Post-Cat Material Flow Issues

Fluid temperature and tip size can make all the difference. September 16, 2008

I attempted to spray some furniture with black tinted MLC Agualente Post Cat Water-base lacquer. I am using a Devilbiss GTI600G Gravidy feed gun with a 1.4 tip and a 100 Air Cap. My air supply is set to 30PSI.

I can't seem to get enough material flow. The lacquer does not require thinning as per the manufacture. I have to move the gun too slow which is resulting in sagging. Does anyone have any suggestions?

Forum Responses
(Finishing Forum)
From contributor R:
This product seems to work best in a HVLP gun with a 1.6 to 1.7 tip fitted with the corresponding air cap. Apply light (2-3 wet mil) coats and you should get a decent dry time with no cloudiness on dark woods.

From contributor P:
You can thin the finish with distilled water Ivan (e.g., 5%). That will help the flow and atomization. You can also heat it to around 85 degrees Fahrenheit which will also reduce its viscosity and make it easier to spray.

From contributor A:
1.4 n/n set is way too small for Agualente. We typically use 1.7 n/n on the gravity and 1.5 n/n on the pressure gun.

From contributor D:
You are fortunate. The GTI has a common needed and aircap for a large variety of nozzle sizes. For $35 you can get the correct nozzle and change nothing else and be good to go. It sure doesn't work this way with SATA.

From contributor L:
I have sprayed this varnish with a 1.3 n/n setup without problems. I will say though that I warmed up the varnish first because it was cold in the shop, so I am sure that helped.

From the original questioner:
On my original post I had made an error. I actually was using a 1.6 tip. I ended up just warming up the finish to 85 degrees F as suggested. This seemed to make a world of difference. I used a digital thermometer and did not realize how cold my finish was sitting on the floor.

In addition I also found I had to use the course paint filter that is installed in the gun (using the Devilbiss DECUPS system). The fine filter still would not allow maximum flow through even with the finish heated. I also noticed that warming up the spray booth to about 80 really speed up the drying time.

This water-based finish is the way to go. Finish cured hard was smooth as silk. Clean up was easy and no headaches.