Cutting cast iron

Martin Eastburn fired this volley in news:6yOov.34906$ snipped-for-privacy@fx06.iad:

Oh, Martin! Termites don't eat metals! Lloyd

OK, I have my answer.

Wet 6010 electrodes work really great and cut cast iron like butter.

I tried them today at work and the result is excellent.

You do "dip - cut - dip - cut - etc" and it is very easy to do. One needs to get a little hang of it, but once you do get it, it is very straightforward.

I can use my lowest paid guy to do it because it is so simple. It is an ugly process, but it works great and only needs a working welder -- no air, plasma etc needed.

I will experiment some more to see if I can use 3/16 electrodes instead of 1/8.

Thanks a lot to everyone.

But they burn pretty well.

"Ignoramus27974" wrote in message news:0KCdnRADP8gntznOnZ2dnUVZ snipped-for-privacy@giganews.com...

Do you need more current than the 200A an inexpensive transformer machine provides?

-jsw

I used 1/8" welding rod and 200 amp current. It worked well. 250 amps was too much and would melt the welding rod if I forget to dip it at just the right time.

For real jobsite work, I want to try 3/16" rods at 300 amps. This is my current practical limit, because the biggest stick welder that I have at the moment (just taken out of my store) is a 300 amp welder.

I also have 1/4" 6010 rods, and for the future will look for a cheap old ugly 500 amp stick welder.

Ability to quickly cut cast iron castings is invaluable to me.

Thanks.

I try to limit my questions and suggestions to what the average hobbyist might own or be able to buy today, not rare or specialized stuff I found at an auction. For example I haven't pushed the Clausing mill or South Bend Heavy 10 lathe when someone asked for a recommendation.

If it is Meehanite perhaps it has higher scrap value to someone?? I think they add Nickel etc as well as change the process.

-jsw

I understand. In the places where I work there is usually a lot of 3 phase current available. Old stick welders are cheap and plentiful, and good.

None of this applies to an average "hobbyist", but then again, a hobbyist would not need to cut cast iron castings, either.

No, they pay the same for all cast iron.

I was pretty sure that the 6010 electrodes would work. When I used them on steel I was amazed at how fast everything melted. I had forgotten about using wet rod. It really does help because it keeps the flux from burning off so fast. Thanks for posting your results. Eric

It is a very nice method. Dip the entire electrode and the end of the electrode holder, to keep everything cool.

I believe that the water keeps everything cool, but it also enhances the cutting action, with more steam helping push the molten metal out.

don't you love spell checkers..

Termites eat wood and concrete. Thermite is what I wanted.

Thanks LLoyd or is that Loyd Lloyd.. I've seen it all three ways!

Martin

Full of gas and lots of raw cellulose around! Martin

A little follow up on this. I have a job where several castings need to be cut on Monday. So I spent the weekend getting a setup ready for this job.

I have put together a nice package, a Miller 300SS stick welder, welded it to a heavy duty cart, with heavy 6/4 30' input cable and heavy 2/0 welding leads. Also with an aluminum box for storing stuff, a clevis shackle on the lifting eye for lifting it with chain etc. A very nice package.

Tried cutting cast iron using this rig and 3/16" 6010 rod (Lincoln

It works really well, cuts metal very quickly, blows molten metal away, etc.

I have not really decided, yet, if it is better to cut from the bottom up, or from the top down.

Run 3/16" 6010 at around 250 amps DC electrode Positive. Dip the rods in water before arcing to get a little more oomph.

Messy as hell, but it works. Use a sawing motion on the heavier sections to clear the cut all the way through. This also puts so much thermal shock into the heat affected zone that it makes it easier to crack the cast iron.

Wear full leathers and a welding hood.

Ernie, thanks. I tried messing with it by myself. I found that it works with 3/16 6010 at DCEN and 300 amps.

I will try to do exactly as you say and use 3/16" 6010 at 250 amps DCEP. I will do that today on the actual machine and will post the results.

It is not even messy, very nice.

Thanks Ernie. Today is the day to try it, I will set exactly as you say and will report back.

I did try it in my shop on some small pieces and it works very well.

OK, here's the result.

DCEN works better. The best setting was 3/16" 6010 rod, DCEN, 300 amps.

You really need to get the hang of it and use the "sawing" motion, "pushing" metal out of the cut. Once you do get it, cutting is as easy as eating pie.

Dip each rod at least twice, before cutting and when it is half burned.

The first casting took me almost an hour to cut.

The second, my guy cut in only 15 minutes because 1) We understood how to do it and 2) we realized that we only need to cut ribs and hit the casting with a forklift counterweight.

I have loads of 3/16" 6010 so I am all set for the current and some future jobs.

When I re-read my post I realized I got it backwards. DCEN works better than DCEP for cutting.

But try the water dip trick. It really does help.

Yep. I tried both and found that DCEN works better. This is what I thought from the beginning, DCEN gets work hotter.

DCEN and 300 amps work wonders. I putzed around a lot and found that a sawing technique works great. The electrode blows out everything on its path, maybe 1mm of material at a time.

I would say it is about 2:1, 2 cubic inches of molten metal for each cubic inch of electrode -- just my feeling.