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  • Cast Iron

    I have a water pump for a ranch irrigation system that froze and cracked. I want to try and weld it up rather than replace it (Its my dads) I dont have any experience with cast iron so what process and method do you suggest. Cracks about 6 inches long and the castings about 3/16 - 1/4 inch thick. I have Mig, Tig and Oxy-Acet. Thanks - Mark

  • #2
    Grind the metal along the crack and clean it out the best you can. Drill a small diameter hole at the ends of the crack so it won't spread. Preheat the piece and braze the crack with you O/A.

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    • #3
      Originally posted by TJJ
      Grind the metal along the crack and clean it out the best you can. Drill a small diameter hole at the ends of the crack so it won't spread. Preheat the piece and braze the crack with you O/A.
      Is the backside machined for something or does it matter what the backside penetration ends up with? If the backside dimension is critical you might want to put a scab patch over it. I'd go with brazing either way since you don't have much experience.
      Two turn tables and a microphone.

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      • #4
        Re:

        pay and experienced guy in cast, its tricky, and most dont know the correct way to do it.

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        • #5
          that's thick enough cast to get the job done fairly easy in my opinion. i use oa for cast, in fact that's the only reason i have oa. preheat the area around the peice untill it gets just about glowing hot, then puddle on the crack and fill with cast filler rod. do it in three parts- go two inches, pound the everliving crap out of the weld with a ball pean hammer, than go to the next few inches. when it gets done and you've beaten the snot out of the last section, pour sand over the entire peice and let it cool slowly.
          i hate working on cast and i'm not a fan of oa, which i'm scared ****less of, but sometimes you have to do what you have to do. some people say they use nirod with the tig process on cast, but i don't get great results that way.

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          • #6
            I welded cast to flat bar and it worked ok ( I just didn't know it was hard to do, so I did it) I have a miller 90 Amp mig machine, using .30 flux core wire. I used the lowest setting, and welded it quickly to keep from eating up the cast. both supports have held up a 40 lbs bird, with no problem,, see below... I guess ignorance is bliss..
            Jim Young
            www.jimyo.com

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            • #7
              Originally posted by stang
              pay and experienced guy in cast, its tricky, and most dont know the correct way to do it.
              I do just fine with some cast ... but when it really matters ...I have the pro across town do it ...does an awsome job every time...for a desent price...

              having said that the burden is on you to desribe the result you're after..

              i.e. bearing bores alignment , build-up restictions etc.


              I won't give work to a pro who " already knows what I need " and shirks off my input no matter how good his skills are...
              sigpicViceGrip
              Negative people have a problem for every solution

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              • #8
                freeze distortion

                Welding aside ...the tremendice force of water expanding @ freezing point

                not only cracks iron ....but often actually streches the iron in some cases where wall thickness is very uniform in the crack area....

                it is some times necessary to reshape the area, or even trim the two sides of the crack significantly....if mating parts or surfaces will ever be expected to work out again...

                best to you..
                sigpicViceGrip
                Negative people have a problem for every solution

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                • #9
                  I had this same job on a pump case and fixed it sucsesfully with stick. I don't know if your tig will weld stick but here is how I did it. First thing I did was build a ring of bricks to set it in and put sand in the bottom. Then I heated it up uniformly to where it sizzled spit off instantly, (was shooting for 400 degrees) then instead of grinding the crack out because grinding discs leave trash in the metal that will cause problems welding (pin holes) I used 7018 1/8th rod and lots of heat I cant remember how much but I gouged out the crack trying to get at least 75% through the metal. This worked best going vertical down and with extreme leading angle you gouged into the crack and kind of spooned it out. You have to have it hot enough and go fast enough that you don't lay down metal. It's really not as hard as it sounds. Clean it up with a chipping hammer. no grinding. Now its time to reheat the piece. You will need nickel rod to weld the crack and it runs similar to 7018 heat settings. Weld a few inches and then peen it with a hammer good and continue until you finish and then peen it all good. Reheat it back to good and hot and cover it with sand and let it cool over night. The keys are keeping it hot, peening it and no grinding. Later I found out a die grinder with a carbide burr would have worked much easier to groove it out. If you decide to braze it use a carbide tool also to grind it.

