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Thread: Cleaning copper gas tanks

  1. #1
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    Default Cleaning copper gas tanks

    I have two 80 year old copper gas tanks in a 1928 Elco. They carry around a significant amount of green sludge which inevitably gets stirred up in a seaway to the point where no amount of filtration can cope. Losing power under these conditions can exciting but is not highly recommended; consequently, I reflect on how I might clean these tanks without blowing up the boat and myself in the process.
    There appear to be inspection ports in each tank but with vertical baffles at regular spacings I cant imagine how it would be possible to extract all the crud from the bottom. On top of all this I can't help but wonder if the green sludge isn't some transmogrified copper compound which could mean the tank wall thickness is something less than it was in 1928. Does anyone know what this stuff is and how I might be able to remove it without killing myself?

  2. #2
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    Default Re: Cleaning copper gas tanks

    Quote Originally Posted by John Cowle View Post
    I have two 80 year old copper gas tanks in a 1928 Elco. They carry around a significant amount of green sludge which inevitably gets stirred up in a seaway to the point where no amount of filtration can cope. Losing power under these conditions can exciting but is not highly recommended; consequently, I reflect on how I might clean these tanks without blowing up the boat and myself in the process.
    There appear to be inspection ports in each tank but with vertical baffles at regular spacings I cant imagine how it would be possible to extract all the crud from the bottom. On top of all this I can't help but wonder if the green sludge isn't some transmogrified copper compound which could mean the tank wall thickness is something less than it was in 1928. Does anyone know what this stuff is and how I might be able to remove it without killing myself?

    We have an old copper gas tank as well, which has a cleanout fitting at the bottom. I drain this maybe once a year, and the tank stays quite clean and clear. I think you are dealing with the result of water at the bottom of the tank, corroding the copper. It could well be dangerous, if the corrosion has thinned the tank. The fuel pickup is usually above the bottom, to act as a preliminary water separator. This leaves the water. Without a cleanout drain, a pump with a stiff tube going to the low point may be an answer. Drigas, or similar also could help.

  3. #3
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    Default Re: Cleaning copper gas tanks

    Quote Originally Posted by John Cowle View Post
    I have two 80 year old copper gas tanks in a 1928 Elco. They carry around a significant amount of green sludge which inevitably gets stirred up in a seaway to the point where no amount of filtration can cope. Losing power under these conditions can exciting but is not highly recommended; consequently, I reflect on how I might clean these tanks without blowing up the boat and myself in the process.
    There appear to be inspection ports in each tank but with vertical baffles at regular spacings I cant imagine how it would be possible to extract all the crud from the bottom. On top of all this I can't help but wonder if the green sludge isn't some transmogrified copper compound which could mean the tank wall thickness is something less than it was in 1928. Does anyone know what this stuff is and how I might be able to remove it without killing myself?
    Bottom line, just get new tanks. Gas in the bilge can spoil your whole day.

    I went with a client to the San Juans on his '26 50+ foot Fellows and Stewart. We had trouble with crap in the gas. A manly Racor filter solved much of the problem. Added one of those little in-line filters and it improved things further. But it still had problems. We got to rock and rolling in the Straits and both engines went out. I drained a couple quarts of water out of the Racors and we were going again.

    But the engines would always suck up crap when you put the pedal to the metal.

    So, in my humble opinion, tanks are in order.

  4. #4
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    Default Re: Cleaning copper gas tanks

    Since you have clean out ports, the normal method of cleaning I use is steam cleaning as done by a marine service that specializes in that service.
    Jay

  5. #5
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    Default Re: Cleaning copper gas tanks

    If those tanks have a large enough inspection port, I'd remove the tanks from the boat, and steam clean the junk out of them. If that works well, and I see no reason why it would not, I'd then have the tanks Ultrasounded for metal thickness... It's quite possible that these tanks can end up being as good as new...

    Then... INSTALL a proper set of RACOR filters, in parallel so you can switch tanks easily...

    Then...KEEP THE FUEL CLEAN...and DRAIN the water from the bottom on a regular basis...

    Ohh.. one more thing, KEEP the TANKS FULL.. less condensation will occur and less water will end up in the bottom of the tanks...

