I have a Parker 12 volt dc air solenoid I had laying around that is controlled by pin 14. I have the output of my oxygen regulator T'd off, one side goes to the preheat oxygen side of my machine torch, the other side goes to that solenoid, then to the cutting oxygen port of the machine torch. These 12 volt valves and others like them are available for around 20-30 bucks. The Hobbycnc board has a solder terminal point for pin 14, I believe. This will need to be connected to a relay for the solenoid. A 110 volt AC version of these valves are available as well. If you need one of the solenoids, PM me.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
"If the women don't find you handsome, they should at least find you handy"
-RedGreen show.