Using an airbrush?

[mikesmowers]

  I have been trying out my new airbrush and have a couple of questions.

    1.  It seems I have to thin the paint (Acrlic from Wal-Mart) quite a bit to get it to go thru the airbrush. Almost like water, Is this normal? Do I need to use a different needle and tip assy. to get the paint to spray thicker or is this normal for an airbrush? I am running about 25 psi. maybe more psi?  I have 3 different sizes of needles, I assume the smaller needle/tip assy. is for thinner materials, India Ink and water, and the bigger needle/tip assy. is for the thicker paints. Is this correct?

    2.  How long can I safely leave the paint in the airbrush without it drying?  I can see that I will have to apply several very light coats and let it dry before applying another coat in order to get a good coverage. Do I need to clean the airbrush everytime I put a coat of paint on the model? This could get very time consuming.

    I am trying to use my new Paashe internal mix, I have never used an internax mix airbrush before. I want to do a lot of practicing with it before I start painting the passenger cars I have, The UP Armor yellow should be here towards the end of the week.

  Thanks for the help, I know you folks here will help me with this as you have always helped in the past.                Mike 

[loathar]

It's normal to have to thin craft paint a lot. Someone said Ceramacoat makes a thinner specifically for craft paint that works the best.

Tip size determines spray pattern. Smaller tip, smaller pattern. You probably want to use your medium or large tip for craft paint. (something about larger pigments)

Paint dries REAL fast in an airbrush. I always clean in between coats.

[spidge]

I am no expert and have only used my airbrush three or four times so my info may not be right on.

The needle size is as Loather said, patern size.

I don't think Loather meant for a complette tear down and cleaning of the airbrush between coats, rather to rinse it thoroughly. I run water based paints and run water until its clear.

I must say the results with my airbrush have been very pleasing. I found that weathering and general wear and tear painting needs to be a bit darker than it looks while painting. I like to shoot everything with a final coat of dust to tie it all together and this lightens everything a bit.

P.S. watch out for overspray. It will do more than you think. I taped off a line once and the overspray ended up on the other end of the model.

[jeffrey-wimberly]

I have a dual-action airbrush (I'm thinking testor's, but there's no brand name) that I quit using partially due to my disabilities but mostly due to the massive thinning required and the cleanup afterward. Disassembling the airbrush and separating out all the fine parts was just too much for me. I changed over to a single action external mix airbrush that doesn't require a lot of thinning and only three parts require cleaning, the bottle, the nozzle and the vacuum tube. Hey, it works for me.

[sfrailfan]

I just wanted to chime in and stress cleaning the airbrush when you finish is very important. If you don't the paint will dry inside. To clean just run a bottle of straight water and then clean or change color.

(acryllic drys to the touch in a few minutes and completely in 10-15, less when thined)

If that happens, you will have to completely dissasemble and clean with some alcohol or other heavy duty cleaner.

I always dissasemle and clean after every session.

[modelmaker51]

You don't need to to completely break down an airbrush between coats. With a dual action/internal mix, just pull the paint container off and pull the long pin/needle and run water through it, occaisionally holding your finger in front of the brush to back flush, shouldn't take more than 30 seconds. With a single action, remove the paint container and open the cone all the way and do the same as above. If you don't have a faucet and sink nearby, keep a tub of water next to you painting area and just submerge the airbrush as you push air through it.

PolyScale and Modelflex paints need to thinned to the consistency of milk and one should use the medium/#3 tip assembly. #1 is indeed for inks and very thin solvent paints. You can push acrylics through if thinned enough, good for detail/weathering work, but not recommend for general coverage. #5/Large tips are for thicker stuff and/or large coverage, like scenery painting.

To make your painting with acryl;ics more trouble free, I recommend straining your paint first. I "borrow" some of those little plastic condiment cups from MickeyDs and cut up 2" squares of stockings. Most Hobby shops carry the little 1 ounce cups for mixing epoxies, if you have a SoftCo store in your area you can these in large quantities for real cheap.

I hold the screen over the cup and pour the paint from the bottle, (about 1/4 to 1/2 fullof the cup for the 1/2 oz cup, half that for a 1 oz cup untill you get the feel of how much you need for the session), thin it and then pour into the air brush container and spray. I use the paint cup - less to clean up when done.

Do NOT paint directly from the original bottle, there's usually some gunk in the bottom of the bottle and that'll get sucked up clog the works in no time.

Now, I know a lot of people say don't pour the thinned paint back into the bottle, (true for solvent paints), but with acrylics I haven't had any problems doing this over the past tweny years of custom painting, I do strain it again when returning paint to the original bottle.

Well, that's my 3 or 4 cents worth for today. Have Fun and practice, practice, practice!

[loathar]

Buy yourself some extra bottles. I keep 2 with thinner in them for in between coat cleaning. Save your old Floquil and Polly Scale bottles for storing your thinned paint. I use soft pipe cleaners for cleaning my brush and bottle tubes. Just make sure you don't leave any lint behind.

Are you using an air compressor or can-O-air? Automotive paint stores sell cheap in-line air filters pretty cheap. The kind that mount on the handle of an auto spray gun work great when mounted on the compressor.
http://www.autobodytoolmart.com/pc-10744-562-2889-astro-disposable-in-line-filter-6803.aspx

 

[jeffrey-wimberly]

Yes, a moisture trap is an excellent idea. I have one on my compressor to catch water and keep it out of the airbrush.