7018 AC will burn fine on DC the pics posted of stick welding with the 200DX was with some old 7018 AC rod i had.
Bottle fill price does vary depending on where you exchange, If i exchange my bottle here at the local farm store it is approx $51.00 w/sales tax for a 122 cu ft argon. If i drive 38 miles to North Kansas City it is $28.80 w/tax
PowerTig 200DX
Supercut 50P
PowerTig Micro 185 SOLD GREAT MACHINE
Millermatic 200
Miller Thunderbolt
Jet 1340 Lathe
Jet 20" Drill Press
Jet 12" Wet Band Saw
Kalamazoo H7 Bandsaw
Forward 12,000 lb 4 Post Lift