some issues spraying lacquer

[mr_skittle]

This is my first time posting for help in this section, which is good news. It might seem like a bad deal cause I'm having trouble and asking for help, but its great news becuse it means I've finally upgraded to spraying finish with an HVLP setup instead of brushing. I scored this CAPSpray system of craigs list over a year ago for $150. I've only used it once on to spray a utility shelf since then. 

I'm familiar with spraying finish, having worked at a cabinet shop for a couple years and spending plenty of time in the finish room. I've done my fair share of spraying but the equiptment was all different than what I have now.  There was no material pot on the gun at the cab shop. You could spray at any angle and never worry about sputtering air out the gun. With that said, I'm mostly looking for tips and advice with the equipment I have now. 

   

   


On a recent project I gave it another try and tried to spend more time working to get it spraying nice. The project turned out fine but the finishing process could have gone better. The two problems I kept incountering were a sputtering spray and accumulating material on one of the holes in the air cap. Before anyone asks if I had enough material in the cup, of course I did. I'm not sure if the problems are related or not.

[Rob Young]

On my turbine system, if I have the needle/nozzle too large (say 1.5mm when I should be using 1.3mm) AND the material flow adjusted too high I'll get a little piddle and sputter like you describe.  

Mostly just turning down the material flow fixes it for me.  When I clean out the gun, I'll open the flow 100% and I can see two streams.  One of properly atomized water (or whatever I'm using to clean) and a second that sort of sputters out with big sloppy drops.

Even with a four stage turbine, it is possible to have a situation where there is insufficient air to properly atomize the material and you get big droplets which stick to the nozzle instead of becoming small enough to flow properly.

Edit to add, could also be dried finish down inside the air channels of the aircap.  A good soak and clean may be in order.

[jasfrank]

Check your hose that pressurizes the cup. That's really the only thing that has caused those symptoms for me when using my 4 stage. Theres a small orifice where the hose connects to the cup and that can get plugged up. At least there is on my Fuji.