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11-18-2011, 11:22 PM #1
OT - HVLP tip size for thick paint?
I don't currently have a spray gun and for several reasons have been planning to get a 4-stage HVLP turbine system. My intention is to paint the next large machine with Sherwin-Williams B66 Pro-Cryl primer and B73 zero VOC waterborne epoxy. Both are "reasonably" viscous paints but the S-W datasheets for these products don't give specific viscosity (ranges). I have first hand experience with brushing the Pro-Cryl, but not the epoxy. The datasheets do have some recommendations for airless sprayers and conventional sprayers, but not HVLP.
Epoxy recommendations:Airless: .015-.017 tip at 2000PSI
Conventional: DeVilbiss MBC-501 with tip E and nozzle 704.
Primer recommendations:Airless: .015-.019 tip at 2000PSI
Conventional: Binks 95 with fluid nozzle 66 and air nozzle 63PB
The HVLP system I am considering offers needles/caps in a wide range of sizes.0.7mm .028"I'm confident the 1.4mm cap is the smallest I should be considering for this stuff, but I don't know how large to go. 2.3mm has been recommended for "texture paint" which seems too thick, but also for "industrial primer" with, of course, no indication of how thick that is. All three of the 1.4, 1.8 and 2.2mm tips are recommended for "latex", substantially thinned for the 1.4mm tip.
If you can convert from the airless or conventional recommendations into the HVLP world, I'd appreciate the benefit of your experience. I'd also like to know how much two adjacent tip sizes will overlap in the paints/viscosities they will handle.
11-19-2011, 07:27 AM #2
I would bet that you would have to thin it to much or run it with a pressure pot to run it. Over the years I have become not a fan of HVLP. But Of thinking of Garco new Cup Airless set up . Like this one. Photo Gallery
they have a couple of models. They have gotten good reveiws for may painting forams and would be cheaper that a good HVLP. Not anything like the old Warner busebox sparyer
David"s Painting and Wallcover
11-19-2011, 09:27 AM #3
1.4 tips are commonly used for spraying automotive base and clear urethanes. These paints will typically be less viscous than industrial paints by a wide margin.
2 component automotive primers are in the viscosity range of industrial paints. People typically shoot them with a 1.8 to 2.3 tip. The tip you'd want to use on these would be dependent on how you typically handle a spray gun. If you move fast and control film thickness by the speed of the gun, the 2.2 is preferrable, but if you want to handle the gun more like a detail gun then the 1.8 would be better. Personally, a 1.8 with thick paint drives me nuts, but suits some people fine.
11-20-2011, 10:14 AM #4
I have a 3 stage HVLP. For what its worth, latex enamel has to be thinned quite a bit to spray with my set up. (woodworking application) Imagine adding 1 oz. of water to 8 oz. of paint. Typical industrial enamels like Rustoleum need thinning as well, but not so much.
Sorry for no specific advice, but if your material is thicker than interior latex enamel you probably can't spray it with typical 4 stage HVLP. To stay with HVLP you will have to go up to some pretty expensive industrial units.
And you probably already know this, but any epoxy is --extremely dangerous-- to breath any airborne particles in even the tiniest amount. Use full suit and 100% fresh air mask or don't spray it.
11-20-2011, 04:50 PM #5
I believe the problem with the 2K paints isn't the fact that they are 2 pack, or epoxy per se, it's the isocyanates 2K paints traditionally contain. By the same token, other paints MAY contain isocyanates and therefore require the same precautions. For example I add isocyanate to some paints (sold as a hardener). Having said that, I believe the new generation of 2K paints coming out now are much safer in that regard, so check with the paint manufacturer. I've generally found them very forthcoming with information, and will be able to guide you on the best guns/tips to use. Sorry I'm really not that familiar with the latest paints as I haven't been keeping up with developments. I'm interested in hearing from others regarding these paints as I don't like isocyanates. Here's a little primer to whet your appetite as to why. MVR Case studies - Painting and isocyanates
The "industrial primer" probably means high build primer, and yes that will need a large tip.