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General AirBrush Questions
3 replies to this topic
Posted 24 January 2007 - 12:13 AM
I have a Paache VLS and I have a few general questions I'm hoping someone can help me with. I'm brand new to this but I have been playing with it for a day or so. My main question is about the adjustment of the needle adjusting sleeve and if this adjustment will affect how much paint comes out or the pressure at the tip. Is there a correct way to determine how to adjust this item. My compressor is putting out about 40 psi. How are you guys regulating the pressure back if you want to paint at a lower pressure. Is it done with a air regulator or with the gun. thanks
Posted 25 January 2007 - 08:42 AM
I don't have that exact gun but I regulate the pressure at the compressor. Mine has a regulator built in and I can adjust as I go. It may not be correct but that works for me.
Posted 25 January 2007 - 02:17 PM
Pressure should be regulated first by a regulator, frequently built into a moisture trap. The trap and the ability to adjust psi is critical for the Paasche brushes.
The VL is dual action so you then further regulate pressure with the trigger. Needle sleeve is basically an adjustment for paint (although that will obviously impact your shooting pressures). I would leave it alone.
Posted 25 January 2007 - 09:32 PM
I don't have the same airbrush but most work on the same principle I believe and I think I get where you are coming from here. All the needle does is regulate how much paint and air is expelled and atomised from the nozzle, the pressure remains the same, if you connected a pressure gauge at the nozzle and opened the needle the inlet and outlet pressure would be the same regardless of the position of the needle hence the ability to have a high pressure with a very low flow rate, the needle only restricts flow rate not pressure. An example may be the tyre pressure on your car, the pressure you measure with your gauge at the shraeder valve is the same pressure as inside the tyre even though you are measuring through a tiny valve, if we were able to regulate pressure simply by closing the needle then regulators would not be required . The compressor I use has the regulator at the compressor and I set the pressure with the airbrush open not closed eg I do not set a static pressure. I am basing my reply on my experience in the gas and water industry and the principles are going to be the same after all air is just another gas .