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Oxy Acetylene torch cutting cast iron?

John Madarasz

Stainless
Joined
Jan 1, 2007
Location
Exton, PA.
Considering trying to cut through some 3/4" cast iron on a repair I'm doing...I'll need to cut through not only the 3/4" cast iron, but also some nickel rod repair in the same area. I have a tip for my torch that's rated for 1"...should I even bother trying, or look at another avenue for repair, refab of part.

I can post pictures if needed, but really just want to know if it's possible to cut cast iron and built up weld. This is s structural repair...a broken foot pedal arm on an old heavy duty hollow chisel morticing machine that gets a lot of use fwiw
 
I'm for the grinder, too. Not only will you make a mess, you are going to cause the repair area to be all screwed up and almost ensure a failure. Grind it (even better, file it to finish), reinforce the joint with a couple of plates and screws, and then braze it.
 
That is what arc-air torches are for. Plasma too, if its a big-un. This is one time your oa torch is useless.
 
If you cut that much cast iron with an angle grinder, wear some sort of dust mask. Cast iron dust can really make one sick if much of it gets inhaled.

Post #6 is pretty much right. A plasma with sufficient capacity would be wonderful for this job.

Richard
 
Thanks for the info

Thxs to all for the good info... a big help. I didn't even try to O/A flame cut based on the excellent replies here, instead cut out my pocket on the band saw, then drilled across the cuts in a line and broke the cast out, quick cleanup on the Bport and ready to fit in new part. A quick, easy and efficient job...

Thxs agn everyone, and Best Wishes for a Happy, Healthy and successful New Year!

:cheers:
 
Air arc's are great when it come to cutting stainless also. Using one is like lighting a bunch of fireworks in your hand and waving them around. You also aren't likely to run one off a Tombstone buzzbox, as they do require a generous amount of power and air, but you can run them all day without having to change out bottles.
David from jax
 
Arc-Air should be avoided on cast iron because the air jet make the cast iron to harden. There is cut rods from different manufacturer that does a great job really fast. You can gouge and cut and it's relativly clean. Plasma is good too the air that flush the material is hotter than the arc-air....
 
This thread is years old, but I can add this:

Handbook-Manual Cutting

Where it is said:
Cutting Cast Iron Oxygen cutting of cast iron is difficult, but it can be done if you know how. It’s the graphite in cast iron which causes the trouble; although a form of carbon, normally thought of as combustible, graphite simply won’t burn; it must literally be washed away. To cut cast iron is slow work, and requires a special technique and plenty of patience. To cut cast iron, use a nozzle of the size you would use for cutting steel of the same thickness. Select a nozzle with maximum preheat capacity; a nozzle designed for minimum acetylene consumption simply won’t do the job. Adjust the preheat flames, with the cutting oxygen flame open, so that they have a decided excess of acetylene (the excess acetylene ”feather” should have a length at least twice the length of the inner cone). Make the flames as strong as possible. Then preheat the edge to be cut, all the way from top to bottom. The more you preheat, the easier it will be to get the cut started. Once you have done this, concentrate the preheat flames at a spot on the top surface and heat a circle at least 8 mm in diameter until the metal is actually molten. Open the cutting oxygen valve for an instant, just to blow the slag off the surface of the puddle. Then turn your torch so the nozzle is pointed 45 deg. away from the direction of the cut line, open the cutting oxygen valve wide, and start to move the nozzle back and forth in a progressive series of short arcs which intersect the cut line.
 
I would use my plasma.....it will cut it like it was carbon steel. The nickel won't even be noticed. If you do not have access to plasma ten a cutoff when on an angle grinder should do the trick.

Jim Colt Hypertherm


Considering trying to cut through some 3/4" cast iron on a repair I'm doing...I'll need to cut through not only the 3/4" cast iron, but also some nickel rod repair in the same area. I have a tip for my torch that's rated for 1"...should I even bother trying, or look at another avenue for repair, refab of part.

I can post pictures if needed, but really just want to know if it's possible to cut cast iron and built up weld. This is s structural repair...a broken foot pedal arm on an old heavy duty hollow chisel morticing machine that gets a lot of use fwiw
 
This thread is years old, but I can add this:

Handbook-Manual Cutting

Where it is said:
w.png

It is make easy to learn plasma cutting ;)
 








 
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