simple spray recomendations for two part polyurethanes over epoxy

[daniel coyle]

Hello
I have been using a gravity/cup gun to spray waterbased System Three WR LPU (Linear Polyurethane - 2 part) onto a complex curve product I make and seal with several coats of WEST SYSTEM clear coat epoxy (hardener 207) I have tried a few different nozzle sizes, most recently a 1.0 while diluting this product about 25% (as recommended by the manufacturer). The guy who runs the cabinetry shop where I apply this stuff has the same opinion (very hard to apply correctly but a very awesome finish material) The product gives an amazing, durable finish but is near impossible to apply without runs or other imperfections. I am pretty much done trying to make it work but it anyone here has experience with it or anything like it and has a silver bullet I would love to hear it.
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So, I am now going to experiment with an acrylic polyurethane 2 part product called ACRYLIC POLY UV PLUS. The data sheet viscosityacrylic poly uv plus data sheet.pdf does not give a viscosity. I am told this product is similar to what auto finishers use. I would like to use a cup/gravity gun to apply this stuff. is there something that would be better (hoping not to buy more spray equipment)?. Can anyone recommend anything? I am looking for the correct nozzle size and pressure (if applicable). I also am looking for ways to figure out what the viscosity is. The manufacturer does not provide a recommendation for application other than "Conventional, airless spray, brush or roller". My hope is that this stuff, being thinner than the waterbased stuff, will apply more easily.

[Mike Hollingsworth]

Spray Paint 101:
Thin first coat. Don't try to get that glossy coat. Let the first coat set up and get sticky. It should hold the 2nd heavier coat.

[Jamie Buxton]

Read up on the health hazards of isocynanates, the major ingredient in the catalyst for that finish.

[daniel coyle]

Thanks for the replies. Mike, the product I was using was a glossy finish product. I have tried spraying it on thin with inconsistent results and too much time put in experimenting. Jamie, I would love to keep using the water based stuff as it is less toxic but it isn't working. Do you have any suggestions?

[David Hawxhurst]

you'll most certainly need a viscosity cup so you can determine the proper cap and needle to use. as for staying waterborne every major manufacture makes it, just a matter of figuring out who's you want to use. is there any reason not to change to another type of finish? are you set on using only poly? would a conversion vanish or 2k urethane work?

when i was messing around with waterborne stuff a few years ago i just could get the results i was looking for from what i was using/trying. many improvement to waterborne finishes have taken place since i switch back to solvent based finishes, but the cost of most of them that would probably work in the same or more than the solvent stuff. i have the proper personal protection equipment for solvent based.

[Mike Hollis]

I'm definitely no expert on finishing, but what is the piece depicted in the photo - equestrian helmet? Amazing workmanship and I'd love to know how you did it.