experiments in spraying acrylic

[bjphoenix]

Due to the problems I've been having with Rustoleum rattlecans I decided I should try spraying acrylic so today I started some experiments in spraying hobby acrylic paints. The first photo shows the old spray gun I was using, something given to me many years ago. It has a nozzle that measures about 1.2mm. I bought a cheap bottle of paint at Hobby Lobby and thinned it 1:1 with plain water. I did some experimenting with spraying on pieces of cardboard but it doesn't show very well what is happening. I tried spraying some soft drink cans and some glass jars.

The slick surfaces of the bottles and cans didn't seem to take the paint very well, it appeared that surface tension made the paint gather up into discrete droplets. You can see some of this on the can in the third photo. Maybe a proper thinner would help, and/or using some kind of wetting material such as is used in dishwashing detergent.

The first coat on any material was discouraging but I decided to keep trying. I let the first coat dry and sprayed a second coat, third coat, etc. I noticed on the glass jar that the paint evened out better on the paper label so I thought I should spray something more representative than a painted can or glass jar. I found an old Gatorade bottle and put a quick coat of gray primer on it. After that dried I put 4 coats of the acrylic on it. This gave a pretty even finish. The color is pretty dull though, not a very bright red. In person it looks maybe less bright than in the iphone photographs, the glossy clear helps a little bit. I then sprayed some rattlecan clear on half of the bottle, visible in the second photo, to see what the color would look like if glossy. Another thing- the acrylic doesn't seem to bond very well to primer. Maybe other acrylics are better than this, and maybe a harder clear coat might help that too.

Overall it appears that this is a reasonable method for painting rockets, certainly larger rockets. I'll have to research the thinner issue a little more, and try to find a source for larger, cheaper paints in more variety of colors, and it might be time to invest in a good detail spray gun from Amazon.

 

[Banzai88]

Here's a source, and several brands of paint that are orders of magnitude better and easier to use for what you're wanting to do.....although it comes at an increased cost.

https://tcpglobal.com/pages/airbrush-paint-home
Of course, the ultimate trouble with water based hobby acrylics is that they require a relatively thick coat to get coverage, dry sorta rubbery soft, and need to be clear coated to be durable, preferably with something oil based.

 

[Bill S]

You may want to use a primer on whatever you are painting first.

As a side note, I paint metal gaming miniatures, and despite them being primed, I occasionally find one that the first coat of acrylic paint (brush painting, not spray) can be somewhat blotchy. But if I let it dry for a while and then continue to paint it, everything works fine. Not sure why that is.

 

[mh9162013]

I just purchased an airbrush and from my research online, people use the cheap bottles of acrylics (like you used) in their airbrushes without issue. I saw one video where the thinner used for it was distilled water. Not sure if regular tap water would work any worse, but that's something to consider. Another thinning option is rubbing alcohol.

Lastly, airbrushing acrylics on super-smooth surfaces like glass, aluminum cans and plastic bottles is challenging, even for the higher-quality acrylics people use for plastic models. That's why primers are so common in these applications.

When you were done diluting your acrylics for this test, was it the consistency of milk? That's a common goal to shoot for, although you'll need to tweak it based on your preferences, airbrush and compressor pressure.

 

[neil_w]

I've experimented with brush-painting the Craft-smart acrylic and it works OK, although it is extremely matte and I needed to sand and clear-coat (Future) to bring it up to a good-looking surface finish. I agree that it will benefit greatly from a primer coat, especially on difficult surface types like the OP tried. I got decent adhesion brushing it directly on lightly-sanded paper tubes.

 

[DigBaddy]

Thinner recipe for cheap hobby acrylics that I use. I then thin to about 40% paint to 60% thinner; but varies.

• 2/3 Distilled Water
• 1/3 99% Isopropyl Alcohol
• 1 drop Glycerine for every 50 ml of the mixture

Primer is a good idea....

This is cheap acrylics through airbrush with that thinner. Done many more as well. Perhaps I could go into an illustrated guide sometime....
https://www.rocketryforum.com/threa...sport-k-42-or-1242-gallery.15852/post-2367583

 

[bjphoenix]

When you were done diluting your acrylics for this test, was it the consistency of milk? That's a common goal to shoot for, although you'll need to tweak it based on your preferences, airbrush and compressor pressure.

Yes it seemed about like that.

 

[bibbster]

A cheap Harbor Freight trim gun is what I recommend. Get the 20oz version for larger projects.

https://www.harborfreight.com/air-t...y-guns/adjustable-detail-spray-gun-92126.html
https://www.harborfreight.com/air-t...oz-hvlp-gravity-feed-air-spray-gun-62300.html
I use the cheap craft paints from Wally world and hobby lobby. Thinned with water to the consistency of blood. Morbid but you get the idea. Lol You want the mixture to cling to the walls of your mixing cup and not run off like it's coated with rainx.

 

[John Kemker]

If you're going to HL, the one near me, at least, carries Createx acrylics. Good coverage, easy to thin, excellent support form their website. The same paints are sold for painting cars and motorcycles, as well.

 

[bjphoenix]

Well another one bites the dust. I'm finishing up a few models in progress and one of them needed a few red stripes and a couple of red fins. I have a can of Rustoleum red that is less than a year old, about half full, so I started spraying it today. Spraying the stripes went well as well as the first side of the first fin. I flipped it over and the can suddenly started barely spitting. I kept at it with the spitting and managed to get the sputters and spits to cover the entire fin, and the second fin. So I guess now that's another half a can down the drain. Today's temperatures in the mid 80s.

 

[DrJoe]

If you spray acrylic over papered fins, you may get a lot of wrinkles in the paper... I did but stopped as soon as I saw the wrinkles form and it did dry out flat. Might want to prime with non-water based paint first.