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Stripping tank liner

Discussion in '"Stock" Alpine' started by Bill Blue, Nov 8, 2020.

  1. Bill Blue

    Bill Blue Platinum Level Sponsor

    Prepping a late series gas tank. It has been professionally stripped, but has a black residue that has resisted my efforts. I have soaked it with Strip Ease (three days), Methyl Ethyl Ketone and Acetone (24 hours). I have been agitating the solution with a length of chain that had been inserted. Dumped the witches brew. It contained small black gritty flakes. The liquid portion was yellowish. No sign the black stuff has been softened. I have considered the possibility the black stuff was blackened steel and not a coating. However, the black flakes point toward old coating. I successfully stripped a pair of tanks twenty years ago, but have no recollection of what I used.

    Any suggestions as to what will remove this stuff?

  2. sunalp

    sunalp Platinum Level Sponsor

    Most likely if you've used all that stuff in there, it's not coming out without
    cutting the tanks open to manually strip them ( with a grinder).
    You'd probably be able to coat over them as they don't seem to be coming off.
  3. Barry

    Barry Platinum Level Sponsor


    The company that sells POR-15 claims that POR-15 Strip Gel "quickly lifts the toughest automotive coatings from
    metal surfaces."

    The Safety Data Sheet shows that it is a mixture of:

    78-88% Dichloromethane (aka, methylene dichloride or methylene chloride)
    7 - 10% Methanol
    1 - 5% Toluene
    1 - 5% Ammonia​

    No idea if it would work for your situation and I would not try to home-mix that witches brew.
    Last edited: Nov 8, 2020
  4. Limey

    Limey Diamond Level Sponsor

    I reckon anything left is rock solid so perhaps a good layer of POR15 coating will lock down the solid stuff that is left. Shouldn't come off in your lifetime?
  5. DanR

    DanR Diamond Level Sponsor

    For the record, It was I that removed the dual tanks from an Alpine, then had the tank chem dipped like I do most of my metal parts. They were not treated in any way by me so I have no idea what the "black stuff: is.

    The Fuel tank (right hand) Bill has is a mate to the one I have in the shop and it has the same "black" stuff in the bottom.

    Bill and I discussed briefly what it was and what could be done to remove the black stuff.

    I found what looks like tiny, tiny, tiny particles that have a very shiny look and they crush easily. But there remains a hard residue on the metal.

    A solution is yet to be found other than to utilized POR15 Tank Sealer.
  6. Limey

    Limey Diamond Level Sponsor

    I have heard that some people burn of the residue from the outside with a suitable heat source
  7. DanR

    DanR Diamond Level Sponsor

    Never heard of the Gel... Thank Barry, I will look into that product as something I can use.
  8. Alpine 1789

    Alpine 1789 SAOCA President Platinum Level Sponsor

    I followed Jim E's advice years ago and used muriatic acid. Or, more accurately, used muriatic acid to remove what was left after I'd tried the more conventional methods. It is nasty stuff, but like Jim said, it left my SV tanks looking like they'd been bead blasted.

  9. DanR

    DanR Diamond Level Sponsor

    I have used it also, But do not recommend it unless you are extremely cautious and have absolute perfect ventilation.
  10. Alpine 1789

    Alpine 1789 SAOCA President Platinum Level Sponsor

    Amen on both points! I did it outside, with protective gear on. And was still very nervous the whole time.
  11. Aladin Sane

    Aladin Sane Gold Level Sponsor

    Ah you bunch of pansies. As a chemical engineer, a little hydrochloric acid is not something that scares me.
  12. DanR

    DanR Diamond Level Sponsor

    Yep! I think we ( Jim & I ) are pansies:)
    Alpine 1789 likes this.
  13. Bill Blue

    Bill Blue Platinum Level Sponsor

    Call me pansy #3. Its too hard to keep the tanks sealed during the process.

  14. sunalp

    sunalp Platinum Level Sponsor

    If you do use the acid, make sure you neutralize it . I've use it before and you have to rinse and use
    baking soda to stop the etching. Also, get them dry as soon as possible and coat them as they will
    rust up very quickly if you don't. I had one tank a few years ago that looked like new inside. I left it
    for a few hours and it looked like it had been sitting in a field for years . It was even more rusty than
    when I started!
    Last edited: Nov 10, 2020
  15. Bill Blue

    Bill Blue Platinum Level Sponsor

    Before I retired I was a state employee, working with metal finishers, regulating their discharge to city sewers. As a group, they hated hydrochloric acid for the reasons sunalp stated, plus the fact the vapors were very active. I had one company that had to replace their roof structure.

  16. Bill Blue

    Bill Blue Platinum Level Sponsor

    No luck finding a stripper that I feel is usable and capable of doing the job. Most seem to be gels or pastes. They all claim to do a fantastic job. None claim to be a "brush (or pour) it on and let it work" type of product. Sounds like the stuff I bought. Looks like I'm headed toward coating the black stuff.

  17. Limey

    Limey Diamond Level Sponsor

    Some Brit old timers may remember - In the UK we used to have some lovely stuff call Nitromors back in the day (Methylene chloride as a base but with other chemicals to penetrate the layers apparently). It's all Low VOC rubbish now but that stuff was goood. You new it was because your eyes watered as soon as you unscrewed the cap and it started to properly burn into your skin in about 5 secs. Was available straight off the shelf by the gallon. Good old days...
  18. Wayne67vert

    Wayne67vert Silver Level Sponsor

  19. hartmandm

    hartmandm Moderator Platinum Level Sponsor


    Have you tried brake fluid?

  20. Barry

    Barry Platinum Level Sponsor

    No offense, but it is widely accepted that chemical engineers are a half bubble off level. Probably related to studying P-chem.

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