Another hare-brained idea

After playing around a bit with the plasma cutter, I've had another idea. I acknowledge up front that this is a dangerous thing!

The plasma cutter is way cool ... but not exactly inexpensive, especially to be able to cut anything very thick. O/A is considerably cheaper, at least as far as the basic equipment goes ... I don't know how consumables compare.

Would there be some way to combine the best of both? In O/A, the actual cutting is done by the oxygen, right? The acetylene just heats the steel up to the point where it will burn. Would it be possible to use something like the old carbon arc torch to heat up the steel, and then feed a jet of oxygen to do the cutting? This would require a much simpler and cheaper power supply than a plasma cutter (basically just a CC welder -- and IIRC, AC might actually be better than DC), but should allow cutting as thick a cross section as an O/A torch.

Of course, it may be that such an approach would simply result in the rapid burning of the carbon arc torch rod! On the other hand, if someone gives it a try and it turns out great, let me know. I'm not available to take any of the risks for development, but I'll be happy to participate in receiving royalty checks ...

Reply to
Andy Wakefield
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I do believe there is such an animal. Not sure what it is called. I am taking a beginner welding class and the teacher cuts thick steel to spot check weld quality with something that uses an arc and compressed air. Doug

Reply to
Douglas R. Probst

When I was a commercial diver in the 70's, we used a hollow ceramic coated copper alloy electrode tube, 350 amps of power, and 60#psi over bottom pressure to cut steel underwater. It would cut things topside, too, but was akin to a flamethrower. It was an awesome device, and I still see them in underwater shows today about salvage jobs, so guess they are still in use.

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Steve

Reply to
SteveB

Well, there are two tools that come to mind that do what of you speak: Carbon arc gouge and oxygen lance. There are other similar tools as well.

Arc gouge (usually used, as the name implies, for gouging, but also makes a good cuttin tool, uses high pressure air and a carbon rod. The rod is used as the electrode for the arc to the workpiece as in stick welding, and and air jet blown along it (or sometimes through it with a hollow electrode) blows the melted metal out, with some burning action as well.

The oxygen lance uses oxygen, blown through a hollow steel pipe (typically 1/4 inch pipe give or take). The pipe is ignited with an O/A torch or by striking a arc at the end. The action is self-sustaining after the initial lightoff, the steel burning quite readiy with the straight oxygen. The pipe is often filler with steel rods to provide more fuel. The ejecta will most happily cut steel, condrete, cast iron, or darn near anything else. Uses a LOT of oxygen. Quite impressive to watch.

Reply to
e

What about this:

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Seems dangerous and fun!

Eide

Reply to
Eide

WOW! Has anyone used one of these babies? What do they cost?

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Reply to
Doctor John

I haven't used one but I searched for a price and could only come up with this one link.

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Seems a bit spendy, but if you're cutting 4.5" steel all day it would (says the Dept. of Energy no less) pay for itself in two hours (as opposed to oxy-acetylene) see bottom of page:

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page 23 = Acrobat page 27)

I'd like to see it work, they say no slag !?!?

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Reply to
Eide

$1000 buckaroos is pricey - looks like you have to supply your own O2 tank as well - but it does come with a video .....

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Reply to
Doctor John

I have never seen any evidence that they work better or cheaper than Oxy-propane for cutting.

Reply to
Ernie Leimkuhler

Reply to
Andrew Mawson

I haven't seen it either, but the dept. of energy tested it and seems to have been very cost effective for cutting thick pieces. Here's the results of their tests:

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It sounds pretty damn cool, I wish I could see it for myself!

Eide

Reply to
Eide

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