Questions on Carbon Arc

[RAD]

Hi,

Thanks for any replies in advance! Any information, experiences and general knowledge would be greatly appreciated!

I'm new to carbon arc gouging. I have only been using this process for about four months now while at work. At work, I use a Miller Dimension 400 with an Arc Air K4000, shop supplied air and all the various electrode sizes. I especially like the speed and accuracy of removing welds and plates.


I own a 2003 Miller Bobcat 225/8500KW. I was contemplating on purchasing an Arc Air K4000 for side work/home. I mostly perform repairs on buckets, hoppers, heavy equipment and such.

My questions:

Is my welder capable of running carbon arc if so does anyone know the limitations of it? Would the K4000 be overkill for the amps my unit makes? Maybe try a K3000 or something less? Any electrode size recommendations for this unit if it will work?

I wanted to ask before I waste my hard-earned $$$ on something that will not do the job.

Thanks Again!

[fabricator]

3/16 rod. All you gotta do is look.

http://www.millerwelds.com/products/...en/bobcat_225/

[RAD]

Fabricator, Thanks for the reply!

I was not sure if the capabilities (duty cycle, real amp output) of the older machines were the same as the new upgraded machines they make now.

I could not find any info on my older machine since Miller upgraded the newer 225's with the 10kw generator and such.

So I guess I should assume the rest will be the same.

Thanks

[fabricator]

Its still a 225 amp machine so no difference there,you can look up a manual for your machine on the resources tab up top.

[MMW]

CAC uses lots of air. Make sure your compressor can keep up. I don't know the exact numbers but look into it before you buy. You might want to look into a smaller torch if your air supply is limited.

[MMW]

Arc Air K-2000 specs -- 450 amps max, requires 40 psi @ 8cfm minimum. 3/16 cac rods run in the 200-250 amp range.

[RAD]

Thanks for the info.

My portable compressor puts out 26.2cfm at 100psi and 23.4cfm at 175psi. I should be "good to go" on the compressor I hope.

Basically for the gouging torch I could get the K2000 because at max my machine only puts out 225 amps and the K2000 is 450amp max? The K4000 would be overkill.

Thanks

[paulrbrown]

Rad, the Bobcat will have a very hard time running carbon arc as it does not have the voltage needed, plenty of amps/duty cycle, but carbon arc needs more than the Bobcat will produce. I went through this with mine and it took awhile to find the info that set me straight. I believe it is over 30 volts as the carbon needs quite a gap. Miller does not list the machine as CAC capable and my dealer only thought it was duty cycle, they had no idea why.....so, Hope this helps, Paul

[seattle smitty]

Maybe you can live without carbon-arc gouging, if you have gouging and flushing tips for your O-A rig, AND if you buy a box of 1/8" chamfer rod or gouging rod, one of the world's great inventions. With your Bobcat, which is what I've been using, dial it up to the top of the range, straight polarity. Chamfer rod is great for grooving cracks in equipment when you don't have a proper compressor or any at all. Try not to forget to change the polarity back when you start welding . . . .

[HAWK]

CAC can ruin...

Please be careful when carbon arc cutting and gouging with smaller engine drives. Frequent use of the CAC process can eventually ruin the small armatures used in the Bobcats and smaller machines.

The newer units which Miller rates as CAC capable may not have the same problem. I have found skimming rather than deep gouging with carbon rods is more effective with the smaller engine drives. A healthy air supply is also a plus.