View Full Version : Giving up the gas torch for plasma so what to expect
I store low power explosives in my garage. Don't worry, it's in the ATF approved magazine and has local fire marshall and ATF happy with appropriate permits. That said, my local fire chief has talked to me and would "really like" to see me get rid of my Oxy/Propane setup that I keep in the garage. I'd prefer to listen to him so will likely sell my victor superrange setup that I have.
So here's my issue. Most of what I used the torch for was cutting off bolts on the vehicles I'm working on, and for very light fab work. If I get a plasma that is rated for a quality 3/8" cut, would that be sufficient to cut heads off a bolt that has something like 1" head on it? Obviously I may need to take several swipes to cut it off, but my main concern is with recessed bolts/nuts - like say a captive nut inside a truck frame - would I have to get my ground clamp inside the frame etc? thx
11-12-2007, 10:02 PM
It's not so much the work clamp as it is the plazma torch. It isn't real conducive to hard to reach places.
A torch is hard to beat sometimes. A plazma won't descriminate between two pieces like a torch will . I suppose if all you had was a plazma you'd soon learn to get by.
11-14-2007, 10:55 AM
i don't think the FD cares whether you make considerable sparks/hot bolls of slag with a fueled torch or a electrical torch, just that you stop making sparks/slag near the explosives, low power or not.
11-15-2007, 08:15 AM
i don't know if you'd be able to cut the 1" head off. i do know they make gouging tips for the plasma cutter, and that might help you make some headway. when i buy my plasma unit next year, i plan on buying the gouging tip, so i'll have that capability if needed.
11-18-2007, 08:08 PM
The oxy/propane is prob not the heat/sparks/slag drops from the unit, but more like a safety issue for the responding fire fighters. The magazine is relatively safe in a normal house fire. The oxy tank on the other hand has a tendency to add a rapidly expanding oxidizer in a less than polite manner in a fire. The propane tank is lower pressure, but the leaking gas will travel near the floor searching for something to light it.
Now that the choir has been preached to, the oxy/propane rig is safer when handled correctly than the small can of paint thinner setting next to the water heater.
I think a plasma will cause you issues in getting in to tight places and as other have said, it is net nearly as discriminate as a torch.
11-19-2007, 11:38 AM
I wouldnt, couldnt be without a torch. Those bottles sitting there turned off dont have squat to do with fire saftey. It wouldnt be the first time some have gone thru fires, happens all the time.
12-02-2007, 09:42 AM
Could you just keep the explosives somewhere else?
What are they? And why do you have to keep them out there?
12-02-2007, 11:25 AM
Being the owner/user of both a O/A outfit and a plasma cutter (1/2" cut rated), I use each for different things. I find it safer to use the O/A outfit for cutting thicker steel, cutting off bolt heads, etc. with less heat and problems that if I use the plasma cutter. The plasma cutter is less than desireable for trying to get in tight places, but great for cutting plate (1/2" or less), pipe, tubing, etc. where access is not a problem, and where the type of metal is not steel. I have observed the sparks generated by the plasma cut seems to be more dispersed and hotter than that produced by O/A outfit. My most recent 'screwup' in cutting 3/16" sheet metal on my garage floor was the result of me using the plasma cutter. Prior to obtaining my plasma cutter, I would cut the sheet metal laying across 4" angle iron. Since I purchased my plasma cutter, the occasion arose for me to cut more 3\16" sheet metal. This is one of the reasons I purcased the equipment anyway. Once again I laid the sheet metal across the same 4" angle iron. When I was picking up the pieces after cutting, I got a shot of reality that I was not expecting. Previously when I used O/A torch, there would be some discoloration of the concrete that was easily removed by a small amount of cleanup. After using the plasma cutter, the damage was considerably more than discoloration. It burnt into the concrete, destroying the surface that will take some serious repair work.
Although I love my plasma cutter, if I had to choose between one or the other, I would choose the O/A setup.
Just my 2 cents worth.
12-03-2007, 12:17 PM
After using the plasma cutter, the damage was considerably more than discoloration. It burnt into the concrete, destroying the surface that will take some serious repair work.
i would expect nothing less, the plasma is >30,000F, the O/A <6kF. the plasma continues well past the kerf (plasma cutting is a mechanical process), the O/A stops pretty much at the bottom of the plate (O/A is a chemical process).
12-03-2007, 09:08 PM
My plasma cutter has been on the job about three weeks. Tonight I decided to give it a work out. I use a small sheet metal plate with aluminum fins (1/4 inch) radiating from the center as my all purpose table top over plywood. I cut, out in
the air off the end. Tonight as I finished a four inch cut across some 16 gage material, I saw this flash. Yep, bench was on fire. Was only a small thing. Don't like any kind of errors though, they grow with too much ease.
I just finished the spark trap but I am now wondering if I made it large enough. It is 4x4x4 from 1/4 square tube welded bottom and movable top. I am hoping the sparks won't shoot up out of it. It is for really small parts from bar stock.
12-04-2007, 07:33 AM
I was once cutting 1/4 inch steel with O/A and couldn't get it to cut through and ended up scarf cutting it. Couldn't see the the 1/4 inch steel gusset welded onto back side or torch cut it until front plate was cut. With O/A O2 jet is oxidizing (burning) curf line in preheated steel. Most of the heat is in plate your cutting. Plasma cuts with super heated jet of hot gas (air) that melts and blows molten steel away from cut line (curf). Ive seen plasma cut what was wanted and steel almost 1 inch away on back side.
12-04-2007, 09:07 AM
Many thanks for the info about the plasma cutting beyond the work. I have read it all but retention and application for every situation - well success depends greatly upon experience in many cases. I have studied what is going on but when the hood is down and you are trying to keep th wheels on the guide and not rock the torch other things take place. Thanks again. I guess my good fortune is that it was all non critical and no one was endangered. Never read one word about the plasma cutting beyond the work piece.