                  Good luck

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                  • #10
                    Originally posted by moosedog
                    I had this same job on a pump case and fixed it sucsesfully with stick. I don't know if your tig will weld stick but here is how I did it. First thing I did was build a ring of bricks to set it in and put sand in the bottom. Then I heated it up uniformly to where it sizzled spit off instantly, (was shooting for 400 degrees) then instead of grinding the crack out because grinding discs leave trash in the metal that will cause problems welding (pin holes) I used 7018 1/8th rod and lots of heat I cant remember how much but I gouged out the crack trying to get at least 75% through the metal. This worked best going vertical down and with extreme leading angle you gouged into the crack and kind of spooned it out. You have to have it hot enough and go fast enough that you don't lay down metal. It's really not as hard as it sounds. Clean it up with a chipping hammer. no grinding. Now its time to reheat the piece. You will need nickel rod to weld the crack and it runs similar to 7018 heat settings. Weld a few inches and then peen it with a hammer good and continue until you finish and then peen it all good. Reheat it back to good and hot and cover it with sand and let it cool over night. The keys are keeping it hot, peening it and no grinding. Later I found out a die grinder with a carbide burr would have worked much easier to groove it out. If you decide to braze it use a carbide tool also to grind it.

                    Good luck
                    Man this IS impressive I will try it next time I get a devistation where lots of body fluids and what not are infecting the crack ...further I finally found a large needle-peener at an estate sale last year came with heavy and fine needle heads....

                    results are awsome and FASTER than John Henry....

                    don't know if a cheap H.F. unit would work as well or not
                    sigpicViceGrip
                    Negative people have a problem for every solution

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                    • #11
                      Cast Iron

                      I haven't tried it but Muggyweld.com sells stick rods that are suppose to work well.
                      HH135
                      Victor 310, J-28 Torch Setup
                      Thermal Arc 190S
                      Thermal Dynamics Cutmaster 51 Plasma
                      Andy's Place

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                      • #12
                        re:

                        Originally posted by abooker
                        I haven't tried it but Muggyweld.com sells stick rods that are suppose to work well.
                        ------- nickel rod , and sometimes stainless can be used, no matter what off brand calls thier rods. those numbers are thier made up part numbers ,
                        nickel 99 widely used for "junk cast" , with little iron in it , thus 99% nickel,
                        nickel 55 widely used for cast iron 55% nickel, less nickel to weld with the iron in the cast iron,
                        and many other combinations and percentages of nickel, if you know what your welding on, in which i have found most dont,
                        * stainless is sometimes used,
                        muddy water unless ya know what your doing, the preheat and cool down has to be just right, as was posted by others, i wouldnt wanna try it, lol

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                        • #13
                          a few weeks ago i repaired one of my cast vises and i have put it through the mill since and it works great, no break yet i beveled the edges of the broken pieces with a die grinder preheat to 700 deg (checked using IR gun) welded it using 3/32" ni55 at 80 amps 3 passes 1" beads, peen the bead then another 1" bead then peen etc. till filled then post heated to 700 deg then threw it in the coals in my shop stove and let it cool as the coals died out about 5 hrs.
                          tc.....jim

                          miller bobcat 225
                          miller AEAD200LE with hf tig
                          mm175, mm252 w/30a
                          lincoln PT 225, mm211, TA181i
                          stickmate LX 235/160
                          Speedglas 9100X/9100XX/Miller DE
                          hypertherm 380
                          TD cutmaster 52
                          steel max 14" & evolution 7.5" dry cut saws
                          2 victor journeyman/3 superange, smith little, meco midget torches
                          ridgid chop saw
                          kalamazoo band saw/ 8-4.5" & 1 rockwell 9" grinder
                          case 580 backhoe for things i can't lift

                          if at first you don't succeed
                          trash the b#####d (me )

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                          • #14
                            Forgive my ignorance, but what does the peening do?
                            Thermal Arc 185

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                            • #15
                              peening and the preheat and postheat are all methods used to relieve stresses in the metal that is caused by the expansion and contraction of the heated areas affected by the weldiing temps needed for proper fusion and the metalurgical changes brought on by heat to the metal
                              MILLER 300 DEISEL
                              MILLER 2050 PLASMA
                              MILLER DYNASTY 200DX
                              RYOBI CHOPSAW
                              ANGLE AND BEVERLY SHEAR
                              MILLER 250HF
                              MILLER REGENCY 250 SPOOLMATIC GUN
                              S22P12
                              LN25
                              SAE400 DEISEL
                              2 WELDING TRUCKS AND OTHER STUFF

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