Cutting Metal with a Stick Welder.... OK?

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Old 06-24-05, 06:41 PM
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Cutting Metal with a Stick Welder.... OK?

I have many pieces of 4" x 4" x 5/16 angle iron that I need to cut and notch.

I have a Miller engine driven stick/mig welder and plenty of 1/8 inch 7018 electrodes. This welding rig is not a "homeowners special".

I also have a company supplied wimpy Milwaukee 4 amp Sawzall and a wimpy Makita chop saw that are not up to the task of cutting this material effectively. They will not fix/replace my tools if I bring them in and use them, so that is out of the question.

The boss will not buy a portable bandsaw, yet still complains that it is taking too long. Go figure.

So, the question is, is it safe to crank the welder to 11 and just burn the cuts, or will that damage the welder? I tried a small sample, and the results are acceptable for the job. The welder isn't mine, and I do not want to break it. I think that purposefully burning through the metal on a high amperage setting is different than burning through once and a while... but I may be wrong.

Along the same lines, a local hardware store sells a rod specifically designed for cutting metal. I have never used this, and there aren't any directions/guidelines on the packaging (except for the 15 foot shower of sparks warning... ). Anyone have any experience with this stuff?
 
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Old 06-24-05, 08:09 PM
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As long as you stay within the duty time of the machine you can do what you want.
What's the model number and model name of the miller welder ?

A 20% duty time,
You can weld 2 minutes out of 10 minutes, the remaining 8 minutes you let the welder cool down.

A 40% duty time, you weld for 4 minutes, let the welder cool down 6 minutes.
 

Last edited by GWIZ; 06-24-05 at 09:04 PM.
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Old 06-24-05, 09:58 PM
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The cutting idea is right, the duty cycle of the engine drive is probably adequate, but I would not use 7018 rod for this purpose. Better choices would be either 6011 or 6010 which have a much greater "digging" force. I have done this with 6010 and it works very well, the edge of the cut will be fairly rough however, since the arc is not focused, as it would be with a plasma cutter.
Don't run the rod above the upper end of its amperage range or the flux coating will bake off due to the heat. For instance, the 6011 flux is usually a flat white color. If it starts going brown along most of its length, the amperage is too high.
The leads will get a little warm as well, so be sure to stretch them out rather than leaving them in a coil.
 
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Old 06-24-05, 11:56 PM
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I have cut metal with a welder. We used to soak the rod in water to avoid the flux flying all over. I have also used Nirod for cutting cast iron. The rod at the hardware store, if it is also what I have used has a black coating and feels like it is hollow. End of rod looks like it was pinched shut. Works well though. Flying sparks are its only downfall. All of these methods will work. Good luck.
Test your amperage until you get the the cutting power you need, No use going overboard.
 
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Old 06-25-05, 02:14 AM
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cheap mans air arcing

one other way that i have cut metal with a stick machine is to use carbon air arc rods in your stick welder and have a friend (or your other hand) with a air nozzle blow at the arc. same principle as an air arc setup. may sound stupid, but i have done that before. what can i say, i didn't have the money at the time for an air arc stinger. i think the air arc rods are cheaper than welding rods.

6010 - 11 i have also done. also used the specialty rods that are meant for cutting. it all works and the results are what i expected.

rob "redlight"
 
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Old 06-25-05, 06:05 AM
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The welder is a Miller Bobcat, pretty sure it is a 250. Both the Miller 225 and 250 models are rated at 225A, 100% duty cycle at 104* F in the stick welding mode, so I guess I am covered.

Anywhere I can go to learn about the different basic rods and their proper applications? I have a feeling that the shop just sends out whatever is on sale at the time....
 
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Old 06-25-05, 06:44 AM
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Anywhere I can go to learn about the different basic rods and their proper applications?

I have found publications from Lincoln Electric to be very comprehensive. Look at http://www.lincolnelectric.com/ and review "consumables". Many projects can be done with either 7018, 6011 or 6013, so I would start with those 3.
 
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Old 06-25-05, 01:23 PM
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The best way would be a cutting torch. I've used my engine drive to cut 1/2" thick steel. I was using allstate rods designed for stick cutting, also used 6011 and found not much difference. I agree with IBM, I've heard 6010 are best and 6011 will work. I found using a sawing motion pushing the molten metal out the bottom from above works well. Doing overhead or verticle harder because gravity isn't allowing molten metal to fall. Tried using compressed air along with the burning rod and wasn't as helpfull as I'd hoped. good luck.
 
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Old 08-04-05, 03:35 AM
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I have some special 'cutting rods' from a company called ALCAM. They're supposed to have some special properties that make them cut rather than weld. Directions say to arc then use the rod like a saw.

My experience is that they weld just fine.
 
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