View Full Version : Air brush compressor advice

Jerry Allen
05-09-2006, 7:02 PM
Here's some advice if you are using a Harbor Freight air brush compressor with a guage or anything similar.
I had been using one for over a year for air assist. I had it set at 18 lbs. according to the guage on the compressor and it worked okay for all that time. You could hear the hiss at the laser head. The pressure is adjusted using the valve at the inlet to the laser, after the guage.
Recently I decided to jack up the pressure to max, about 40psi at the guage. I should have picked up on it, since there was no hiss at the laser head. After working the better part of the day I started hearing strange noises and then the compressor seized.
I thought that was it and that I would have to buy a new compressor, but it started working again after it cooled down.
The guage is now set at less than 5 lbs and it is working way better at controlling flames, etc., than it did at 18psi.
The moral--the guage is reading the pressure at the pump, not at the laser head. Max pressure at the guage means the air flow to the laser is OFF.

Jim A. Walters
05-10-2006, 5:13 PM
I think the issue here is pressure vs. flow. Pressure buildup is resistance to flow. If there is no pressure, the pump is pushing all the air it can out the nozzle. If there is pressure, there is resistance to flow, and you will tax the compressor.

If the substrate I am lasering won't move (heavy), I will open the valve wide open. It's another story when you are trying to cut LaserThins!

Joe Pelonio
05-10-2006, 5:58 PM
Since it was designed to use such air pumps that's why the Epilog (and others?) were designed with a cutout, so that if the pump is on but air is not called for on that job the air is released inside the bottom of the case, to stop the pump backup/overheating.

When set for air on vector only, and I send a combo rastor/vector job, the
air is releasing and the gauge shows 1-2 lbs. When it starts to cut the air goes to the beam head air tube and the gauge shows 25 lbs, which is why I set it while cutting.