# Quick easy weathering with abrasive blasting and acrylic wash



## zr1rob (May 27, 2020)

A fellow visited my layout last week and watched a train running. He's not a modeler, but likes trains in general and has been very much interested as he watched me build the layout over the summer. But what stood out to him was when a heavily weathered tank car rolled by and caught his eye. It stood out to him so much so that he said it looked 'real'. He gave lots of compliments but no other specific comments other than that regarding the tank car. I didn't weather the tank car, I bought it several years ago already weathered this way:










Why did the worn out looking car mean something to him? Because he wants to believe this fantasy world is real. And when he saw something 'real', it cemented his escape into the fantasy world of the model train. 

His impression gave me an idea. Find a way to weather rolling stock that is easy and really fast, is cheap, and gives 'real' good results. I found one way with abrasive blasting and acrylic paints. Here are the tools I used:










An airbrush, a hobby Air Eraser, some baking soda, distilled water, and acrylic paint. The color I chose was dark brown because the car I'm using for this example is a Santa Fe stock car that probably would be used in the southwest US, where the air will deposit a fine layer of dust on anything in a matter of hours. (I can prove it - I wash my black truck and come back after lunch and you can print "WASH ME" anywhere with your finger). The Air Eraser is nothing but a subminiature sandblaster. I fill it with used up baking soda that is no longer fresh enough to absorb odors from the fridge. I used to throw it away, or send it down the kitchen drain. You can also buy abrasives specifically made for the Air Eraser, but just run the air at 60-80 psi with baking soda and you'll get the same results.

I have cars that have really bright lettering, like this one:


















I want to not only dull the lettering, but make it seem more a 'part' of the car's paint. This car's lettering sticks out pretty far from the car, making it look too toylike to me. So by blasting it with the Air Eraser and baking soda the lettering gets flattened and pitted so when washed later with the acrylic paint 'dirt', the lettering looks like its on the same level with the car's paint. Here's the Eraser hitting the lettering:










And here's the car (also the ends) after blasting with baking soda:









The cars basic color doesn't have to blasted unless it really needs to look distressed, the wash will do a good job of that. The goal should be to make the lettering look 'weak'. That way, the acrylic wash's only job will be to add the dirty look, not obscure the lettering too. 

BTW: if the Eraser nozzle gets clogged, which it will from time to time, simply take a brush or toothbrush and stick a bristle in there, sometimes that works. Otherwise, just unscrew the nozzle and with your air gun blow from the nozzle end to dislodge the obstruction.










After blasting the lettering, air gun the entire car to get the baking soda off.

Pour some of the acrylic paint into a small plastic cup, then add an equal amount of distilled water:


















Use distilled water to avoid the minerals present in most other water, including tap. Now be Mr. Non-James Bond and stir, don't shake to mix it up. Stir it real good so there are no lumps to clog the airbrush. Test spray on something that won't absorb the water, like a piece of plastic. If the test spray lays out as mostly paint, then there's too much paint. However, there has to be enough paint so when the water dries, there's some of the acrylic paint 'dirt' left on the car.

Now spray the entire car with it sitting on its wheels. On the roof, spray above it and downward at 45deg so the wash runs down toward the car sides, just like if rain washed the dirt that was sitting on the roof downwards. For the sides, spray downwards close to 90deg to simulate dirt going downwards from the top of the car. The acrylic 'dirt' will find the natural places actual dirt will find, and dry there. Don't forget the ends of the car.

Next, wait a while for this to dry. I did this outside on a warm day, so it only took a few minutes but these first steps have to dry before the next step because the car goes onto its side for the final step and we don't want the acrylic 'dirt' to dry in a gravity-defying location!

The last step is to lay the car on its side. Spray from the bottom, pointing up nearly parallel to the side of the car and from below the trucks, up the side of the car about 1/4 of the way up the side, stopping just toward the middle of the car. You want to simulate the 'dirt' that gets kicked up from the trucks. Dirt will also be heavier at the bottom of the car side between the trucks, but not as much so go up about 1/8th the way, fading away as the airbrush goes upwards. The ends get their fair share of extra dirt kicked up because its a low pressure area and the dirt settles there, but mostly that seems to occur on open end cars like hoppers. 

From start to finish the whole car took me about 25 minutes. The cost of the baking soda is really nothing since it was going down the drain anyway, and the acrylic paint is less than $3 and will do several cars. The distilled water is always useful for many things around the home and is less than $2/gal. The expensive stuff are the air tools and compressor. I had the air brush and the compressor already from other projects, so the air eraser had to be bought. I'm happy with the eraser as it has many hobby uses.

Here is the finished car:









My goal accomplished, I look forward to doing more cars in the future.


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## Pete Thornton (Jan 2, 2008)

Looks really good. 

I usually 'wash' with a 50-50 mix of paint and water (like you) but I splash it on the upper part with an old brush and let it run off. I suspect I use about twice as much as if I used an airbrush, but it sure runs down prototypically. I do tend to blot the bottom of the side if it is making a big bead.


Occasionally I do the bottom of the sides, like you, but with a rattle-can spray, but it is tough to keep the amount under control.


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## Homo Habilis (Jul 29, 2011)

Nice job on the cattle car. Thanks for the write up and pictures.

There was an excellent 3 part series by Kevin Strong in Garden Railways 2018, volume 35, issues 4, 5 & 6 on weathering basics. Many good tips and techniques.


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