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General Forestry => General Board => Topic started by: pineywoods on October 13, 2016, 10:03:49 PM

Title: Plasma cutting torch
Post by: pineywoods on October 13, 2016, 10:03:49 PM
I'm getting the wants (not necessarily need ) for one of these. I know next to nothing about them, other than all they need is compressed air and electricity. I have an oxy acetylene rig for most of my cutting and occasional brazing needs, but the price of acetylene has gone out of sight, plus the rent on the bottles. Anyone ever try to use a plasma torch and a brass rod to braze ? I have a wire welder to handle welding but if I could braze, then why not weld like a tig using stick rods or flux wire ?  Or maybe use argon co2 instead of compressed air ? 
Title: Re: Plasma cutting torch
Post by: coxy on October 13, 2016, 10:10:54 PM
they are sweeet but know nothing about brazing/welding with them
Title: Re: Plasma cutting torch
Post by: scsmith42 on October 13, 2016, 10:39:04 PM
Piney, I've never tried to braze with my plasma cutter.  The air flow through it is too severe to braze with, although I've never turned the air pressure way down either.  I think that if I did it would melt the tip since the air also cools it.

They use A LOT of air; the would evacuate a 250 CF tank of gas mix pretty quickly.
Title: Re: Plasma cutting torch
Post by: chevytaHOE5674 on October 13, 2016, 10:41:12 PM
You need a stout compressor that puts out decent CFM. Never heard anything about brazing with one.

Instead of acytylene switch to propane. Can cut and braze with it and costs way less.
Title: Re: Plasma cutting torch
Post by: 21incher on October 13, 2016, 10:55:47 PM
I use a Hypertherm 45 for Hand cutting, CNC cutting, & gouging old welds.  They require very dry compressed air to get a good cut and decent consumable life. It is a very concentrated pinpoint heat that vaporizes the metal so there is no way to weld with one with the plasma torch as they are designed. Once you get one, you will wonder how you lived without it. Hypertherm makes some of the best plasma cutters available, and they have a great website. :)
Title: Re: Plasma cutting torch
Post by: North River Energy on October 13, 2016, 11:11:58 PM
Another vote for propane. I use that for bulk cutting, and acetylene for finer work where I need more heat control.
You need different hose and cutting tips, but you can cut a lot with the contents of one barbeque grill bottle.

As to the plasma, they're handy, particularly for non-ferrous.
Title: Re: Plasma cutting torch
Post by: coxy on October 14, 2016, 07:16:08 AM
I used the same hose for propane and acetylene with no issues
Title: Re: Plasma cutting torch
Post by: North River Energy on October 14, 2016, 07:45:50 AM
^Just because you can, doesn't mean you should. From what I understand, hose rated for acetylene isn't appropriate for propane. On the other hand, Propane hose might be Ok for Acetylene?

Or maybe the whole thing is part of a retail hose conspiracy...

Regardless, when it comes to flammable compressed gas, the cost of specific hose is cheap insurance.

Title: Re: Plasma cutting torch
Post by: Dave Shepard on October 14, 2016, 09:22:02 AM
I'm switching to propane. The costs for tanks and acetylene is cost prohibitive. I know of acetylene hoses that have been used for propane for forty years.
Title: Re: Plasma cutting torch
Post by: Gearbox on October 14, 2016, 09:40:31 AM
You guys swiching to propane you will be back . Propane flame is so cold is takes forever to get hot enough cut . Plasma is great for what it is made to do .
Title: Re: Plasma cutting torch
Post by: Sixacresand on October 14, 2016, 09:48:36 AM
My BIL cut scallops in the disc on my harrow for me with a plasma cutter.  It made neat cuts. I want one too.
Title: Re: Plasma cutting torch
Post by: Ox on October 14, 2016, 11:26:51 AM
No, you couldn't braze with a plasma cutter.  The previous posts answered why.  It'll melt the tip real quick like.  That huge amount of air blowing through and around it cool it and blow the molten material out of the way.  Without it it'll be trouble.  I've had a plasma cutter for over 10 years now, a cheap chinese one from ebay.  The consumables are cheap and easy to find today and it does a really neat job on steel up to 1/4".  It'll cut 3/8" but you have to go really slow and it burns up tips quick and it's really pushing it.

I try to only use my torches for heating things when necessary.  All other cutting is either cut off wheels on a grinder, metal cutting bandsaw, sawsall or plasma.

The only thing I've heard about using propane in torches is you have to be more careful.  Why?  I remember years ago a guy had the torches "blow up" in his face because he was using propane.  What's the difference?

Any hose rated to handle gaseous materials should be good for any gaseous materials.  It's a molecular thing I think.
Title: Re: Plasma cutting torch
Post by: Chop Shop on October 14, 2016, 01:12:50 PM
I sold my plaazma cutter after ten years of trying to like it.

It was great if I was cutting clean flat plate formaking fuel or hydro tanks etc.   It sucked for anything else.

The high pressure air will blow the arc right thru anything it pointed at, so no scarfing out a weld or just cutting the top layer off of a joint.

A plazma cant heat up a frozen bolt.
A plazma will blow molten hot metal allover you. (think about pressure washing a bracket, nook or cranny , but hot metal instead of water)
A plazma EATS EXPENSIVE tips.  So if you dislike the cost of Acetylene you will really dislike the cost of constantly replacing tips.
The heat/cut cant be regulated once its set thats the arc you get during the whole cut.