  6. #6
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    Default Re: Cleaning copper gas tanks

    A quick thanks to all who have replied.
    Removal of the tanks would mean cutting open the roof and pulling the engines along with various bits. At that point I'd have to consider new tanks and re-powering with diesel even though I really like my old Chevy 292's. I think if I can find a safe way to empty and clean the tanks in place perhaps it would be possible to do a thickness and condition check at that time. I've not been able to find any "Marine Service" outfit in the this area with an appetite for messing around with old gas tanks. I suspect there are better ways to make a living.
    I do think water in the tank bottom is the likely diagnosis for the green stuff. In the meantime I will be in flat water for a while which should leave things relatively undisturbed as I ponder my options. Any further insights and suggestions will be appreciated.

  7. #7
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    Default Re: Cleaning copper gas tanks

    Usually bilge cleaning services also will steam out tanks. If there is a tank maker in your area, he may be able to direct you to a service.
    Jay

  8. #8
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    Default Re: Cleaning copper gas tanks

    There are certainly baffles inside the tank; I don't understand how steam cleaning is going to clean the 75%...66% whatever that lies beyond the baffles.

  9. #9
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    Default Re: Cleaning copper gas tanks

    Maybe there is a way to make some openings in the tanks and some bolt-down covers for the access holes. Are the tanks round or rectangular? Access openings could be made between the baffles, etc........just an idea. That may be a fairly labor intensive job, but so is removing all the equipment you mentioned.
    Steam cleaning is done by some radiator shops also, on auto fuel tanks.

  10. #10
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    Default Re: Cleaning copper gas tanks

    I had two tanks in Grantala that appeared to be the original 1938 tanks. They were plated brass by the look of them, riveted and with vertical baffles. Plenty of evidence of repairs. I didn't trust them - and that is with diesel, not petrol (gas if you prefer).

    When I removed the tanks - a difficult and very messy job, involving saws and air chisels, etc. they were full of mud at the bottom - at least a gallon of it in each tank. The crap had built up over 70 odd years - despite the tanks being fitted with drains. The tanks were a definite safety risk.

    I was rather glad to get them out of the boat.
    Carpe the living sh!t out of the Diem

    I'd rather look back at my life and say "I can't believe I did that" instead of being there saying "I wish I'd done that"

  11. #11
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    Default Re: Cleaning copper gas tanks

    Quote Originally Posted by pila View Post
    Maybe there is a way to make some openings in the tanks and some bolt-down covers for the access holes. Are the tanks round or rectangular? Access openings could be made between the baffles, etc........just an idea. That may be a fairly labor intensive job, but so is removing all the equipment you mentioned.
    Steam cleaning is done by some radiator shops also, on auto fuel tanks.
    They don't steam clean them, they submerge them in a caustic bath. Maybe steam cleaning is the final go-round, can't remember.

  12. #12

    Default Re: Cleaning copper gas tanks

    Hey John.... Good to see you posting.

    One thing to add... Zephyr is a FRESHWATER BOAT, so does not have the corrosion issues a salt water boat would have.

    JOHN POST A PICTURE.

    This boat is a beauty... with a lot of exceptional work done by John on many many parts of the boat.

  13. #13
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    Default Re: Cleaning copper gas tanks

    Thanks Peter.

    It's great having access to all these old boat wankers who are willing to take the time to respond. I'll try to post a photo as soon as I can figure out how to get the file size down to the legal limit for attachments.

    John

  14. #14
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    Default Re: Cleaning copper gas tanks

    OK Peter, I finally figured out how to compress and post a photo of Zephyr III although it seems kind of small and grainy. It was taken in the 1000 Islands 4 or 5 years ago so I'll try to post a few more recent shots when I get a chance to squeeze them down to a manageable size. How did you manage to post so many Dove photos?
    I'll also post some pics of what I think are cleanouts in the gas tanks and see if anybody can confirm if that's what they are.

    John
    Attached Images Attached Images

  15. #15

    Default Re: Cleaning copper gas tanks

    I use Photobucket and just paste the picture.... Nice picture..

  16. #16
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    Default Re: Cleaning copper gas tanks

    Other than mopping out what you can get to and having a good deal of business with safety clean Your going to have to remove the tanks.
    The dangers involved are immense and I would not even to begin to tackle cleaning without remote respirators and nitrogen pumped in to the tanks with lots of ventilation to keep the percentages down.

    Install lots of quality filter and change them regularly. Two banks and a couple of three way ball valves you can switch on the fly when things get iffy.

  17. #17
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    Default Re: Cleaning copper gas tanks

    Peter, I'll try Photobucket...I assume it can be found on line and downloaded.
    Tylerdurden, thanks for the thoughts. I like the filter and valve approach too... at least until I decide on something major like replacement.

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