Can a PC HVLP gun die?

[Charlie Plesums]

I have been happily using the Porter Cable PSH1 conversion HVLP spray gun for a couple years - exclusively with lacquer - happy until recently.

A couple weeks ago, the gun started spitting rather than spraying...not a very even distribution, with pretty gross droplets...definitely not a fine mist. One suggestion was that I hand't mixed the satin lacquer well enough, so it needed filtering. So I have cleaned the gun every which way, multiple times, including disassembly. Soaked the nozzle and needle valve in solvent. Run fine wires through all 14 air nozzles, plus cleaned the air gap around the needle valve. Multiple times.

I have only sprayed gloss (no sediment) since the problem started. Spraying pure lacquer thinner, the best I seem to be able to do is get a "figure 8" fan... much more at the two sides than in the middle. To me that suggests that the air isn't coming out around the needle valve right, but I have double cleaned and checked that area.

Overall I have probably sprayed 50 gallons of lacquer with the gun (not counting the gallons of thinner), most of it gloss (no sediment). Could it be worn out? Any suggestions besides "clean it again?"

[tod evans]

charlie, take the cap off your paint reservoir and try the gun, many times the breather hole will become plugged with crud. if that doesn`t help crank up the pressure and see what it behaves like. if still no change soak it overnight in thinner then crank up the air and try again.....still no luck...they`re not real expensive and only worth so many hours to fix...02 tod

[Steve Clardy]

Charlie. Did you oil the needle where it goes through the trigger support? The brass one. They get dry, and stick there, not letting the spring on the rear do its job.
Either that or your regulator has passed out. No pressure.
I run mine at 20#
I have three, about 3-4 years old, all of them.

[Charlie Plesums]

Thanks for the suggestions.

Tod, I am an expert at plugging the breather hole, so I often check... not this time.

With no air pressure, the flow rate from the nozzle was normal, stopping and starting as expected. (I check that rate rather than use a viscosity cup, every time I fill the gun)

Steve, I had forgotten about oiling the brass seal at the trigger... will do, but the flow is stopping and starting normally.

After the last of many cleanings I left lacquer thinner in the gun, and left the gun at the shop entrance where I spray. We are having a heat wave, so the gun got sun-baked (probably 120 degrees or more) with the thinner in it. I was so frustrated I let it bake another day... and now it works fine again. So my recipe if anyone has this problem... clean thoroughly, cuss a lot, post a request for help, bake at 120 degrees for 36 hours with lacquer thinner in the gun, and serve.

Steve, I am glad to hear you run it at 20 psi on the local regulator. The book said 10, but that didn't work worth a darn, so I have been using 20 since the beginning. Next time I clean it I may try higher air pressure to see if I can reduce the baking cycle! (I didn't think of that option)

Thanks for your help

[tod evans]

charlie, i`ve let lacquer set up to the sludge state in guns before, i just drop the gun in a bucket of thinner and clean it the next day. as far as pressure goes i never rely on a gauge, start low and crank it up untill you get good atomization with minimal blowback off the work and off you go. glad you got yours fixed...02 tod

[Steve Clardy]

After the last of many cleanings I left lacquer thinner in the gun, and left the gun at the shop entrance where I spray. We are having a heat wave, so the gun got sun-baked (probably 120 degrees or more) with the thinner in it. I was so frustrated I let it bake another day... and now it works fine again. So my recipe if anyone has this problem... clean thoroughly, cuss a lot, post a request for help, bake at 120 degrees for 36 hours with lacquer thinner in the gun, and serve.



Good recipe!!!! Lol