What's the difference between a torch and a plasma cutter?

jpearson311 · 03-08-2011, 09:15 AM

I've been looking to buy a torch so I can heat and cut metal, but from what I understand, plasma cutters can do the same thing, they're just much more expensive. What are the differences between the 2? Thanks!

Jesse

roughsawn · 03-08-2011, 09:33 AM

I used to use a plasma cutter when I worked for a farm repair service. They use an electric current run through the gas or compressed air coming out of the nozzle to ionize the gas and create plasma ho.tter than regular gas torch. They literally blast through the steel. You can cut thicker steel faster.

fabrk8r · 03-08-2011, 10:02 AM

roughsawn is correct in that a plasma torch cuts metal using super-heated air (plasma) to cut through almost anything that will conduct electricity.

The advantage of a plasma torch over an oxy-acetylene torch is that the kerf of the cut is very narrow, allowing great accuracy, and the plasma is extremely hot, allowing thick material to be cut quickly with little blowout and less slag than with a conventional torch. Also, modern plasma cutting units are usually self contained with their own air compressor and filter system in the unit.

The disadvantage of plasma cutting systems, as opposed to oxy-acetylene or other fuel based type cutting systems is that you need a source of electricity and, if it's an older unit without it's own air supply, a source of clean air at a pressure of at least 30PSI (more PSI depending on thickness of material) . This isn't a problem in a shop setting, but if you are out in the field you will need some type of generator and air compressor with good filtration.

I noticed that in your post you mentioned "heating" of the metal. This really isn't feasible with a plasma torch, since the point of heat is very small. Trying to heat a metal surface, such as in a dent removal operation, will mar the surface.

jpearson311 · 03-08-2011, 10:05 AM

Quote:

Originally Posted by fabrk8r

roughsawn is correct in that a plasma torch cuts metal using super-heated air (plasma) to cut through almost anything that will conduct electricity.

The advantage of a plasma torch over an oxy-acetylene torch is that the kerf of the cut is very narrow, allowing great accuracy, and the plasma is extremely hot, allowing thick material to be cut quickly with little blowout and less slag than with a conventional torch. Also, modern plasma cutting units are usually self contained with their own air compressor and filter system in the unit.

The disadvantage of plasma cutting systems, as opposed to oxy-acetylene or other fuel based type cutting systems is that you need a source of electricity and, if it's an older unit without it's own air supply, a source of clean air at a pressure of at least 30PSI (more PSI depending on thickness of material) . This isn't a problem in a shop setting, but if you are out in the field you will need some type of generator and air compressor with good filtration.

I noticed that in your post you mentioned "heating" of the metal. This really isn't feasible with a plasma torch, since the point of heat is very small and trying to heat a metal surface, such as in a dent removal operation, will mar the surface.

Awesome, I see. I was referring to heating as in when a bolt might be too rusty to remove with just a wrench. Obviously I wouldn't want to use a plasma cutter here because it would just cut the bolt. Thanks for your answers. They have been very helpful.

Jesse

fabrk8r · 03-08-2011, 10:43 AM

Quote:

Originally Posted by jpearson311

I was referring to heating as in when a bolt might be too rusty to remove with just a wrench.

The best thing I have ever found to help break a rusted fastener loose is a few drops of transmission fluid and a little heat, such as from a small propane torch. Apply a couple drops of tranny fluid to the threads, apply a little heat (doesn't need to be red hot, but a little smoke helps) then, about the time it cools almost to the point of being able to touch it again with bare fingers, apply a couple more drops of fluid and wrench it off...I've almost always been able to break even the most stubborn and corroded fasteners loose this way!