Welding Cast Iron

One-match fire

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Over the past several years, I have been fortunate to be able to break some cast iron parts for things I was moving from where they were to my shop where they are now.
I was told that the only good way to weld these parts back together was TiG. Does anyone have anything GOOD to say about this? I would really like to get these parts repaired.

Two of the parts involve a large hand-spinner for collecting honey. The spinner fell while in transit and broke not only the handle but the plate gear that actually drives the spinner. I have kept these parts in hopes that I would eventually become "less afraid" to try to weld them back together. The handle isn't that critical but the gear wheel seem to need some accuracy.

Does anyone have any suggestions? Recently, I sent away for some EZ Weld TiG wire from a guy on Lopez Island in Washington State. I saw these used on a video on YouTube by "Mr. TiG" and he gave them a very good review. I'd like to use them and would be interested in knowing if anyone else has any experience with them or was Mr. TiG just blowing welding smoke?

Thanx
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The major problem that you will run into welding cast iron is it will crack as it cools. You will have to preheat and then use some method to let it cool slowly. I have used everything from asbestos blanket to burying the part in floor dry coupound. I have never tried to weld cast with TiG but have had some success with a special high nickel rod, made just for welding cast iron. You would use acel/org to gas weld using this process. Just be aware that the parts that you weld will not be as strong as they were before. Good luck with the repair you just have to use a process that will work for you.
 
I have stick welded it on a few occasions using stainless rod, preheating cast iron first, I never knew about cool down slowly til now but I didn't have issues, it wasn't super thick either.
 
The proper way to stick weld cast iron is pre heat it, but i have welded cast iron for 20 years not pre heating it with 99% success.If it has a crack drill both end of the crack so it don't run any further. Use 99% nickle rod, start out with a smaller rod weld a short run let it cool and weld some more on the root pass. Move on to a larger rod (1/8") and weld a little more trying not to generate to much heat. When done bury it in lime if you have some to let it cool slowly.
 
I've never used Tig but hear it works well. I've used nickel rod with the arc welder, usually good success. Preheat if possible, weld in short stitches and peen the weld with the point of your welding hammer. Peening it helps relieve internal stresses in the weld. Peen the crap out of it. When your veaing out the crack use a carbide burr in a die grinder, an abrasive disk contaminates the surface with particles from the disk. On large parts I post heat the part with a propane weed burner then let it cool slowly.
For small parts as I expect your handle and gear are I'd braze it with oxy / acetylene. Again use a carbide burr to vee the crack.

Greg
 
I am not a welder. I hear this comment a fair bit though. I have always taken it with a grain of salt.
Gas welding borders on being a lost art. People raised in the world of cheap TIG, think that gas is obsolete.
Brazing is STRONG! It is often stronger than the base metal. TIG may indeed be the best way to repair cast, but I have seen far more failed TIG than failed braze.
 
As Greg said peen the hell out of it between passes. I never let it cool completely between passes, but I hate wasting gas (read cheapskate). The post heat is also a good idea. Either bring the temp down over night in an oven, or use lime/sand, and a welding blanket to let it cool slowly. Mike
 
another idea for pre- and post- heat........use a charcoal barbeque/grill.
preheat as much as required, do the welding deed(with peening), and finally put it back on the grill and just let it burn down and out overnight....a nice slow cooling.
be sure you have a way to lift, carry and position the part before you get it hot!
-brino
 
If the cast iron has a very high carbon content welding it will prove difficult regardless of the method employed. As mentioned above preheating and slow cooling is desirable if possible, also using a nickle filler wire designed for the purpose (GTAW process) will help a good deal.

NI 99 filler works well. Likely to be entirely more expensive then you would like.
http://www.use-enco.com/1/1/44657-e...ice-bare-nickel-tig-welding-brazing-rods.html
 
For the kind of repair you are attempting nothing will beat brazing = Some preheat with the proper flux and you can repair large cracks and breaks that will be at least as strong as the original part, The problem with the nickel rod is as has been described before, it puts a lot of heat into a small area which creates large thermal stress. In addition, if the repair is not successful then the welded area has a much higher residual stress plus a much different base metallurgy which pretty much renders future repairs impossible. == Jack
 
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