precautions.
Figure 18 shows the plasma
area in my main shop. This is a 12’
x 12’ area surrounded by welding
screens. The floor is covered with
cement board with ceramic tiles
around the lower edges to cover
the transition from the cement
board to the welding screens. In
addition, I have fiberglass welding
blankets that cover things like
corners and also hang from the
ceiling.
I also keep several fire
extinguishers nearby, just in case. Please note that I have
several CNC machines, laser cutters, and ever 3D printers. I
never run the laser or plasma cutter when I am not in the
shop to watch them. This would invite disaster.
In reality, I get more sparks and slag when doing MIG
welding than I do with the plasma cutter, but it’s nice to
know I have things covered.
Plasma Operation
The plasma cutting operation
will cut through paint, rust, or mill
scale. The problem is that the work
clamp must make good contact
with the bare metal, so it must be
clean where it comes in contact
with the stock to be cut.
Use a flap sander or grinder to
clean the stock where you want to
attach the work clamp as shown in
Figures 19 and 20.
Free Hand Cut
To make a free hand cut, I start the torch just off the
edge as shown in Figure 21. You want the torch edge to be
close enough to complete the circuit, but off the edge
enough to keep the splash to a minimum. This will
drastically increase the life of the consumables. Note that if
you are not using a drag tip, you must keep the
torch about 1/16” from the surface of the stock.
My Powermax65 hand torch came stock with a
drag tip. My Everlast 50s did not.
In Figure 22, I am only cutting 22 gauge
material at 20 amps, and am pulling the torch
about as fast as I can while still keeping an eye on
the cut. I actually find cutting thinner metals more
difficult than thicker ones — especially with the
50s.
What you will find is that every single wiggle,
pause, and tilt will be translated into the cut. The
more practice, the better your cuts will become
(Figure 23).
A Little Help
What can we do to help our free hand cuts?
As with any cut, add a straight edge. I created a
magnetic straight edge shown in Figure 24. This
Figure 21
Figure 22
56 SERVO 09.2016
Figure 18
Figure 19
Figure 20