My torch is a great tool. I love it and use it well.
It heats frozen parts.
It heats steel to bend it.
It heats to shrink/straighten tube.
It can cut with intense power or just barely all by the squeeze of the handle.
I can scarf a weld off of a bracket without blowing thru the base metal.
I can keep the same tip for 20 years with just a simple tip cleaning now and then.

Just my .o2
Title: Re: Plasma cutting torch
Post by: Bradm on October 14, 2016, 02:00:45 PM
Without going into the O/A vs plasma debate, there is a time and place for both.

As for actual plasma cutters, I've got a Hypertherm 30XP Air.  Self sensing dual voltage machine (110/220), built in air compressor, drag tips designed to be rested on the metal being cut, and easily portable (around 25-30lbs).  Good for 3/16 - 1/4" pierce.  I use it more than I would have thought I would.

If you need something heavier, they just came out with a 45XP (1/2" pierce, 5/8" production)
Title: Re: Plasma cutting torch
Post by: North River Energy on October 14, 2016, 02:07:08 PM
I know of acetylene hoses that have been used for propane for forty years.
Perhaps, then, I got hosed?
Quote
You guys swiching to propane you will be back
Um, no. At least not for bulk cutting. You need to account for a different flame effect on preheat, but it works very well otherwise.
Title: Re: Plasma cutting torch
Post by: chevytaHOE5674 on October 14, 2016, 02:33:59 PM
You guys swiching to propane you will be back

No I won't. I've been using propane for years and still keep a small Axy tank around in case I need to do a bunch of brazing or need to be portable (but the cost of Axy make me not use it). Other than that I have a 100lbs propane cylinder and I cut/gouge/pierce/etc just about everything I need to fabricate or repair on the farm with it. If somebody else were paying for my gas I would go back to Axy, but since I have to pay the bills and watch the bottom line propane is for me.
Title: Re: Plasma cutting torch
Post by: 21incher on October 14, 2016, 04:59:11 PM
I sold my plaazma cutter after ten years of trying to like it.

It was great if I was cutting clean flat plate formaking fuel or hydro tanks etc.   It sucked for anything else.

The high pressure air will blow the arc right thru anything it pointed at, so no scarfing out a weld or just cutting the top layer off of a joint.

A plazma cant heat up a frozen bolt.
A plazma will blow molten hot metal allover you. (think about pressure washing a bracket, nook or cranny , but hot metal instead of water)
A plazma EATS EXPENSIVE tips.  So if you dislike the cost of Acetylene you will really dislike the cost of constantly replacing tips.
The heat/cut cant be regulated once its set thats the arc you get during the whole cut.

My torch is a great tool. I love it and use it well.
It heats frozen parts.
It heats steel to bend it.
It heats to shrink/straighten tube.
It can cut with intense power or just barely all by the squeeze of the handle.
I can scarf a weld off of a bracket without blowing thru the base metal.
I can keep the same tip for 20 years with just a simple tip cleaning now and then.

Just my .o2

I can not agre with you about plasma. With my gouging consumables I can remove a weld with very little damage to the surrounding metal. It has less spatter then my propane torch had and only cuts about a .05 wide slot so there is less metal flying around. The consumables will last for close to 1000 feet of cuts if you have dry air,  the arc is controlled by the speed of cut and does not need adjustment,  & I can cut rusty old structural iron with no problem. The cost of gas for a torch is much greater then the cost of consumables for plasma. A torch is handy heating metal, but mine ( a 6" cutting Goss propane setup ) has gone in a box and not been used since upgrading to plasma.  :)
Title: Re: Plasma cutting torch
Post by: Kbeitz on October 14, 2016, 07:31:13 PM
I have it all but i do 99 present of my cutting with 6" cut off wheels...
Title: Re: Plasma cutting torch
Post by: Larry on October 14, 2016, 08:30:11 PM
Renting tanks?  That does sound like an expensive deal.  I bought my tanks outright about 40 years ago and can exchange them at either Praxair or Linweld when I need a refill.

This is my newest cutting machine.  Made by Kalamazoo in 1947 the capacity is 8 X 16.  Parts still available from Clausing.  Complements the Delta vertical band saw nicely.

(https://forestryforum.com/gallery/albums/userpics/10125/DSCF9117.JPG?easyrotate_cache=1476490971)

90% of my cutting is done on one of the band saws.  Curvy stuff is sometimes cut on the Bridgeport.  A cnc mill is very tempting but no plasma.
Title: Re: Plasma cutting torch
Post by: plowboyswr on October 14, 2016, 10:15:33 PM
I have a plasma and it works fine for what it's for. Not a real heavy unit will only cut 1/4" steel anything more and out comes the propane fired torch. Have even been known to braze light stuff with LP. Hook the gauges up to the 3  Acetylene tanks every once in a while to see if they're still holding. Other than that LP is all I burn.
Title: Re: Plasma cutting torch
Post by: customdave on October 15, 2016, 12:04:18 AM
I've had my cutmaster 51 plasma now 10 yrs now and love it, use it all the time, also use it for cutting aluminum & stainless which you can't do with a torch, but I'm also a ticketed welder & have to have all the toys....


                         Dave