purchased a 60 gallon 11. 5 CFM air compressor for the
main shop. This is the minimum I would recommend for the
The amount of the gas/air is just the start. In addition
to air flow, you also need very clean dry air. For the 50s
setup in my garage, I’m using the filter/dryer shown in
Figure 11. For the Powermax65 in the main shop, I
am using the larger filter/dryer shown in Figure 12.
The dryer portion of the filter uses a desiccant
that once depleted (Figure 13), can be dried in an
oven or microwave (Figure 14). For heavy use of the
plasma cutter on a CNC machine, you may have to
resort to other drying methods.
Improper ventilation when plasma cutting can get
you sick very quickly (or worse) — especially when
cutting painted or coated metals. For a garage, you
can move the plasma cutter near the door and use a large
fan to blow the fumes and smoke outside. For me, I have
found that a downdraft table vented to the outside works
Figure 15 shows a downdraft table I created for my
hand torch. It uses a 1500 CFM fan to suck the fumes and
smoke down and out through flex hose that exits the
garage via a window insert. While this works very well, a
fixed set of 8” stove pipes will allow more air to flow, thus
increasing the efficiency of the downdraft table.
Figure 16 shows one of my smaller KRMx02 CNC
machines converted to plasma. It has the same 1500 CFM
fan connected to a set of stove pipes that exit the shop.
One of the side effects of plasma cutting is plasma
dust. This black nasty dust will cover everything if it is not
dealt with. The downdraft tables help a lot, but when
piercing you get a lot of material bounced off the top of
the stock until the pierce cuts through the material. To help
with this, I have a rear wall and a front door on the CNC
that keeps a lot of this dust at bay so that the downdraft
can take care of it.
One last line of defense against the plasma dust is a
shop air filter like the one shown in Figure 17. I run this
filter when I am plasma cutting on the CNC. It does a great
job at keeping the dust to a minimum. Notice how the pre-filter is almost black. It is actually a white filter. My filter is
on a rolling stand so I can position it for other tasks as well.
Plasma can throw a lot of sparks. Most of these don’t
amount to much but when cutting thicker materials at
higher amps, some rather large molten blobs can get
thrown beyond the control of the downdraft table —
especially during the initial pierce operation of the cut.
My main shop is a converted barn with an insulated
wood floor. It is all very flammable, so I need to take
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