnight to remove the red oxide. You may nees to drain and repeat to remove it all.

Next wash out and fill with hydrochloric acid (brick cleaner) agitate a few times a day until no rust and its all bright and shiny.

Next step needs doing in one go...

Drain out hcl and give very quick swill out with water, followed by warm air drying followed by fill with phoshoric acid. Swill the phosphoric acid round ro passivate the inside of the tank. It goes a dull grey colour. It should now look like a new tank with no rust or discoloration.
Tip out phos acid and give a rinse out with diesel. Tank is now cleaned and coated in corrosion inhibitor and if you have been carefull the original paint is preserved.
Its a right faff.
If you rush it you'll have to start again and the caustic and HCL are nasty. Tank cap used during the procesd will be scrap too.