Hvlp Spray Gun And Por15

[Bornindesert]

Last weekend I shot some POR Chassis paint on the underside of the Comanche Bed.

I used a Sata HVLP spray gun with a 1.7 nozzle, 40-50psi at the gun and good clean dry filtered air. Ambient temp around 80F, negligible humidity. This is probably the third or forth time I've used this gun, so still gaining experience with it.

The paint went on pretty dry, with some spatter texturing. It was hard to get it to lay down without really slowing up the pattern. I'm no expert when it comes to figuring out why it sprayed so dry, so figured I'd throw it out there for some feedback or suggestions.

The prep...

Laid down the entire quart, well mixed and no thinner.


Was it the tip size, material too thick, too warm out or too dry as in relative humidity?

I'm not worried about the coverage as its on the bottom but would like to understand what can cause poor flow in what I'd consider pretty good conditions.

[mnkyboy]

Probably too much air pressure. Is that gun even rated to be ran that high?

 

I would have reduced the paint and cut the air pressure by about half.

[mnkyboy]

The nozzle should have been fine, a 1.7 is usually used for primer so it should shoot fine.

 

I use a 1.7 as a primer gun, my main paint gun is a 1.3, and I have a 1.0 for touch up.

[GirsMJ86]

They recommend only using 25-35 lbs for that stuff.

 

http://www.por15.com/Data%20Sheets/chassiscoat%20directions.pdf

 

It doesn't mention nozzle size, but it does say it should be thinned 10-20%. I've never sprayed a por15 product so I can't comment from personal experience. I've always brushed the stuff and it levels out nicely without issue or strokes being noticeable.

 

The stuff is the same viscosity as normal por15, and it says to use their por solvent stuff to thin with. Could be a marketing ploy, but because of the properties of the stuff normal thinner might screw up the adherence, dry time, or who knows what else. Just my

[terrawombat]

I'm not paint expert, but I do know that POR-15 is some THICK stuff.  Most of the paint I've sprayed that has gone on smooth is far less viscous than POR-15.  Like mnkyboy said, I would have reduced the paint by adding a thinner to it.

[Bornindesert]

Thanks Mnkyboy - I'll be spraying epoxy primer next and will reduce the paint, add the hardener and drop the pressure like you suggested. The guy at the paint store told me to shoot the Chassis POR straight out the can. Lesson learned!

[Bornindesert]

I'm not paint expert, but I do know that POR-15 is some THICK stuff. Most of the paint I've sprayed that has gone on smooth is far less viscous than POR-15. Like mnkyboy said, I would have reduced the paint by adding a thinner to it.

The POR calls for POR reducer which I didn't have, and clean up with Lacquer thinner which I did have. I didn't want to chance it but probably could have reduced it with the lacquer thinner and have been fine. The paint wasn't super thick, but probably more viscous then I'm used too - thanks!