Airbrushing with Latex Paint

I use latex paint to make my roads. I thin 50-50 with windshield washer fluid (blue juice) and a #5 tip in my Model H. Its Behr brand from Home Depot but not sure brand matters much. Thanks to Norm C who came up with this method many moons and layouts ago.

Pete

Why don't you use Scalecoat Paints https://www.minutemanscalemode...m/category-s/127.htm 

They have all the railroad colors for plastic or metal. Don

It worked for this guy.  He used Windex too.

Have Fun!

Ron

Our shop has used the Paasche H airbrush for over 40 years. We primarily use the Benjamin-Moore latex house paint color system and have well over 400 colors in inventory. Several points based upon our experience:

1. Thin the latex paint (with water) and make sure it is well mixed. We use yogurt cups and strain the paint EVERY TIME it goes from the Snapple bottle to the yogurt cup. Thin it until the paint droplet on the end of your stirring stick just starts to run when tapped against the side of the cup.

2. Clean the airbrush regularly. Between coats you can just pull the cup or jar off and throttle the airbrush in a cup of water.  When done for the day, take it apart and clean it. Have a few pipe cleaners on hand to clean out the jar's tube or the cup's lead.

3. We find that tip 3 works best for basic painting. Use tip 5 to Earl Scheib a large flat surface at regular pressure or "spritz" droplets at lower pressure.

4. The cap has a plastic washer in it that is behind a small brass screw washer. It gets tired after a while and you will know it when the cap starts to feel loose on the pin or the paint refuses to come out. You can get a little more life out of it by tightening down the brass washer on the washer. If you use the airbrush a lot, buy some replacement washers because you will need them at some point. Having a few extras will save great anguish when the airbrush is acting up, and it will.

5. Practice on something that does not count first every time you go to paint something. 

Gonna take you forever to paint your house this way.

Thanks for all the tips! I'll be trying them in the very future. I'll keep you posted with my results.

Chris

LVHR

I had time last night to try this out. But as the pictures below show, I did not do something right.  

I'm painting a Lionel plastic bridge kit prior to assembly, so I left the pieces attached to the sprues.

I do have a Paasche H airbrush and have the #3 tip installed.

The inline regulator was set for ~30 psi, and the regulator on the compressor to ~60. There is no air tank.

I'm shooting flat black latex, which I thinned roughly 1:1 with water. The resulting mix is quite runny.

I adjusted the tip until I could see the spray coming out.

I laid down multiple coats (3-4 passes) until the surface appeared wet, then leaned the sprues against a wall to dry.

The pictures show what I found this morning. The wet paint appears to have bunched up, rather than "wetting" the surfaces. Other than laying the sprues on a flat surface, what do I do to keep the paint even? I don't remember having this issue when I shot solvent based paint on plastic surfaces.

Chris

LVHR

Why? When there are so many alternatives in rattle cans and oil based paints. Latex is not meant for plastic- it won't bite or stick. And latex is certainly not for use in air brushes.

For an item of that kind, you might have gotten away with flat black latex paint on a brush. Also might have been able to spray with gray primer and then apply latex by brush.

MELGAR

@lehighline posted:

I had time last night to try this out. But as the pictures below show, I did not do something right.  

I'm painting a Lionel plastic bridge kit prior to assembly, so I left the pieces attached to the sprues.

I do have a Paasche H airbrush and have the #3 tip installed.

The inline regulator was set for ~30 psi, and the regulator on the compressor to ~60. There is no air tank.

I'm shooting flat black latex, which I thinned roughly 1:1 with water. The resulting mix is quite runny.

I adjusted the tip until I could see the spray coming out.

I laid down multiple coats (3-4 passes) until the surface appeared wet, then leaned the sprues against a wall to dry.

The pictures show what I found this morning. The wet paint appears to have bunched up, rather than "wetting" the surfaces. Other than laying the sprues on a flat surface, what do I do to keep the paint even? I don't remember having this issue when I shot solvent based paint on plastic surfaces.

Chris

LVHR

Did you first wash the plastic thoroughly in warm soapy dishwater, then rinse and dry?  The plastic may have had mold-release agent on it (allows easier release from the steel molds).  Which can cause paint to do all sorts of strange, ugly things.

For that matter, as others have mentioned, latex (and some other water-based paints) do not adhere well to bare plastic.  I almost always prime any plastic with red oxide or gray spray-can primer before using water based paints.  That generally does the trick for getting a good paint job.

Also, I would recommend gluing all of the bridge kit (or as much as possible) together before painting.  Your glue joints will be much stronger that way.  Otherwise, any joints afterwards should be scraped down to the bare plastic before gluing.

I agree with Paul. Something on the plastic caused too much surface tension. Latex is OK on plaster or wood or wood products like MDF but not for plastic or metal. Rattle can would have been much easier and not do that.

