First of all I think you got a good deal on the price.
My badger just runs continously. If I am not using the airbrush, there must be an escape valve so excess air pressure is vented to the atmosphere. Otherwise it would sieze up or explode. The Iwata detects maximum pressure and turns itself off if the airbrush is not in use.
Their method of pressure regulation is to create a leak, that matches the output of the compressor to create the desired pressure.
There is no reservoir according the their specs. I cannot find a cut away view of any airbrush compressor.
What we know: There is a motor. There must be piston to compress the air. Beyond that, there must be some sort of chamber, otherwise the output would be pulsatile. All that has to fit into “under the hood” of the air compressor.
How big can that chamber be in a compressor that size? We know the size of a standard plastic bottle of water. Is there room for that? I don’t know, but let’s say there is: a pint,16 oz. In a pancake compressor, you see the chamber, in my case it’s 6 gallons or 48 pints.
Picking numbers out of my head, you turn the compressor on and it pressurizes to whatever it’s limit is, say 40 psi, and turns off. The add-on regulator will dispense air at a fixed pressure, say 20 psi.
Volume and pressure and directly related. Pull the trigger on the airbrush and the pressure in that chamber is going to fall much faster than the pancake. If the chamber is 16 oz, and you shoot 4 oz, you have lost 25% of the volume and 25% of the pressure.
Only Iwata knows what automatic means and what pressure drop will turn on the compressor. Is it 38 psi, 30 psi or 20 psi? I have no idea. The smaller that chamber really is, the bigger percentage drop in both pressure and volume.
It was hyperbole to say you compressor will never turn
