Model 3710 Plasma Control Console
Operator’s
Manual
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Issued: 03/11
Page 22
A.
Arc Gas Recommendations
Praxair recommends Argon as the primary arc gas:
1.
Argon is inert, does not react with the powder or substrate and
provides an inert cover for the deposit.
2.
Argon’s arc temperature is high, approximately 20000°K
(35500°F, 19704°C), but an Argon plasma stream or plume has
a low heat content, compared to diatomic gases, e.g., nitro-
gen and hydrogen, thus transferring less heat to the substrate
than other gases, enhancing substrate cooling.
3.
Unlike nitrogen, argon forms no dangerous compounds.
Some circumstances may require adding small percentages of helium or
other secondary gases to the arc gas.
If the plasma does not melt the powder completely, adding a small
percentage of helium or another secondary gas to the primary arc gas
increases the heat level. However, adding these gases WILL CHANGE
OPERATING CHARACTERISTICS.
Consult with your gas supplier to determine appropriate facilities for your
expected spray operations.
Praxair recommends storing pressurized and/or flammable gases in a
separate gas storage facility, isolated from occupied work areas. Gases
should be routed to the spray booth area via “hard plumbed” lines fitted
with appropriate safety devices and shut-off valves. Always follow
national and local regulations and codes for safe storage and handling of
gases.
Gas storage and availability requires serious consideration. Actual usage
depends on specific parameters used, the amount of spraying required, and
overall system efficiency.
