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cutting thin stock



vault
02-05-2009, 07:21 PM
I bought one of those HF three tray carts and was cutting an opening for the argon bottle and had a really hard time maintaining the cut on that thin material. I tried current ranges from 100-200amps and air 75-60psi. The pilot arc got a good workout :cry: I probably hard to re start it 30 times.

Gadget
02-05-2009, 07:57 PM
Could it be due to the paint on the cart Vault?

Dan

KHK
02-05-2009, 08:45 PM
Someone on a previous post was saying that lower air pressure worked better on thin metal. They were saying 55 to 65 psi.
Just a sugestion.

keith

vault
02-06-2009, 11:42 AM
Paint could be..I've read that other people had no problem cutting through paint so I didn't consider it seriously...I could get it started but it would stop after a few cm. I thought it might be a combo of air pressure and amp being to high but I never could figure it out...maybe I was just getting to far away from the metal.. I know its some thing I'm doing either with set up or technique on this thin stuff because I have no problem cutting 1/4" and thicker material with it.

Gadget
02-06-2009, 12:21 PM
Vault,
I just noticed your current ranges. You should cut it down to 25 to 30 amps, perhaps even more. You are probably burning a bigger hole than the cutter can hold an arc on.
Dan

vault
02-06-2009, 01:48 PM
that's kind of what I thought was going on. what psi do you use at 25-30 amp?

vault
02-06-2009, 01:51 PM
I just realized I probably mis stated those currents I have a 200p so with the current knob set at 200amp I'm actually at 50 right so when I turned it down to 1/2 what I though was 100amp was actually 25ish right?

JOEBIPLANE
02-06-2009, 07:36 PM
Vault
:idea: When I cut my shelves I marked then drew ( SCRATCHED) the intended cut line for the circle with a sharp compass whiched scratched the complete circle line through the paint on the shelf I also installed the upper shelf inverted and by drilling a center pilot and running a string through the hole and using a plumb-bob to locate of the hole in the second shelf ( installed in normal method ( not inverted ) then I drillid a small hole ( 1/16-ish) and started the arc at the " start hole' ( set for perhaps 30 amps & 65lb +/- air pressure worked like a champ... BTW I cut it using a Miller circle cutter guide..result ??? Perfect hole.......I amazed myself
I then removed the second shelf...turned it over and slicedthe hole just like the top shelf ( much easier to get a neat clean swing with the circle cutter then trying to do it inside the corner of the shelf) re-install shelf & Walla! perfectly alined holes.
I also cut my holes about 3/8--1/2 inch oversize for the tank then slit a small sized rubber hose and placed it like edge guard around the hole. it cushins the tank and keeps it gently and quietly held in place REMEMBER 1/2' oversize only leaves 1/4" gap all the way around the argon tank...just right for vinyl or rubber hose from the big box store that will fill the gap....nicely :)
joe

vault
02-06-2009, 08:07 PM
I just scratched a clean spot and it started cutting great for 1-2" then I had real problems. The more I replay what I was doing I think I was getting to far away from the work piece triing to see the line I drew :roll:

Gadget
02-06-2009, 08:33 PM
Check with Simon, I think he has roller guides that maintain the proper cut distance.
Dan