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Pressure for HVLP Gun

2445 Views 3 Replies 4 Participants Last post by  302 Z28
I was wondering what do you guys run your HVLP guns at pressure wise(PSI)? I sprayed epoxy primer at 25psi at the regulator/filter and it came out great. I have an 80 gallon compressor. But a friend of mine ran his gun at 12psi and it came out with horrible with real bad orange peel, so much that we wet sanded it with 320 to try to break it down quick and by the time it was smooth(still had tiny peel in it) it was so thin that metal was visible ever where!!! I know that seems gritty but it felt like it was textured spatter paint, lol. I don't run high compression fittings or anything special just the standard stuff and don't have any problems but I was wondering what you guys ran for primer, metallic and clear? I have never spryed High Solids Clear before. I use a 1.4 tip to spray all coats. Just for HVLP guns.
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They are all different.
Set it at what the mfg recommends.
I have HVLP guns that use as low as 16 psi and others that
use 45 psi.
Most all are converted to 12 psi at the tip, but the inlet pressure
to get that varies by mfg.
I don't know any that have inlet psi that low:pimp:
As stated, it varies by manufacturer and then it may have to be adjusted to tip being used as that adds another variable to the process if you have a gun with multiple tips.

Here’s something that may interest you and others who also may be reading. A friend of mine where I just started working for part-time was priming a truck using Dupont 6001S. I noticed the texture was that of cottage cheese and I mentioned it shouldn’t go on like that. He thought that was normal application. I informed him it wasn’t.

So, he handed me the gun and said, “Here, show me how it should look.” I took the gun and squeezed the trigger once just to check spray pattern and trigger action, and without making any adjustments to the gun I let instinct take over. I began laying the primer on the fender and we could see the fresh coat laying over the cottage cheese smoothing it over like it’s suppose to look.

He wanted to know what I was doing different to get that finish. I have nearly 40 years experience spaying. You name it; I’ve sprayed it more than once. When he sprayed he held the gun too far away allowing the primer to partially air dry before reaching the surface producing that rough texture. Moreover, he was moving his gun too fast accelerating the drying before application.

More often than not it’s not the product or the adjustments that produce a good or poor finish it’s the painter himself.
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There is no set pressure that you can dial in that will be right, it all depends on the material your moving and several other factors. The purple HF guns I used on my 34 were set at 35 psi for the base and cranked up to 45-50psi for the clear.

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