all is well again.

All's well that ends well!

 

I wanted to share some photos of a recent repair that I did. This fellow knocked over his cast iron drill press stand and broke the flange off of the tube completely. I repaired it & all is well again.
View attachment 1760873 View attachment 1760875

Details?

What rod did you use? I'm assuming it's stick of course. Looks like stick. Amperage? Preheat? Post heat? Wrap it in a welding blanket? What was the ambient air temperature? Barometric pressure? Did you remember to brush your teeth?

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I have used brazing and tig for welding most cast iron. For larger jobs I have stick. But not for liquid.

Brazing and tig you see bad spots in cast iron. It hard to see bad spots using stick and you can get leaks.

Dave

I wanted to share some photos of a recent repair that I did. This fellow knocked over his cast iron drill press stand and broke the flange off of the tube completely. I repaired it & all is well again.
View attachment 1760873 View attachment 1760875

 

I furnace welded (an Oxy-Acetylene process) this piece, Oxweld 30 tip. Filler was RCI.

 

Oh, very nice. I was assuming stick based of the bead size and the soot and sh.t around it. I usually end up using a knotted cup brush on a grinder to clean my cast welds.

O/A is, in my opinion, the best welding process for cast iron. Stick is good, but requires a lot more care the make the bead wet out, not undercut, not crack, etc. Never tried TIG or MIG on cast... couldn't imagine how much a 10lb spool of Ni99 would cost.

 

Nice. Could you share more about the process?

 

It not mush to share it torch brazing and you watch to see if bronze is glued to cast iron about like soldering.
Then fill the gap

Dave

 

The piece is brought up to temp (temp depends upon your goal, equalize expansion and contraction, or anneal), and the piece is welded within the furnace. It's not removed until it's cold, so there is no danger of warpage or cracking from thermal shock.

As for the actual welding, cast iron has a very fluid puddle, and likes to drip away if you're not careful. Good filler that's sound, good goggles that you can see porosity and scum with, and a steady hand make it somewhat easy.

 

Did O/A cast iron welding in school decades ago. Filler was a triangle shape and you had to dip in a powered flux quite often. The cast test plates had to break rather than the weld to pass. Right beside the weld was a fail. Interestingly high temp brazing would break the same way. That's why brazing is often recommended as long as the piece doesn't get real hot in service like an exhaust manifold.

 

I'm glad you shared this. It's a process I'm not familiar with.

View attachment cast iron welding.jpeg Still not 100% understanding it, but it looks like something to look into. I generally use a Nickel rod, and either weld it cold, or weld it preheated. Depends on the overall mass, and ability to do a decent preheat. Either way will produce a good result if you adhere to the proper procedure.

Anyways..............Cool!!

 

I'm glad you shared this. It's a process I'm not familiar with.

View attachment 1761215 Still not 100% understanding it, but it looks like something to look into. I generally use a Nickel rod, and either weld it cold, or weld it preheated. Depends on the overall mass, and ability to do a decent preheat. Either way will produce a good result if you adhere to the proper procedure.

Anyways..............Cool!!

What part are you having trouble understanding?

 

The furnace bit. It seems like a stretch for most stuff that I encounter. I don't have enough preheat capacity, let alone a furnace to place the piece in. I'm thinking it's way beyond my means. But!!!!!! It's one of the best cast welds I've seen. Nickel rod sucks for controlling a puddle, at least for me. The lower Nickel stuff is reasonable, but the high Nickel stuff is insane.

 

View attachment axle pin63.jpg This is the low Nickel rod.............welds sort of ok, but still doesn't flow like a regular mild steel rod. For me, it's a real challenge.

The machinable stuff runs worse. Maybe I just don't use the stuff enough.

 

It's not that high tech. My furnace is a pile of bricks and my fuel is charcoal.

 

I have to try it. I have one Hell of a time with cast iron, especially padding for remachining. I'll get some pics......................

 

be a while, I just got internet, and my computer up and running. Everything is real slow

 

The RCI rod is completely machinable as long as you don't mess up the heat treating in the furnace. It lays down grey cast iron that's about BHN 180. The only major issue I have is with porosity on low quality castings, but with enough flux and stirring you can get the source of it out.

 

View attachment axle pin25.jpg I almost forgot to get back to you on this.

I got where I needed to be with the Ni99, but it's like pouring putty on the metal. No real puddle control........it just flows. I don't like it. Positively sucks for building up a part.

View attachment axle pin124.jpg While it's supposed to be readily machinable, I found it to be less than ideal. Exceptionally hard, and because I had to side mill it........it liked to push the tool off the face of the part. I know a lot of that is because I don't have a very rigid mill..............but Jeeeeeeez!!!!

So..........if the process your using is depositing actual iron, I'm all for it.

 

I have never been fond of the 99% nickel rods. Some of the new, and very very expensive rods are said to work ok. The owner at the machine shop I work at will use magnaweld rods for small cast iron repairs, his cost is about 40$, per rod!! The results are often porous anyways.

Another fellow told me that "super cast 90" by arctech, and Ni-rod55 by special metals work well. He had photos of his work and it looked nice, but who is to say how well it machined.

 

I'm getting porosity too. You just don't have any idea what you're laying down with this stuff.

I didn't go whole hog on the price........some fairly cheap(YEAH RIGHT:realmad stuff from the LWS

View attachment axle pin27.jpg

 

I have an unmarked metal can of some kind phosphor bronze stick that looks old enough to have come over on the mayflower. Came out of a free box at a yard sale. It's saved my butt multiple times on broken cast parts. It lays down just soft enough to cut with carbide on the lathe or mill. Doesn't leave pinholes in the weld. Runs like garbage. Slag flows all willy-nilly and the arc wanders and fingernails regardless of polarity or AC. I'll be sad when I use the last stick.

I've used Eutectic Xuper 2240 a bit on big money repairs. It's ±$500 for 10lbs, but runs pretty smooth and easy. Leaves a medium soft weld that seems pretty tough.

Good ole Eutectic 680/Super Missile Weld/312 SS has also worked for me in a pinch, but you have to limit to shorter than 1/2" long welds at low amps and wait, wait, wait for it to cool.

An ol' top welder told me the best way to stick weld on big cracks was to vee them out, butter both faces with nickle rod, then weld them together with 309 or 312 SS. That way you get the ductile bite of nickle, but with a cheaper/easier bulk fill. I have never tired it to see.

 

Have done this on an old farm tractor muffler. Worked better than I thought it would Nicel rod followed by 309ss after a little pre-heat.

 

From what I understand.............the Nickel in the buttering pass prevents the migration of carbon into future passes.

 

The main issues with cast iron welding are 1. The carbon, & 2. The hot shortness of the material.

Most of the carbon in grey cast iron is free graphite, but upon melting and rapidly cooling, the carbon will stay dissolved, creating cementite (iron carbide) which is extremely hard (600-800 BHN) and extremely brittle.

Cast Iron is also very brittle at high temperature, so any heavy welding has the possibility to crack the iron along stress points as it expands and contracts.

Furnace welding solves the expansion and contraction issue, and gas welding solves the cementite issue.