Can you weld/braze cast iron?
#1
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Join Date: Jan 2015
Location: USA
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Can you weld/braze cast iron?
I am needing to replace my pressure regulator for my well pump, but I'm having trouble getting a parts supplier to decide whether they have the part or not (the website and representative says it's in stock, but it hasn't shipped after 6 weeks). The pump and regulator are cast iron and the regulator's 1" nipple that connects to the discharge port of the pump broke off when attempting to remove the regulator.
I've got the regulator in the electrolysis bucket to remove the rust the same way I did for the undamaged part of the regulator (pictured.)
Can I just buy a short black iron pipe nipple and bring it and the cast iron regulator to a welder? (I don't think I have to be concerned over a few inches of black iron pipe with potable water when the internals of the pump has no rust protection either)
I've got the regulator in the electrolysis bucket to remove the rust the same way I did for the undamaged part of the regulator (pictured.)
Can I just buy a short black iron pipe nipple and bring it and the cast iron regulator to a welder? (I don't think I have to be concerned over a few inches of black iron pipe with potable water when the internals of the pump has no rust protection either)

#3
I think a professional welder will be able to do it no problem. They do it often and know what works best. Looks like your bucket cleans the parts up nicely... they will appreciate that.

#5
Most places will probably tell you they can't guarantee how long the repair will last. Like Mark said it's kind of a crap shoot. My grandpa always brazed cast. But he was old school.
#6
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I have welded cast iron three times, the last two times successfully, although I still think that I would take it to the local welding shop the next time, the first time not so successful, but nevertheless a bit exhilarating and comical. It was a block from an old John Deere two banger, and I had a good lead on a replacement, so a little room for error, and was young, so gave it a try. My dad who was a millwright and my uncle who was a welder by trade were my coaches. I packed the block with sand in a wheelbarrow, kept preheating with a torch, did just a little at a time, brought it down slowly with the aid of a torch, put a welding blanket over it, and it really was a thing of beauty. An hour or so later, standing around with a beer, I was beaming as my dad told me that he thought I might have done it. All of a sudden there was a bang, sounded about like a 12 gauge had gone off, my dad looked, at me, shrugged a little, and said "nope". Sure enough, there was a crack right down the middle of my beautiful weld. I tried brazing it later but couldn't seal the leak, so ended up replacing it.
#7
Group Moderator
Cast can be welded but as you have seen in this thread, it takes a skilled welder to do so. My only advise for you in addition to what others have said is, make SURE you get someone who is experienced in welding cast. Just because you ask him if he can weld cast & he says yes, doesn't mean he is good at it. Ask around & find someone who REALLY IS experienced in this or you may end up wasting your time & possibly loosing some money in the process.
I can fix some cars, but that dont mean I can fix YOUR car.
I can fix some cars, but that dont mean I can fix YOUR car.
#8
Member
I've successfully welded cast iron many times. Unless you're a skilled welder, take it to a pro. It needs to be pre heated and a high nickel rod used, but it's really not difficult. I've also repaired cracked cast iron with a really good epoxy.
#9
Member
Oh yeah, minimac mentioned nickel rod, and caused me to remember that I paid right around $50 for 5 lbs. when I bought it for that tractor block, and that was about 40 years ago. So between that and the added the added gas and time to preheat the iron and so on just saying they're probably not dinging you if they want a bit extra for that job. Still worth it I'm sure since that sounds like your best solution.