BTW some of us suggested thinning with windshield washer fluid or even Windex. One of the reasons is to reduce the effect of surface tension. Same reason you should thin white glue with alcohol and/or dish soap so it flows better when glueing down scenery.

Pete

It amazes me how you guys keep trying to reinvent the wheel!

@Big Jim posted:

It amazes me how you guys keep trying to reinvent the wheel!

Well, Earl Scheib Deluxe - why don't you lay your painting expertise out and let everyone know what the solution is, instead of making inane comments while letting everybody flounder helplessly about.

Or maybe you don't have anything tangible to add?

A couple more latex paint airbrushing thoughts:

Yes, all items should be primed. We use Krylon Gray Primer as our go-to primer. Sometime we’ll us the Oxide Red if we’re painting a brick color. I always suggest that “less is better”, so two or three light coats can be better than one. Always try to paint the hard to reach corners first, whether is primer or final color. That way by, by the time you get paint to inside corners most of the remaining surfaces have paint on them. If money is no object, automobile lacquer based primer is the best and is also very good for small or extremely detailed parts.

Start with the rattle can off of your work area and move uniformly over the area to be painted. Try to refrain from the aim and swirl approach to getting the paint on a particular spot. It almost always causes a hot spot- too much paint resulting in a run or paint filling in detail.

If you get what we call alligatoring, most likely there is either too little or no primer. Either wash it off if it is still wet or let it dry and sand.

If you get what we call paint dots or fisheyes with rattle cans, stop right away and let it dry. Although I don’t know why this happens, it can occur if the surrounding temperature is too low, there is oily residue in the surface that you are painting (can be caused by just your handling), or a bad can of paint. We have to watch out when we use Krylon Gloss White and other light gloss colors.

I broke out the Thayer and Chandler Omni T-83 (now Badger 155-7) Double-Action airbrush, and my  compressor to make some trees out of "seedoms".  I used cheap. craft store acrylic paints, thinned w/ water.

A good basic how to model railroad article: (I wrote it many years ago!)

http://www.amherstrail.org/ABE...oads/Airbrushing.pdf

Craft store acrylics are as different from latex paint as automotive lacquer is from varnish. They all use different thinners. Just because they are all water based or solvent based doesn't mean you treat them the same way. Look at Floquil, Scale Coat, and Tru Color. All thinned with different compounds.

Pete

There was an article about spraying craft store paints in the June 2015 Railroad Model Crafstman written by Gregory M. LaRocca.  The advantange of Craft Store paints are they are cheap (less than $2.00 per bottle), available in an extremely wide range of colors, and can readily be mixed.   To spray them he mixes them with Liquitex Airbrush Medium to get the conistency of skim milk, and a few drops of Liquitex Flow Aid.  The latter is an emulsifier that lowers the surface tension of the paint. I have been using Dawn in all my acrylic airbrush mixes for the same purpose.

I HATE AIR BRUSHING AND AIR BRUSHES.  I know I am very much in the minority on this.

I have purchased the very best (and expensive) airbrushes and still had issues. Latex paint is the worst. But even oil-based paints clog my brushes.

So i now buy the cheapest airbrushes I can find; and throw them away after the first use.  They work fine one-time!

@Ron045 posted:

If people didn't reinvent the wheel, we'd still be driving cars like this.

The wheel there wasn't reinvented, it was the automobile!

I keep a few cans of Home Depot flat black spray paint on hand all the time for projects just like this. Mist the first coat or two on then give it a final blast so as not to put it on too thick.

@Big Jim posted:

The wheel there wasn't reinvented, it was the automobile!

As suspected earlier, nothing tangible here.

@John Sethian posted:

There was an article about spraying craft store paints in the June 2015 Railroad Model Crafstman written by Gregory M. LaRocca.  The advantange of Craft Store paints are they are cheap (less than $2.00 per bottle), available in an extremely wide range of colors, and can readily be mixed.   To spray them he mixes them with Liquitex Airbrush Medium to get the conistency of skim milk, and a few drops of Liquitex Flow Aid.  The latter is an emulsifier that lowers the surface tension of the paint. I have been using Dawn in all my acrylic airbrush mixes for the same purpose.

I have wondered the past few years about using "wet" water as a thinner myself.  I am assuming you've had good luck doing that.  I will give it a try the next time I do some airbrushing.

Thanks for confirming my suspicions! 

@AlanRail posted:

I HATE AIR BRUSHING AND AIR BRUSHES.  I know I am very much in the minority on this.

I have purchased the very best (and expensive) airbrushes and still had issues. Latex paint is the worst. But even oil-based paints clog my brushes.

So i now buy the cheapest airbrushes I can find; and throw them away after the first use.  They work fine one-time!

