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Aaron Koehl
07-23-2008, 10:22 PM
Any painting tips for painting a large area of white acrylic sheet?

I tested an area tonight using Valspar Plastic Paint and some letters made with vinyl stencil mask. The mask worked great--the paint did not bleed underneath the mask at all, the mask peeled readily within minutes of painting, and the edges were clean, without pulling any paint from the edges.

I am a little nervous at my spraypainting ability on a large area, however, and could use some advice. I wonder if I should use a spray gun instead for a wider spray beam. I am confident spray painting smaller parts and letters with a can, but I am not sure how I can ensure even coverage on an 18" x 96" solid area.

The extra caveat is that the sign is back lit. Hopefully the paint will be thin enough that some of the color (royal blue) will come through. (Of course, the masked areas will show white).

Thoughts?

Joe Pelonio
07-23-2008, 11:29 PM
It's really hard to get even coverage with rattle cans on such a large sheet. Typically, there will be heavy and light spots because the tip has a narrow spray pattern. I noticed the other day that a can of Rustoleum had more of a sprayer-like pattern, vertical and close to a foot high. You may want to read the cans and try to find one that's better suited but still "for plastic." With a gun, I have used automotive primer first, then used exterior latex. For this job you may want to experiment or test first on scraps.

James Stokes
07-24-2008, 4:50 AM
For large sheets of acrylic I use a foam roller and latex paint.

Aaron Koehl
07-24-2008, 10:45 AM
For large sheets of acrylic I use a foam roller and latex paint.

James,

Thanks, I never thought of using Latex. I had just assumed it would blister and peel under the heat. It's going inside of a metal lightbox, behind a plexiglass face, and is in nearly direct sunlight most of the day.


It's really hard to get even coverage with rattle cans on such a large sheet. Typically, there will be heavy and light spots because the tip has a narrow spray pattern. I noticed the other day that a can of Rustoleum had more of a sprayer-like pattern, vertical and close to a foot high. You may want to read the cans and try to find one that's better suited but still "for plastic." With a gun, I have used automotive primer first, then used exterior latex. For this job you may want to experiment or test first on scraps.

Thanks Joe. I think I will head to the hardware store today and investigate some other paint cans.

Scott Shepherd
07-24-2008, 12:42 PM
Aaron, I know it's probably not what you want to hear, but for that application in direct sunlight in a lightbox, I'd start looking more at something like a Matthews Paint product. Available from N.Glantz in your neck of the woods. Not an easy to use product, but it's got superior life and color retention.

James Stokes
07-24-2008, 1:07 PM
Actually what I use is an acrylic latex exterior paint. But the foam roller is really what I was posting about.

Joe Pelonio
07-24-2008, 1:20 PM
Perhaps I should have mentioned this sooner, but for this kind of work I always use plotter cut translucent vinyl film. For those with a plotter it's a lot faster than painting, lasts for years and can take the sun.

Scott Shepherd
07-24-2008, 1:31 PM
Good point Joe. Aaron, if you guys don't have a plotter, and want to come here to do it, let me know. You can come cut it for free. Or you can ship me the vinyl, and I'll cut it and ship it to you, no charge for my cutting.

Aaron Koehl
07-24-2008, 2:08 PM
Good points all.

I called N. Glantz today and had a nice conversation about painting acrylic. I plan to go down there tomorrow to pick up some paint- she told me the Matthews was for aluminum, but they carried a variety of paints specifically for spraying plastic.

The nice thing about N Glantz is they seem to have good pricing and deliver daily. Unfortunately, I'm 20 minutes outside of their delivery loop, so I'll have to make the 50 minute drive down there tomorrow.

I've already cut the translucent vinyl mask on the plotter so I am good to go there (Oracal stencil mask). I would have done the whole thing in vinyl except, again, I was worried about the sun's effects on such a large piece of vinyl. So, I settled on a vinyl mask, and paint.

I'll let you guys know tomorrow how it goes down at N Glantz Sign Supply. I might pick up a roll of vinyl if I can be convinced that such a large piece would hold up in the hotbox.

Scott Shepherd
07-24-2008, 2:48 PM
Matthews Paint makes one of the best acrylic paints on the market and N.Glantz sell it. If she thinks they only make paint for aluminum, she needs a refresher course in what products they offer.

Just for information, most all Photopolymer processed ADA signs are painted with matthews paint. It's a 3 step process. There's an anti-static agent that gets sprayed on, then there's the "primer", and then there's the top coat.

Stuff dries extremely durable.

Matthews and Akzo Nobel are both used for that, and N.Glantz sells both, but doesn't mix any of them in Norfolk. They used to mix them there, but they have moved that all to another branch out of state (at least that's what they told me).

Larry Bratton
07-24-2008, 6:30 PM
Scott:
Ah..I see they have a branch in Columbia,SC. I will be contacting them. I need another good paint and supply source.

Aaron Koehl
07-25-2008, 8:49 AM
Scott, indeed, I found that to be the case when I googled it.

Well, off to Norfolk.

Aaron Koehl
07-25-2008, 10:42 PM
Here's the latest:

I went to N Glantz sign supply this morning, and fortunately they let me walk through the warehouse. I picked up some extra substrates to have around- some Corplast, a few vinyl banners of varying lengths, and some odds and ends, adhesives, etc.

I asked about acrylic drop offs (extra cut offs and/or damaged sheet), and they had quite a few pieces of acrylic in various thicknesses--you never know when you'll need some scrap--which I picked up for a few dollars on my order. They also had 'damaged' 4x8 sheets of various thicknesses as well, but I only had the SUV with me so couldn't pick up anything larger than about 4' square. I'm sure I would have walked with the entire lot for a steal.

The paint they recommended was Lacryl 200 series made by SprayLat (UK company). It ran about $16/qt, not exactly budget paint, and the smallest amount I could get was a gallon. I also picked up some of the corresponding SprayLat thinner- given the humidity I went for the slow drying. I expect I will be painting lots of things blue for a while. :D

I got home, suited up with the respirator, coveralls, gloves, etc., and went about making a test run on some old sheet. The paint dries very quickly which is nice (10 minutes, no longer tacky, 20 minutes, completely finished). I ran with the paint reduced about 50/50, but just eyeballed it for the test.

I had intended to use an HVLP sprayer but found I had not picked up one of the parts I needed for its use. That said, I ended up using a 1973 Sears Craftsman sprayer that's been on the shelf in the barn for a few years. It had just a little corrosion on the main pin, which I was able to scrape off with a blade. I applied a little Vaseline to the rest of the fittings and screws and the sprayer was good as new.

My results with the gun were much better than my attempts with a spray can, as can be expected. I coated an entire sheet of scrap 4x8 acrylic with about 4 tablespoons of paint. (Side note: I picked up a cheap plastic paint pourer at Lowe's that fits on a standard gallon paint can.. saved me from making a huge mess! I just need to come up with a way to pour the solvent out of that awkward rectangular container.. probably just need to get a funnel.)

My spray beam (vertical) seemed to build up slightly faster on the bottom than on the top. Hopefully, it's because the substrate I was painting was slightly angled, sitting against a prop. I suspect that if I prop it closer to 90 degrees that problem will go away.

I guess we'll find out tomorrow on the real sign.

Brian Stoddard
07-28-2008, 10:54 AM
Mathews or other urethane is the way to go if you cant use translucent vinyl but even at that it is very difficult to get an even spray pattern that will not look blotchy when backlit. They are also typically back sprayed on clear acrylic in reverse order - letters and graphics and then the background.