Removing Rust from the inside of Fuel Tank Walkthrough

Discussion in 'Mechanics Garage' started by Diving Pete, Oct 9, 2016.

  1. Diving Pete

    Diving Pete Member

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    I have just restored my wifes rusty (on the inside) fuel tank on her CBR400 (NC29) & thought I would share a few lessons I learned on route:

    For light Rust
    Cider Vinegar (£11 for 5 litres) will do the job - you will still need to use the Bicarbonate of Soda to flush the ‘acid’ & it may take a few days for it to work..

    [​IMG]Vinegar by Pete Smith, on Flickr

    For Heavy Rust
    You will want to use Hydrochloric Acid.. - £26 for 5 litres.

    [​IMG]Acid by Pete Smith, on Flickr

    I followed the 2nd method.
    I decided to do this outside – the fumes from the acid are really toxic - & doing this inside REALLY IS CRAZY.
    Items required
    Rubber nitrile gloves, glasses, pump to suck out fluid, hose pipe, a stand for the tank, Hydrochloric Acid, bicarbonate of soda, Gaffer Tape (Duct tape), funnel & a couple of tools.

    [​IMG]Bicarb by Pete Smith, on Flickr



    First, empty the tank completely – use the pump to suck out the dregs of fuel, then remove the fuel tank filler cap & fuel tap.
    Block the fuel tap hole (zip tie a hose on it with a bolt on the other end).

    WEAR THE PROTECTIVE GEAR FROM THIS POINT

    [​IMG]Stand by Pete Smith, on Flickr

    Pour 4 litres of warm tap water into the tank then add 1 litre of acid (it really doesn’t need to be exact measurements) - Be really careful not to inhale the fumes & then cover the filler hole – stops getting acid splashed when you agitate the tank & also stops the fumes - I used the duct tape – but an emergency plastic filler cap would do a better job.
    Slosh the tank around every couple of minutes – I checked every 5 mins & had to replace the duct tape each time as it partially melts - lol.
    After just 20 minutes the acid had done its magic & the rust had gone from the tank – it ends up as sludge in the bottom of the tank, so I emptied the acid into the container & sucked out the rest using the pump.
    Now onto neutralising the acid.
    1. Fit the plug back onto the fuel tap.
    2. Fill the tank with water from the hose & then drain.
    3. Add ½ cupful of bicarbonate of soda to 4 litres of ‘warm’ tap water (from the hot tap – NOT BOILING WATER FROM THE KETTLE) in a container, give it a good shake / stir to mix it & then empty it into the tank. Seal the filler, give it a really good shake, then gently agitate the tank for a couple of minutes, & then drain it.
    4. Fill the tank with water from the hose & then drain.
    5. Add ½ cupful of bicarbonate of soda to 4 litres of ‘warm’ tap water (from the hot tap – NOT BOILING WATER FROM THE KETTLE) in a container, give it a good shake / stir to mix it & then empty it into the tank. Seal the filler, give it a really good shake, then gently agitate the tank for a couple of minutes, & then drain it.
    6. Fill the tank with water from the hose & then drain.
    7. Now totally drain the tank to remove any water from inside – I used compressed air & the pump to drain it, then refit the fuel tap & filler cap.

    [​IMG]Inside tank by Pete Smith, on Flickr

    All done Then completely fill it up with fuel. - This is not a 10 minute job. – lol
     
  2. A.M

    A.M Moderator Staff Member

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    Nice! I bet your wife is pleased!! :)
    Awesome of you to take the time to write up the details for here as well! Thanks!
     
  3. VFR4Lee

    VFR4Lee Member

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    No coating for the inside?
     
  4. Diving Pete

    Diving Pete Member

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    Hadn't decided on a coating as yet - it never had one before and I'm going to try putting 2 x capfulls of 2 stroke oil in a full tank over winter.
     
  5. Badbilly

    Badbilly Official VFRWorld Troll Of The Year!

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    Kind of extravagant to use organic cider vinegar. Hope you had some left over for salad dressing. ;)

    To hasten removal of surface rust, use of ball bearings or marbles are sometimes employed.

    Here, a 10% solution of HCl can be found in the big box stores as Muriatic Acid.

    Another acid neutralizer is 5-7% household bleach diluted 100%. Any of these method work but need to be flushed with water between apps. A pinch of bicarb in a measure of vinegar is good evidence.

    Coat that tank.. once steel oxidizes it never stops. The oil will retard it somewhat but if coating is in the future, the oil will have to be removed completely for the coating to adhere.

    Someday using Yamahas patented vacuum forming process we may see a rise in aluminum tanks. Had a "breadloaf" on a racebike way back and Heinrich manufactured some large capacity tanks for BMWs that were superb.
     
  6. Diving Pete

    Diving Pete Member

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    I did - lol - at least a litre left...

    For coating the inside I need to look at some products as I haven't seen any yet - was more concerned with fixing the rust first.
     
  7. Badbilly

    Badbilly Official VFRWorld Troll Of The Year!

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    Enough for some pickled beets or as you folks call them beetroots.. LOL

    Any of the UK bike aftermarket suppliers should have coating kits.

    Here in the land of slick advertising we now have not only cider vinegar, but cider "flavored" vinegar. Labeled for sure but in small print..
     
  8. Jeff_Barrett

    Jeff_Barrett Member

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    Apple Cider Vinegar works great ... I'm etching and lining the VF1000F tank on the project bike I'm working on now.

    I just bit the bullet and bought a Kreem kit. Lolz!!
     
  9. VFR4Lee

    VFR4Lee Member

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    I hear of something called Caswell coating for plastic tanked aprilias.
    But, that's very different then. Nevermind.
     
  10. Diving Pete

    Diving Pete Member

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  11. Badbilly

    Badbilly Official VFRWorld Troll Of The Year!

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    Now I'm wondering in that product line if the tank sealing preparation is compatible with the rust converter. Similar rust converter products here work really well as a base for repaints on surfaces like wrought iron.
     
  12. Badbilly

    Badbilly Official VFRWorld Troll Of The Year!

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    In a recent study it was found that rice vinegar was good for removing rust from Japanese tanks.
     
    Glenngt750 likes this.
  13. VFR4Lee

    VFR4Lee Member

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    No good for that American rust though, LOL.
     
  14. Badbilly

    Badbilly Official VFRWorld Troll Of The Year!

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    Household distilled vinegar at +/- 5% can be left in a steel bike tank for some time as long as it's toppep up. Same thing for resurrecting cast iron cookware that has see better days. Various dilute mixtures of HCl should not be left for various reasons.

    Tanks that are starting to rust from Ducati and MotoGuzzi prefer aged Balsamic as the vinegar of choice.
     
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