Spraying water based poly

[lrogers]

Hey guys! I'm working on a set of ballet bars for the dance studio my daughter-in-law is opening. I want to use water base poly for the top coat and try out the new HVLP spray gun I recently got. Any tips for this? Viscosity numbers for thinning? Pressure at the gun nozzle?

Any and all suggestions are greatfully accepted!!

[cabinetman]

Without knowing what gun, tips, or which WB poly, I would start with a normal aperture (could be 1.4), and approximately 50 PSI from the tank, and approximately 10 PSI at the gun. Use some cardboard as a test sample. Most poly's can be thinned 10%. So, it's easy to spray. Practice with distance from the subject, path movement speed, air pressures, fluid control, and pattern.

.

[Mr__Bill]

Bare in mind that as you thin the poly it tends to run easier and faster. The trick is to find the thin point, air pressure, needle valve setting and distance from work to spray. Changes in temperature will change one of the above, perhaps two or more. Never did figure out just what but as the sun went down and the temp dropped my spray job went to Hades. Good luck with yours



Bill
over here on the left coast

[lrogers]

Guess a few more details would have been better! The gun is the small gun that Harbor Freight sells (two gun kit). It has a 1mm tip and I'll be using the Minwax Polycrylic water born poly. The bars are 1 17/8" dia. oak stained with Minwax English Chestnut.
I can control the the temp/humidity in the shop. never have been much of a painter, but I have a BIG project I hope to be starting in the not too distant future that will require a good bit of painting so it's time to start now and get some practice.

[cabinetman]

I would experiment with that tip. If you're using the detail gun you may have to lower operating PSI. If the gun doesn't have it's own air gauge, put one on. No need to worry about humidity, or temperature this time of the year. WB isn't affected by humidity. If you're using a fairly narrow pattern, try to only apply light coats, and spray items vertically if possible to prevent pooling.

.

[JimD]

I have sprayed PolyCrylic but it wasn't easy. My impression is it is purposely made somewhat thick for brushing. I ended up rolling it on a large project after trying spraying with a Wagner conversion gun. I eventually gave up on the Wagner, bit the bullet, and bought a Fuji Mini-Max 3. I wish I'd gotten it sooner. I have not tried anything but Resisthane yet but I do not need to thin at all. From the reviews I've read I should not need to. I can throw a 14 inch or wider pattern (but it empties the cup in less than 10 minutes if I do). I normally adjust back down to about a 6 inch pattern. This is a turbine based system. It atomizes the finish MUCH better making a quality result MUCH more likely (at least for me).

I think you will want a larger needle set if you can get it.

Jim

[lrogers]

Thanks for the input fellows. The job I was doing got cancelled, but there is another in the works that I can try this out on.

[cabinetman]

Thanks for the input fellows. The job I was doing got cancelled, but there is another in the works that I can try this out on.

Well, that's bad news about cancellation, but it will give you a chance to experiment and practice.

.

[lrogers]

As you well know, when you have a shop you never lack for projects! There's a rocking duck under construction now, two rocking dalmations, a turtle maze and and several jewelry boxes waiting in the wings. I also have two gallons of paint waiting to go in the walls and epoxy coating for the floors. Oh yeah, and once my siblings and I sell the house my dad left us, I'll be building an ultra-light! No great lose about the ballet bars!