On Sat, 03 Dec 2005 02:37:01 GMT, Michelle P
wrote:

Is your incoming gas pressure high enough? You may ot be clearing the
material quickly enough before it solidifies.

Actually, the gas pressure should have little or no effect. The gas,
in this case compressed shop air, is only serving to cool the torch
tip.

The way the machine operates is that it creates a ~45,000 degree arc
which vaporizes the metal it comes in contact with. The air supply is
simply keeping the torch tip cool or it would burn out instantly.

The reason you have to keep the torch tip in motion all the time is
that once the arc has pierced the material, it is still searching for
the nearest metal to keep the arc going. If you continue to hold it
in one place, that arc starts moving to the side as the hole becomes
larger and this causes that 45,000 degree plasma stream to begin to
come sideways out of the torch tip. This will burn up the tip almost
instantaneously by taking your original round hole and turning it into
a nice sideways slit. There goes $10...

John P.