Percolating!

As far as I know It is only appropriate for gravity feed guns. Since i was using my only hvlp gravity feed (a touchup gun) today I tried the procedure out to see for myself.

It involves reducing the gun inlet pressure to about 5 psig, loosening the air cap at least a couple of turns and pulling the trigger. This is oviously after you put in a small amount of gun cleaner in the cup. What I did was to dump out any excess paint in the cup and swab out as much residue as possible with a paper towel, then put in a little gun cleaner. When you do this no material will come out through the nozzle. Instead, air and gun cleaner will "percolate" through the gun passages and bubble up in the cup. The cleaner in the cup is essentially recirculated through the gun passages and you can see it pick up more and more of the color as time goes by. Caution: don't put your face over the cup while you are pulling the trigger. The bubbling in the cup is fairly violent and if the pressure is high enough you could be splattered in the face and eyes. Such an act would qualify you for a Darwin award, similar to one given to people who use their fingers to clean the discharge chute of a running lawn mower...you are asking for it.

While I would still disassemble a gun for a final cleaning before putting it away, the percolating procedure seems to work pretty good. It will likely save gun cleaner over just blowing a bunch through the gun several times in a more typical fashion. I've only done it in going from color to clear. I couldn't detect any residual color in the first shot of clear out the gun. I suspect it would work just as well in going from primer to color. I'll try that the next time I use that gun for primer and color in the same day.

Anyone else try this? Comments on it?

Rod