Question about my sprayed on finish?

[Deck Reagan]

Hi,
I tried out my HF 43430 hvlp spray gun this weekend. I put on about 4-5 light coats of gloss polycrylic.

It's shiney for the most part but seems to have a very fine egg shell feel to it. It's not as glass like as when I brush it on.

Am I using too much air? Not enough? Not enough material?

I ran it at about 40 pounds of pressure.

Thanks,

deck

[Tom Veatch]

...Am I using too much air? Not enough? Not enough material?

I ran it at about 40 pounds of pressure.


Talking about something I know absolutely nothing about never having used a HVLP system, so factor that into my comment.

40 PSI seems high for a HVLP (High Volume LOW Pressure) system. 40 is about where I set the pressure for my normal (Low Volume, High Pressure ?) siphon feed spray gun. I'd expect to use less pressure on a HVLP setup.

Just out of curiosity, I went here (http://www.hvlp.com/library/docs_open/Instruction%20manual.pdf)to look at the capability of some HVLP turbines. At first glance, it seems like none of them run more than about 8 PSI.

[Mike Goetzke]

I have that gun. I have had good results. I set the pressure at the gun with the trigger fully pulled to around 20-25psi. You may also need to play with the air control valve on the side of the gun.

Mike

[Howard Acheson]

Spray finishing requires as much knowledge and skill as brushing on a finish if you want a good looking finish. In the shop I was involved with, our apprentice finishers spent a week learning about finishes, how to thin them and how to "read" the finish so they could make adjustments. Lots of cardboard boxes were sprayed before they would be able to finish not-critical parts. Generally a few weeks was required before they would be considered fully competent.

I would recommend you purchase Andy Charron's new Spray Finishing. Amazon should have it. This book will tell you about equipment, how to set it up and adjust it and how to "read" the finish to know what needs to be tweaked to get the most out of your equipment.

[Conrad Fiore]

Deck,
Before you go crazy trying to figure out what is wrong with your spray technique, check the material you are spraying. If you used Minwax Polycrylic, check the recommended application methods from the mfr. I do not believe that Minwax is formulated for spray purposes.

[Deck Reagan]

Conrad,
You're probably right but I do know people that have sprayed the minwax with success. It's sort of like Deft brush on laquer. I have great success spraying that material with my siphon gun. I'll keep tweaking it...all else fails I'll brush on the finish coat.

Thanks guys.

deck

[Tony Bilello]

The fine egg shell feel is due to the finish not flowing. Sounds like a thinner problem to me.

Tony B

[Nabil Abdo]

I am new to spray finishing and have been reading Flexner's Understanding Wood finishing.

His Spray gun adjustment procedure:

-adjust pressure regulator to 10psi
-turn control knobs to max trigger depression and fan width
- spray horizontal bursts on cardboard

increasing the air pressure 5psi until you get an oval shaped pattern where the runs are equal across the width

its gonna depend on what you are spraying ie viscosity and the gun in question.

i have yet to get the even film laydown I am looking for.

highly rec the flexner book though,