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Thread: Removing glass from bronze ports

  1. #1
    Join Date
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    Default Removing glass from bronze ports

    I have a couple of opening bronze ports with cracked glass. The glass is held in by a threaded ring. Anyone know how to remove these, seized with corrosion?

  2. #2
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    Walney, near Cumbria UK
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    Default Re: Removing glass from bronze ports

    Gentle heat and WD40?
    If you break out the glass you can soak both ends of the threads.
    It really is quite difficult to build an ugly wooden boat.

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  3. #3
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    Default Re: Removing glass from bronze ports

    Any tiny holes or notches that would be used to unscrew them? If the glass is trash anyway I don't see why a gentle bit of heat could harm the metal to soften the rubber / sealing compound. I had some old ones that had a pink powdery stuff inside between the 2 bronze plates. Wear a respirator if heating them, could be any old nasty stuff.

  4. #4
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    Default Re: Removing glass from bronze ports

    The stuff you want to use is "Kroil"; a web search will turn up a source for you. It's not only the best break-free goo out there, it's the only break-free goo that I've found to work on bronze/copper alloys --my boss at PT Foundry put me onto the stuff years ago and I've never looked back. It's simply amazing what I've gotten un-frozen with the stuff.

    Pour on the Kroil and let it soak for a couple days. A couple times a day, tap them with a hammer, to help open fissures in the corrosion for the Kroil to penetrate. After a couple days, play a gentle drum solo on the fittings with a light hammer, to fracture out corrosion, and have a go at winkling out those retaining rings. If they don't move, give them a gentle heating with a torch, another drum solo, and have another go. If they still don't move, repeat the entire multi-day soak/tap/heat process. It can be a long process, freeing frozen threads. Be patient.

    Alex

  5. #5
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    Default Re: Removing glass from bronze ports

    Quote Originally Posted by lupussonic View Post
    Any tiny holes or notches that would be used to unscrew them? If the glass is trash anyway I don't see why a gentle bit of heat could harm the metal to soften the rubber / sealing compound. I had some old ones that had a pink powdery stuff inside between the 2 bronze plates. Wear a respirator if heating them, could be any old nasty stuff.
    There are notches, but they are too stuck. Heat might be a possible solution.

  6. #6
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    Default Re: Removing glass from bronze ports

    You could always drill small holes or grind small notches in to one plate and with the other held fast, you can get some torque going... like 2-3mm, and you'll be the only one to notice. The nest person will thank you. In my world, stuff has to be get-at-able.

    Edit: cross post.

    Make a big ass spanner, so lots leverage for the notches. A little heat as well and I'm sure they'll give.

  7. #7
    Join Date
    Oct 2018
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    lagunitas, ca, usa
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    Default Re: Removing glass from bronze ports

    Since the glass is already broken and you're replacing it, if you break it entirely and dig out the shards between the ring and the base casting, then you will remove some pressure against the threads and it should get a little easier. Plus the cavity makes a good place to fill with some sort of oil/kroil/wd-40 (wd would be my last choice, it doesn't work that good. Straight diesel oil is good in a pinch.)

  8. #8
    Join Date
    Jul 2011
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    Lindstrom, MN
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    Default Re: Removing glass from bronze ports

    Kroil sounds good. You might also try soaking in dilute hydrochloric acid, EDTA or Calgon to dissolve the corrosion. Muriatic acid runs around 40% in the hardware store, so dilute it 3 parts water to one part HCl. Pour the acid into the water, not vice versa.

    Copper forms basic copper chloride in marine environments. Something that will dissolve this corrosion product might be worth a try. Wikipedia says that mineral acid, sodium hydroxide and chelating agents such as EDTA and Calgon will dissolve it.

    Conservation of Marine Archaeological Objects says that Calgon or EDTA dissolve this type of concretion. Scroll up to page 239 where it tells you how to clean silver coin lumps with various solutions of HCL, Citric acid, EDTA or Calgon.

    EDIT: If you can't get a grip on the ring, maybe you could epoxy something to the glass and turn it with that. It might help get the ring moving. The more surface area glued the better.
    Last edited by MN Dave; 10-30-2018 at 10:24 PM.
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  9. #9
    Join Date
    Apr 2000
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    Southampton Ont. Canada
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    Default Re: Removing glass from bronze ports

    I would make a spanner/wrench, like lupossonic said.
    Some short bits of flat bar the same size as the notches, welded to a longer handle.
    R
    Sleep with one eye open.

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