Alan, I can understand your frustrations about airbrushing.  Actually, I have pretty good luck with airbrushing, but I will admit that it takes a fair amount of work to get everything ready to go, a fair amount of knowledge to do everything properly, and a fair amount more work to clean everything up when you're done.  More hassle than it's worth for the normally small projects that I do, as far as I'm concerned.

As a result I don't airbrush very often.  Fortunately, spray can painting suits my needs 99.8% of the time.  I use rattle-can spray paints as often as possible! 

Oh I agree with the rattle-can use; but sometime the color is just not right.

@AlanRail posted:

I HATE AIR BRUSHING AND AIR BRUSHES.  I know I am very much in the minority on this.

I have purchased the very best (and expensive) airbrushes and still had issues. Latex paint is the worst. But even oil-based paints clog my brushes.

So i now buy the cheapest airbrushes I can find; and throw them away after the first use.  They work fine one-time!

I find it more difficult too. I always end up spending more time thinning the paint and cleaning the tip than actually painting. It's so much trial and error. Also, you need to have the right compressor. One of my problems is that I am using a commercial compressor instead of a hobby one.

As for Behr paints, I tried that. It was a disaster. Maybe I should have thinned it with water. It was SO thick though. I would use a custom automotive mix first.

As for painting plastic. I never do it without priming or a primer + paint rattle can.

George

Having recently resumed painting aluminum passenger cars, I've found two things have made it much easier than I remember it being when I last undertook such projects 25 years ago.

First, the Badger 350 single action airbrush is easy to clean by removing a single threaded assembly; and, second, I've begun using a paint cup instead of the siphon cups with tubes.

Some Q-tips, gauze pads, and pipe cleaners along with the appropriate cleaning fluids makes for a pleasant experience from start to finish.

I use my Paasche airbrush all the time. Very easy to use, take apart to clean, and gives outstanding results, every time. I use Floquil and Scalecoat II paints vented thru my paint booth.  I’ve never tried latex paint and likely never will. With the amount of hobby paints available I see no reason to use that type. 

@Jeff78rr posted:

I use my Paasche airbrush all the time. Very easy to use, take apart to clean, and gives outstanding results, every time. I use Floquil and Scalecoat II paints vented thru my paint booth.  I’ve never tried latex paint and likely never will. With the amount of hobby paints available I see no reason to use that type. 

Exactly!
I have no idea what some of you are doing that makes it so hard for you to use an airbrush, but, there is really nothing to it. If you are using rattle cans for small parts, you are only wasting paint. The control of the amount of paint and where it goes using an airbrush alone makes it worth its weight in gold!

At this point I think the latex/plastic substrate is just a bad combination. Those of you who suggested cutting the surface tension are probably right. But at this point, enough. The experiment is over. I thought I would try this route b/c a) I had latex paint on hand, but no acrylic, and b) I like the control an air brush offers as compared to a rattle can. 

It's interesting: Lionel's instructions for this bridge say if you are going to paint the bridge, do that first, then cut the parts from the sprues. So that is what I did. I retrospec, if I had acrylic in the air brush, painting it second would be fine, as I would have the necessary control. Rattle cans just don't have that kind of control for getting into nooks and crannies w/o dripping elsewhere.

Chris

LVHR

Totally agree on a couple points Chris. Airbrushes are superior to rattle cans when trying the get into nooks and crannies. I will spray a rattle can into an airbrush bottle for projects like painting steam engines with lots of piping and add on details. 

On your other point you picked the wrong combination to try using latex on.

It has its place, just not on detailed models. 

Pete

 I generally paint and weather steamers with Scalecoat 1. Just getting the cap off the bottle is sometimes a chore if it’s old. I needed some clear flat to seal in some decals. What was left in the bottle was like molasses. I had a rattle can of Scalecoat flat. I did what Pete suggested and spayed it into a bottle. Added a little more thinner and it spayed really well. If it can come out the rattle can nozzle it will certainly come out the airbrush. I may go this route and just buy the few colors I use rather than deal with the bottles. I still would have the option on some jobs of just spraying from the can.

Here is the final result. I used rattle can flat black, then shot the railings by airbrushing with latex flat grey primer and then latex yellow. I used the latex in both instances b/c I had it readily available. I figured with the flat black already there, the latex would behave, and it did. Given the major PITA the masking job turned out to be, I should have left the railings attached to the sprues by the legs and cut everything else off. Also, it is hard to get good coverage with yellow. This took about 6-7 coats to get it where it is now.

Chris

Chris, 

You do remember you final ratio of paint to Windex?  Did you use anything else like flow improver?

Ron

Ron,

I used straight water, no windex. For the gray, I cut it 1:1 by volume. That worked well. For the yellow, 1:1 was too runny. I was probably closer to 2:1 paint/water by the time I got done. Even then, I was thinking about bumping the paint up, because it was not covering well. I did not want to go too far, because at some point, things will get too think and won't flow well. I did not hit that point.

Chris

LVHR