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Thread: Cast Iron (repair)

  1. #11
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    Jan 2017
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    "Super rare device." A weld joint would spoil the appearance, braze is better, near invisible.

    Re pinning & epoxy: how would one drill the 2 pieces to get holes lined up exactly?

  2. #12
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    Quote Originally Posted by Bob Engelhardt View Post
    "Super rare device." A weld joint would spoil the appearance, braze is better, near invisible.

    Re pinning & epoxy: how would one drill the 2 pieces to get holes lined up exactly?
    I would use something like transfer screws to locate the holes between parts. Could have something like a pin with threads on one end, threaded into one part. Locate and drill corresponding holes in the other part. Then stick the parts together with loctite in the holes.

  3. #13
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    pin and epoxy as suggested PLUS a scab plate hidden on the bottom. That is how i would proceed.

    Scab plate on top as well would be better yet but spoil the appearance.

  4. #14
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    Quote Originally Posted by wierdscience View Post
    O/A Torch and braze it.Brass will be every bit as strong as the oringinal cast iron and with proper fixturing very little if any warpage will occur.It's my go to for repairs that need to stay straight and machinable are needed.
    +1 for this.
    I have done it severL times with excellent results. Almost invisible.
    I cut it off twice and it's still too short!

  5. #15

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    Cast iron welding is a terrible idea to me. I was once working on a broken casting for a professor in my high school machine shop class, a broken foot for a dividing head. I made a new piece, the welding class nickel rodded it back on, and I machined it back. I burnt up two Chinese HSS endmills just getting the job done cutting through the nickel. I came back the next day and the casting had cracked just from the built up stresses. That's anicdotal, and I don't think the students or professor preheated it right. Then again it was a precision part that you wouldn't want to warp. I do think welding has it place, especially for items that go through large heat cycles (like engine components), just not here.

    I've seen a lot of brazed repairs that have been in service longer than the unbroken tool. I am very comfortable with a proper braze repair, it's nearly if not as strong as the cast. Be it TIG or OA, that's the way to go for general structural repairs. In your case it looks like a great job for a classic OA repair.
    Last edited by The Metal Butcher; 05-15-2019 at 01:44 PM.

  6. #16
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    I dont recommend the glue for that.

    I have brazed a lot of CI and it is the preferred method for an item like that.

    I have also used the TIG method with silicon bronze filler and that is my go to when I need strength and cant fully heat the parts. You do need some preheat either way.

    Neat looking item!! JR
    My old yahoo group. Bridgeport Mill Group

    https://groups.yahoo.com/neo/groups/...port_mill/info

  7. #17
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    Quote Originally Posted by Bob Engelhardt View Post
    Re pinning & epoxy: how would one drill the 2 pieces to get holes lined up exactly?
    You drill oversized holes (you need slop so you can align the parts) as close as you can then fill the holes with what ever epoxy product you chose

    shove in the pins on one side. The pins should have grooves on them or use threaded rod or screws to grab the epoxy.

    shove other side on to the pins and line up the two pieces until they dry.

    You can put a thin layer of epoxy in between the two sides, it may add strength and will fill any small holes

    wipe it clean before it drys and paint.

    Should be almost invisible.

    P.S. brazing cast iron isn't hard but it can be exasperating at times, heat is everything. It is much less likely to cause warping or cracking in the base metal then welding.
    The shortest distance between two points is a circle of infinite diameter.

    Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

  8. #18
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    Oct 2002
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    I know a guy whose moniker is Cast Iron Mike. His shop is in Marysville, Washington. Business name is Cast Iron Repair. He has welded cast iron professionally since the early '70s. Man, he is a whiz! People ship him stuff from all over the country for repair. If it were up to me we'd award guys like this a Presidential Lifetime Achievement Award or something.

    Mike is in his '80s, still works every day. I asked him if he wanted to train an apprentice to carry on after he's gone and he said, "Maybe someday!"

    Cast Iron Repair
    16129 Smokey Point Blvd
    Marysville, WA 98271

    No website, no email. But if you take a few pictures of your leg with some dimensions and mail them to him, he might be able to quote you without you having to ship it there.

    Really my tip-top very best recommendation. Forget epoxy, brazing, or stick welding, not if it matters.

    metalmagpie

  9. #19
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    Jul 2017
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    Buffalo NY USA
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    There's also metal stitching. Link to wiki description https://en.wikipedia.org/wiki/Metal_stitching

    I've seen the results of this kind of work, and its amazing. There is a local shop that does this kind of thing on large industrial castings. Done right, the repair is almost invisible, and actually stronger than the parent metal.

  10. #20
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    How much gap is needed for braze to flow into? I have clean break bit of cast iron that fits back together nicely. If I grind off a bit to make a gap it will need a special jig to align it. The break is through a bolt hole which ideally stays the same size.

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