Cast iron welding rod

[evfreek]

Hi.  I remember seeing a post somewhere about making your own cast iron welding rod in a forge with a mold with triangular channels in it.  I cannot seem to find it now.  It was only of passing academic interest when I saw it earlier, but now is more interesting, since I performed a seemingly successful experiment with a cut out from a broken street drain cover.  Commercially available rod is hard to fine.  There is someone on Ebay selling for a high price, but admittedly it is less than the alternative (fiddly cut with a hacksaw).  Does anybody remember anything like this?

[Frosty]

I think it was brought up years ago but only as a speculation IIRC. Are you looking in a welding supply? Gas or electric cast iron welding rod is usually on the shelf here and in a goodly selection. If they don't have it it's on order. 

Rather than Ebay how about looking on the: Stoody, Miller, Lincoln, Hobart, etc. sites for the rod you need? Go to the manufacturer and ask experts while skipping the middle man's cut.

Frosty The Lucky.

[Kozzy]

Um...commercially available rod for cast iron is not really hard to find.  There are a LOT of variations available depending on what you want to do though.  Some of those are a bit expensive because the constituents to get a good weld on cast iron often take the more expensive "herbs and spices" in the rod such as lots of nickel.

True "cast iron" rod is also available and is typically used for gas welding of cast iron.  Takes a LOT of heat so you can't really use a small torch head.  For simple and less structural fixes, you can also use stainless steel rod if you follow some procedures:  It doesn't tend to pick up a ton of carbon from the parent metal so is a bit forgiving on the cracking problem.

So...I'm a bit confused about the problem you are chasing here.  Maybe you just hadn't dug deep enough about sourcing rod for cast iron?

Here's a link to one I posted long ago when I had some unidentified rod--and there's a good video included from Eastwood using true cast iron rod.

[evfreek]

Hi.  I've got plenty of the Ni-99 rod.  I meant the cast iron torch rod, like Cronatron 22. Detroit torch has some on their web site, $39 for 5 sticks, sold out.

[G-son]

On ‎4‎/‎29‎/‎2019 at 9:15 PM, Kozzy said:

True "cast iron" rod is also available and is typically used for gas welding of cast iron.  Takes a LOT of heat so you can't really use a small torch head.  

I'm guessing many members here have other ways to preheat cast iron items, either with propane, coal fire or something along those lines. Reduces both cracking problems and the amount of heat the welder has to supply.

As for cast iron rods, Kastweld 111 may be another option. Another old trick is using old piston rings, they are made from good quality cast iron (some modern rings are not). Tried it with my Dillon (a.k.a. Cobra/Henrob/DHC 2000) welder, worked well.

[BIGGUNDOCTOR]

Welding cast iron is a bit of a hassle to do it right. Rods run around $50 a pound, you need a peening device - I use a large inline needle scaler, and a way to cool it down very slowly - I use gray wood ashes.

Some rods use a preheat, others do not. Prep the weld area, lay a short bead down, then peen it as it cools from red heat to black. Brush the weld, and repeat as necessary. The issue with cast is it has a vastly different coefficient of expansion than the weld material. The weld bead shrinks faster, and rips away from the edges. That is why you peen the weld as it cools - spreads it sideways keeping the edges together. When done, bury it in ashes and let it cool overnight.

 

Easy peasy way to repair those items - brazing. One and done way to make it hold the first time.

[arftist]

Brazing is good for all but very high temp parts such as grates in a coal stove.

In areas of high heat, nickel is better.