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Building Tips and technical articles. => Paint and finishing => Topic started by: Scott Jenkins on April 14, 2010, 11:45:37 AM

Title: HVLP gun and spraying dope
Post by: Scott Jenkins on April 14, 2010, 11:45:37 AM
Ok, just about ready to put a finish on a model and intend to use a HVLP gun for the first time.
My concern is the gun has a max operating pressure of 43 psi and I am not sure as to whether
I will have to thin down the dope, aerogloss, to get a good flow from the gun. The dope appears
to be quite thin straight from the can. I do plan to experiment prior to putting a finish on the aeroplane
But to be on the safe side I thought I would check in with those who have been there and done that.

Scott
Title: Re: HVLP gun and spraying dope
Post by: Randy Powell on April 14, 2010, 02:26:27 PM
Scott,

It depends on the gun. Needle size (orifice) and pressure along with paint feed make a difference. Take a test panel (I usually use an old paint or fuel can) and put all the adjustments in the middle (air valve half way out, paint fan half way between stops, etc). Set the regulator to the recommended (by paint gun manufacturer) pressure. Put paint in and shoot briefly on the test panel. Adjust the air and paint valves until you get a nice, even spray pattern and the paint is well atomized. If you get the the end of the adjustment and are still getting heavy orange peel (glops of paint), the the paint probably needs to be thinned more. After awhile, you get a feel for this based on experience with the gun. I use a little tool I got from the paint shop. You dip it in the paint and let it drip out and it give you an indication of the viscosity. I know what works well in my gun and so, I thin the paint till I hit the mark.
Title: Re: HVLP gun and spraying dope
Post by: Randy Ryan on April 14, 2010, 07:15:39 PM
"(I usually use an old paint or fuel can)"

Great minds Randy, great minds!
Title: Re: HVLP gun and spraying dope
Post by: Scott Jenkins on April 15, 2010, 11:32:40 AM
Ok, I did'nt really want to say which gun after reading the other paint thread.
Its a Horrible Frieght HVLP Detail gun I did take it apart and check it out the main needle
does have a good fit and a smooth finish and so on. I will take small steps and proceed with caution.

Thanks,

Scott
Title: Re: HVLP gun and spraying dope
Post by: Randy Powell on April 15, 2010, 11:55:26 AM
Scott,

It will probably work fine. My point in the other thread was just that it takes a lot more work and monitoring to get them to consistently work well and they tend to wear out fast. But as noted, they can work fine.