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Fragile Cast Iron

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  • Fragile Cast Iron

    My wife wants me to make a "Water Feature" for her using an antique cast iron pot which has an approximate 6" crack from the rim downward as shown by the attached photos.

    The old pot is thinner than you might expect - 1/8" at the lip enlarging to 3/16 - 1/8 going downward. It is very old even for an old cast iron pot and I suspect it has become significantly thinner at the rim over the years from rust resulting from laying rim down in the ground. Also, the iron is very poor quality.

    I'm not sure, but I think the crack has lengthened a couple of inches just from the handling involved in hauling it 70 miles from her mother's farm to Little Rock.

    I need to repair the crack only to the extent that it holds water while remaining stationary with the repair being as unnoticeable as possible.

    I have TIG, MIG, FCAW, and O/A capability but I'm afraid of putting localized heat on the pot.

    My ideas are as follows:

    1) Drill a small hole at the end of the crack and bevel and clean the crack with a die grinder no matter which method is chosen.
    2) Heat the entire pot and stick weld with 3/32 cast iron rod.
    3) Braze it.
    4) My Front Runner: J.B. Weld.

    My best results with cast have been with brazing. I have had no experience with modern FCAW rods. I welded (or attempted to weld) a lot of cast 45 or so years ago as a kid growing up on a cotton farm but this is my first involvement with it since I resumed welding as a hobby after I retired.

    Any suggestions would be appreciated.
    Attached Files

  • #2
    Braze it if not worried about a color match. I would mig it with cast iron wire only because i stock it and have had perfect results with it...Bob
    Bob Wright

    Spool Gun conversion. How To Do It. Below.


    • #3
      Cast iron is finicky
      You absolutely must follow the recommended procedures or you end up with junk
      I tried f-Ing around with some, trying the "easy way out" ... And it wasn't
      Furthermore, if you've not welded in a while, it is even harder

      Go with JB Weld



      • #4
        I would not put any heat to it. JB weld or some sort of epoxy I guess. Any way to make a liner for it instead of trying to repair? Maybe some pond liner material?
        Trailblazer 250g
        22a feeder
        Lincoln ac/dc 225
        Victor O/A
        MM200 black face
        Whitney 30 ton hydraulic punch
        Lown 1/8x 36" power roller
        Arco roto-phase model M
        Vectrax 7x12 band saw
        Miller spectrum 875
        30a spoolgun w/wc-24
        Syncrowave 250


        • #5
          Fragile Cast Iron

          I've had good success using NiRod & Tig.
          I just use a 3/32 rod, remove all flux & scotch bright clean. Warm complete pot to 300 deg. Then Tig weld with just enough heat to knit weld in. I weld about 3/4-1" then lightly peen weld. I'd probably start on open end & back weld. Post heat even keeping to 300 deg. Then wrap in fiberglass insulation let cool overnight.


          • #6
            If your just using it for a water feature why not take it to a spray on Bedliner place tape off the outside and have them spray the inside? Waterproof, the inside will be black, don't have to attempt to weld the crack.
            Miller syncrowave 200 runner with coolmate 4
            and wp2025 weldcraft torch
            Miller 125c plasma cutter


            • #7
              Fragile Cast Iron

              Thanks for the really good suggestions.

              The wife wants it painted black, so I've decided to avoid the crack problem and permanently paint it black by going with the RhinoLiner both inside and outside.

              Great idea, jrsgcsr - thanks.


              • #8
                Originally posted by dkennett View Post
                Thanks for the really good suggestions.

                The wife wants it painted black, so I've decided to avoid the crack problem and permanently paint it black by going with the RhinoLiner both inside and outside.
                I used something similar to coat the fender deck on my 35 yr old lawn tractor. (Bondo paint on bed liner - got a real deal thru work.) Here's a photo taken right after the maiden voyage of the boom sprayer. I tossed the mount together out of stuff laying about. I also put the bedliner on the inside of a wheel barrow and a lawn/garden utility trailer. Better planning on my part would have allowed me to use the rest instead of tossing it.
                Attached Files

                Many cordless tools...........
                2 cordless hammers
                2 cordless punches
                1 cordless chisel
                2 cordless screwdrivers, 1 + and 1 -
                and a cordless adjustable wrench that also doubles as a hammer.....


                • #9
                  Fragile Cast Iron

                  Look up ChuckE2009 on YouTube. He does some beginner cast iron vids that would be right up your alley.


                  • #10
                    that stuff on tv, fix a leak in a can, that pot being round may give ya grief if any amount of heat is applied, weelding may be iffy at the least, unless you had an industrial oven and got to almost red then weld it and peen every inch or so


                    • #11
                      Fragile Cast Iron

                      Somewhat off topic, related to the truck bed liner being discussed, several years ago the stock black painted front bumper on my Landcruiser was badly scratched up.
                      I had it sprayed with RhynoLiner & no more scratches for the next five or so years until I traded it @ 375,000 miles.
                      It's some tough stuff.