HVLP spary gun question

[cbargs]

Hello Prop Gods,
I use smooth cast 300 to spray paint stormtrooper helmets. Right now I use rattle spray paint cans and I am ridiculously fed up with those blasted things. Something always goes wrong and they are very unpredictable now matter how many proper steps I use. I'm looking into using a HVLP spray gun to paint my urethane plastic helmets. Any suggestions on what kind of paint and any tips will be greatly appreciated. Thanks again for all you guys do!

 

[Killtime]

I can offer a few pointers, I hope it's not information you already know!

Find the thinning agent for your paint of choice (Turpentine, metholated spirits, water ect ect) and always thin out your pots, just a little to keep viscosity down for smooth finishes. Be fastidious with flushing/cleaning your gear with said thinners after use.

Use a decent volume air compressor with at least two water traps, one on the reciever and one outlet to your hose should keep moisture out of your supply of air.

 

[DrewSmith007]

http://www.harborfreight.com/high-volume-low-pressure-spray-gun-kit-44677.html

I picked up one of these a couple months ago. I havn't got to play with it much, but the bit of thinned down latex I sprayed went down really well. If you don't have a large-ish compressor and don't want to get one, this is a reasonable alternative. One word of caution though, it's very loud. It's basically a reverse vacuum cleaner with a paint gun on the end.

If you go for it, make sure you get a 20% off coupon, they're all over the place!

 

[Alpha Proto]

I read on this forum that if you keep your rattle cans in slightly warm water before use they flow better.

 

[The Ronin]

I read on this forum that if you keep your rattle cans in slightly warm water before use they flow better.

Yup, a warm can = better atomization of the paint.

HVLP guns are still better, and you don't need a giant compressor to run one. I use mine on a little twin tank, and 40-45 psi seems to be the sweet spot to get it spraying beautifully.

You can get inexpensive automotive lacquers by the quart at most auto parts stores. They're usually good enough for most props, but can still be a bit on the soft side. That's what I use in most cases. If you want really good paint then you need to step up to a 2 stage urethane paint that requires mixing color+reduce+hardener, but that stuff gets expensive quick.

Pay attention to the pressure and the gun settings. It can take a little trial and error for each paint to get things shooting perfectly. I've had 3 different colors from the same brand need different pressure and gun adjustments.

 

[cbargs]

ThAnk you all for your input. However I do have my spray paint cans take a hot bath before using them and I still get "orange peal " and "fish eyes". I don't know if it's just the plastic I am using. I sand it down with 220 before painting and wipe it off with a tack cloth and I get the same results.

What kind of paint do I need to get to paint smoothcast 300 with a hvlp gun and where can I get it? Thank you all once again.

 

[batguy]

I've always had decent luck with spray cans when they are used right. The finish isn't perfect, but it usually isn't perfect coming out of the gun with "real" paint either. Wet-sanding & buffing the paint is part of the job. With mass-produced stuff in factories they often bake their finishes to perfection.

I hate using lacquer for much of anything bigger than a little plastic model because the durability is zilch. I wouldn't use it for the primary color coat on a costume helmet.

 

[The Ronin]

ThAnk you all for your input. However I do have my spray paint cans take a hot bath before using them and I still get "orange peal " and "fish eyes". I don't know if it's just the plastic I am using. I sand it down with 220 before painting and wipe it off with a tack cloth and I get the same results.

Orange peel is something you just have to learn to deal with. It's mostly a matter of technique learning to get just the right amount of overlap on passes and such. Even high end cars have orange peel coming out of the spray booth. It's why there are high end polishing systems that take the high spots down and polish everything shiny and smooth.

Fish eyes mean that you have some kind of oil on the surface that is preventing the paint from sticking. Try wiping the surface down with some acetone on a clean, lint-free cloth.

 

[cbargs]

That makes me feel a little bit better Ronin. I forgot to mention once I remove my cast from my mold I give it a light sand with 220 grit and give it a soap scrub with dawn dish soap. I then rinse and let it dry for a day. Is there still soap residue I may be missing? Do I really need to use a soap scrub if I just wipe it down with acetone?

Then another question dawned on me. How much time does smoothcast 300 need to cure. I heard that while it cures it can release oils. I let it cure for a hour in the mold and then start my paint prep process right after that.

 

[The Ronin]

An hour? That seems like way too short of a cure time to me. I haven't used 300 yet, but I usually follow a 24-48 hour minimum rule for things to cure and degass.