Fount layer?

Discussion in 'Fettling Forum' started by Scott D, Feb 15, 2021.

  1. Scott D

    Scott D United Kingdom Subscriber

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    C8E16A57-DDF4-4E91-BD61-81A6AC015E7E.jpeg D40FC770-4DFF-4183-B9A0-5B0B637F8193.jpeg 8EB72C73-C612-4044-B7C9-2DA3EB5F0B54.jpeg I am part way through the strip down of the MEWA 351 I bought a month or so ago. The steel fount seems to be in good condition but when I shone a light inside it has what looks to be a layer of waxy grey material. It looks very uniform in colour and appearance except for the very centre where there is a hole in the grey layer down to what looks like metal. The hole indicates the grey layer is perhaps a millimetre thick. Am I likely looking at fuel residue or some kind of tank seal treatment, Caswell etc? Sorry the picture isn’t great, best iPhone shot I could manage! Trying to figure out if I need to clean it, or be worried about a hole in the caswell, or just that it might have needed Caswell in the first place. Or would an application of Caswell just be a precaution for a steel tank? I’ve not pressure tested yet, only just sorted the NRV tonight.

    Thank you
     
    Last edited: Feb 15, 2021
  2. Fireexit1

    Fireexit1 United Kingdom Subscriber

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    Hi Scott - I do not know if they were coated inside at the factory as Coleman still do. If it is a stubborn fuel residue that will not respond to distillates or hot soapy water, my "next step" is a strong solution of caustic soda. But watch the heat generation and take precautions as it can get lively in there !
     
  3. podbros

    podbros United Kingdom Subscriber

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    Have you scraped a bit out to have a look at it?... See if it burns or watch what it does in a blow torch flame?
     
  4. Scott D

    Scott D United Kingdom Subscriber

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    I tried to loosen a bit with an o ring pick but it seems fairly stubborn so thought I’d ask before pulling chunks out of it. Those are the marks you can see around the hole, they aren’t cracks.
     
  5. podbros

    podbros United Kingdom Subscriber

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    I've never used a tank sealer, so can't help with comparisons.. When you said waxy I thought it would be possible to move it more easily..

    I would determine the fuel used then tie a piece of white cotton on a thin piece of dowel or similar.. dunk it in the fuel and rub it on this stuff to see if any comes away?
     
  6. Scott D

    Scott D United Kingdom Subscriber

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    Ah, looks waxy but it’s not for coming off. The seller reckoned it was a runner. I just want to be sure of what I’m dealing with. I’ll have another poke at it tonight.
     
  7. Henry Plews

    Henry Plews Subscriber

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    The amount of light, camera angle etc. may not be giving a true representation of what you're looking at.

    Are you sure the lining isn't just tinning ? Is the mark directly below the central bung ? Is there a wire gauze filter sticking out of the fuel pickup tube which could have scratched the surface ?
     
  8. MYN

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    Pour in some lacquer thinner or acetone and let it soak a little while. If any of it comes off, you'd need to remove all of the layer.
    If it remains intact, just leave it alone and proceed with the rest of the fettle.
     
  9. Tony Press

    Tony Press Australia Subscriber

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    My advice would be to leave it alone unless you are sure what it is. If it does not forms a residue or go sludgy when you put fuel in it, leave it.

    Clean your fuel tank by rinsing it with kerosene until no residue appears in the rinse; then fill the tank with its normal fuel and leave it sit for a couple of days. Shake the tank, empty the fuel and see if it’s clean.

    What you don’t want to do is chemically remove a proprietary coating unless you have to.

    Cheers

    Tony
     
  10. Scott D

    Scott D United Kingdom Subscriber

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    Thank you all, I will start with a fuel soak and rinse of the font and see how it goes.
     

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