Calibrating HVLP sprayer for Cermark

Well, I've been using my little spray gun pretty successfully to apply Cermark to Yeti/Rtic cups for the last year. I had noticed though that the overspray has been pretty excessive and the gun also needed to be cleaned pretty badly, so I decided to take it all apart, clean it, and try to re-calibrate it. I'm sure you can see where this is going...

Now I can't seem to get things back to even the way they were. The pressure doesn't seem to be high enough, or something is clogging, at what I thought were my old settings. And when I open it up with more "paint" volume, it sprays all over the place. So, my questions are two-fold.

First, what pressure do you normally run a 1.00 mm tip hvlp gun at with Cermark? The gun has a regulator and the "manual" (all 1.5 pages) says that the correct range is 49-60 psi. But is that supposed to be the max pressure coming out of the compressor's regulator? Or the pressure the gun's regulator is delivering? It seems like most of the articles I've read say ideal hvlp pressure is only 19-24 psi. Or do guns vary that much? And I'm also confused as to why a gun that has a regulator on it, also has an air adjustment knob on the bottom!?

Second question, is there anything similar in weight and consistency to Cermark that you use to test your settings and calibrate the gun? I've tried just using DNA in the gun and adjusting it while testing on cardboard; but it evaporates extremely quickly and is very hard (impossible) to judge for the correct level of atomization. Would acrylic paint or something like that be similar enough in consistency? Or something else? Just tired of wasting $$$ spraying cermark all over the place trying to get ideal settings locked in once and for all.

I've moved this to the finishing forum where you'll find experts who use spray guns.

I stopped using a spray gun on Yeti's very early on as I felt it was very wasteful. I now use sponge brushes.

what brand of gun is it do you have a viscosity gauge

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Originally Posted by Jerome Stanek

what brand of gun is it do you have a viscosity gauge

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I have the Auropro kit and use the smallest "touch up" spray gun for this which has a 1.0mm tip. And no, I don't have a viscosity gauge.

Would an air brush work a lot more control and smaller container

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Originally Posted by Jerome Stanek

Would an air brush work a lot more control and smaller container

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I don't know. Can you show me an example of what you're thinking of?

some thing like one of these

http://www.ebay.com/itm/New-3-Airbru...il-Art-/390707

I was going to say the same thing. Get a small airbrush. They're cheap, easy to use, can be used with your regular compressor if you can dial the pressure down low enough, and they don't waste much material on small projects. I have one I bought years and years ago, I don't remember the last time I used it, but I know that when I do, it's pretty indispensable.

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Originally Posted by Jerome Stanek

some thing like one of these

http://www.ebay.com/itm/New-3-Airbru...il-Art-/390707

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Might be worth trying. I already have a 60 gallon, plumbed in air compressor though. Is there a version of the smaller air brushes that work with existing air? Or is the whole point that it is a self contained unit?

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Originally Posted by Brian Henderson

I was going to say the same thing. Get a small airbrush. They're cheap, easy to use, can be used with your regular compressor if you can dial the pressure down low enough, and they don't waste much material on small projects. I have one I bought years and years ago, I don't remember the last time I used it, but I know that when I do, it's pretty indispensable.

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Guess that answered my question as I was posting. Is there a specific brand you recommend Brian?

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Originally Posted by Mike Null

I've moved this to the finishing forum where you'll find experts who use spray guns.

I stopped using a spray gun on Yeti's very early on as I felt it was very wasteful. I now use sponge brushes.

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Echo :)

I used to spray everything, including large 24x34" SS operator panels. Really didn't think I was getting all that much overspray until the first time I foam-brushed a panel and found I'd used almost exactly half as much Cermark.

And spraying Cermark at all is an act of futility. First, the solids in the liquid settle immediately and constantly. Whether you're using bottom-bottle hose/venturi feed, or gravity feed, within 20 seconds of starting what's heading to the nozzle is already double the viscosity. I would have shake the bottle at least every 10 seconds. And second, the air used to atomize the spray dries the Cermark almost immediately, so the nozzle is continually closing in on itself.

I made this short video (link below) awhile back, of me foam-brushing five 4" x 6" SS plates with Cermark. It's just that fast & easy on Yeti's too :) --just swipe from top to bottom and rotate the cup for the next swipe. Yeah some will run but it's insignificant, and it's also a good gauge of correct mix-- if it REALLY runs, too thin- if it hardly runs, probably can thin it out some...

In addition to my Cermark dip-jars, have a empty 500gm bottle (several actually) that I keep about 1/3 filled with DNA. When done, I squeeze the excess Cermark out of the brush back into the dip jar. I sandwich the brush between 2 pieces of 1-1/2" x 3" rowmark or SS plates, gets most of it out and it's not all that messy. Then I swish the brush in bottle of DNA and squeeze out the excess. Makes the brush last a long time, and that's the DNA I use to thin my Cermark with- no waste :D --Seriously, once you get used to a foam brush, you'll never look back...

vid> https://www.youtube.com/edit?o=U&video_id=S7gp5Mtk6Oo