[TheForge] Question about MIG welding, spray deposition?

[Peter Fels & Phoebe Palmer]

Been trying to figure out MIG spray deposition now that i have the power 
to do it.
Using .035 wire and argon75% CO2 25% mix gas. Electrode negative.
If i crank it up to about 400 ipm and about 25 volts i get spray 
deposition as i imagine it to be, but the nozzle and contact tip seem to 
foul pretty quickly.
Part of the problem was the awkward position  of the welds and a sore 
back...which contributed to the fouling i'm sure.
Looking on the web, they were talking about a different gas mix ( i was 
using what i have and can easily get) and electrode positive setting.
Is that right? I keep imagining the wire fusing to the contact tip as 
soon as the trigger is pulled with electrode pos.
Can the gas  i have be made to do spray deposition decently?
Sure appreciate having you folks around to straighten my path every now 
and then...pete f