hvlp question

[stevo wis]

Hope this doesnt sound too dumb, but I cant seem to find an answer.
I have a hvlp accuspray conversion gun that I have set per the instructions and have had good results with it.
It sprays very similarly to other air guns and puts out a fair amount of finish, and as such needs a fair amount of masking for overspray etc.
My question is this: I have seen one demo and another on tv showing a turbine hvlp, which is barely dribbling out paint. It is very low pressure and takes quite a while to paint. Since it is so little coming out, very little masking is needed and it could easily be used to paint a installed door etc.
Should my conversion gun act like the turbine or more like a conventional gun? Im not sure if I am setting it right even though I get good results. I would like to cut down masking if possible and want to learn to do this right in any case.
Any advice would be much appreciated.
thanks,
Stevo

[Loren Hedahl]

Stevo --

You aren't getting any response on this.

But I noticed the same thing. The guys demo-ing their turbine HVLP outfits at at the woodworking show seemed to be able to almost paint a pin stripe thin line.

I don't think they were using paint, but some kind of alcohol based ink.

Loren

[Hal Flynt]

http://www.homesteadfinishing.com/phpBB2/index.php

Best place for Accuspray info.

[Byron Trantham]

Stevo,
I use a compressor for my conversion gun and through experience with the material I use (Target WB spray lacquer) I have virtually no over spray.

The biggest and I think the most important characteristic in spraying is viscosity or how thick the material is relative to the needle size you are using. Viscosity is measured using a Zahn or Ford cup. It measures the amount of time a material flows out of the cup. The shorter the time the smaller the needle. My gun came with a chart that allows me to determine which needle to use. If your material of choice takes too long you need to thin it or get a bigger needle. My stuff needs the biggest needle I have without thinning it. The proper viscosity and air are similar to gas and air in a car. The right mixture runs well, too much gas - rich; too much air - lean. In our world this means atomization or the correct air/material mixture.

The air supply is pretty much irrelevant with the following caveats. The air supply must be dry and provide enough pressure to push the material. I have a small regulator and air gauge at my gun's handle. I have found that adjusting it to 20psi works great. That's 20 psi static. When I pull the trigger, it drops to about 8-10 psi which is about right for an HVLP gun. My compressor has two water separators, one at the tank and one at the hose connect point "down the line". When I finish a session, I always have to drain the separators. A turbine solves all the air supply problems; dry, correct pressure and WARM. Warm air dries the material faster. (In hot weather, that can be a problem though in my case I always spray in doors so the temp is relatively stable.)

The fan size on my gun is not adjustable and I think your Accuspray is. The air horn controls whether it's vertical, horizontal or circular (used for corners). If the air horn ears are perpendicular to the ground the fan is parallel to the ground. If the air horn ears are parallel to the ground, the fan is perpendicular to the ground and last is the air horn ears are set at 45 degrees the pattern is circular. (Note: on my gun, if I use the circular pattern it shoots a BUNCH more material so I have to reduce the air pressure.)

Summary: Your compressor should be fine. Make sure you are spraying material suitable for the needle you are using to ensure proper atomization.

[Phil Phelps]

I own two conversion guns and use then in my business. I have a friend who has a tubine operated Accuspray. I have used his gun and yes, all have over spray. I'm not sure what folks expect from a spray gun. An airless spray gun throws out plenty of over spray. From what I experience, my HVLP has about 80% less over spray than my Binks siphon gun. HVLP's lay out a lot more material than conventional siphon guns. They require more psi from the compressor, about 70-80 psi) and produce about 8-12 psi at the tip. You should also use an inline regulator for best results. I can't see using a gun with no fan adjustment. My gun is a special gun that has a telescopic nozzle and will also spray a circle pattern. You also want wet coats and good overlaps when you spray. There is a whale of a lot of difference when you spray a six inch box as compared to 4x8 panels. If you really thin your material and turn it into an air brush, then yes, you'll not have much over spray. Of course you'll have !#@$%$ spraying a 4x8 panel