Tig Welding Cast Iron

[Chip Watford]

I have always stick welded cast iron with good success but recently talked to a guy who told me that he tig welds about all of his engine blocks and pump housings.This got my curiosity up so I tried it and it seems to do very well.Low heat and tig-tectic or stainless filler rod.Preheat then cool slow.Seems like it would do well on small parts.Just thought I would get some opinions from anyone else who has tried this. Chip Watford

[Bryan Brooks]

As an owner of a steel fab shop I'll tell you that you can stick, tig or mig cast iron with numerous filler materials and have it look just fine. The problem is how strong the weld will be when complete. On some parts using mig with solid wire and shielding gas will yield a satisfactory weld. Other parts that are subjected to greater forces will require a specific weld process and filler material. You can always check with a welding supply company (that serves professionals, not your hardware store) as they will have reference materials and specific knowledge for each preocess and filler material to match with the job at hand. Few things in life are worse than removing a previous weld and rewelding or watching the part you spent hours repairing send a piece of itself across the shop as it fails.

[oldsteel1]

bryan,you are absolutely right! i am tryin to patch up a 1 1/2 worthington that was painted and pinstriped,but had cracks from top to bottom filled with jb weld and what i thought was nickel rod! tried nickel,inconel 112 &122! cut it all back out and started brazing.may give chip's technique a try.i am sure that would be on ac polarity but would high frequency be start or continuous?

[Kevin Lemmon]

Tig Welding Works Great On Castiron. 15 Yrs Ago I Welded A 6-8" Crack In The Cylinder Of A 3hp Novo.i Preheated The Whole Thing And Kept It Warm While Welding,let It Cool Slow.i Used A Cast Rod Used For Acetylene Welding.

[Bryan Brooks]

A few more thoughts. The forces on these parts may not be very high. I'm not sure what the cylinder head explosive pressure is on say a 1 1/2 hp engine. The higher the hp the greater the pressure may be. Also cast iron 60 or more years ago is not the same as today. No telling what was tossed into the mix back then which may cause certain makes break more than others. Any welding process has a good chance of yield good results on these old cast items. I believe that is why you can find so many people that have had success with so many techniques. But for the best results I would use filler materials designed for the type of cast iron you are welding no matter which process you use.

[J.B. Castagnos]

To get an idea what's going on when welding cast iron go to the lock-n-stitch site and click on cast iron welding, it's informative.-

[Ray Cardoza]

I've been told brazing and arc is the only way to go? claimed my highschool welding shop teacher. I've heard of it being migged with mild steel wire and other various methods other than brazing or arc welding

[Dan Ruffner]

Hey oldsteel, not AC, DCEN (Direct Current Electrode Negative) with High Frequency set to start, and stainless steel works great for cast, as well as Nickel 99 or Nickel 33. If in doubt, try some MG289 Stick rod with the flux sanded off.
my 2 cents worth
-Dan Ruffner

[Jim McIntyre]

I think J.B. did us a great favor. Look here:
http://www.locknstitch.com/CastIronWelding.htm

I'm curious as to other's comments on the rational against welding non-preheated cast pieces. Seems to make a lot of sense to me...

Cast iron will obey the laws of physics, even if you don't know them

[Eddie Cannon]

I have been in the welding business for about 15 years and the only way I can reliably fuse cast parts is to spray weld them using a Stoody spray torch and TG63 powder. The powder is a pure nickle powder and the part remains heated by the torch during the process. If the part will allow I usually preheat in an oven to 500*F then removed for welding. As with all cast materials cooling rate is critical. The Stoody torch is easy to master and I am not sure why more people don't use it.


Eddie Cannon

[mrxlh]

Good info from lock and stich, thanks for posting the links.