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If you want to produce a weathered effect on your model, generally the go-to type of paint to use is oil-based, such as enamels. But what if you don’t have any enamel paints, or just don’t want to use them for whatever reason? You can weather models with acrylics, but it’s not always as easy to produce good results. Here, I’ll walk you through weathering models with acrylics so that you can give it a shot.

An Introduction to Weathering

If you’re new to weathering overall, not just weathering models with acrylics, then read this section. If not, you can skip this and move on to the next section where I talk about specific processes for weathering models with acrylics.

The main idea behind weathering is to paint a model so that it looks like it’s been exposed to the elements and general wear and tear. When you weather a model, you have to keep in mind the setting. Is it rainy, muddy, snowy, dusty, or just old? For example, you may have a mud-covered battle tank; a dirty, graffiti-covered train car; or an old, sun-damaged sedan. The weathering techniques to create these effects and others will vary. I’ll be going over the most common of them and how to apply them with acrylic paint. However, I can’t tell you specifically what type of weathering to use—that’s something you have to decide. Here are some general guidelines to follow when thinking about what effect you want.

• Where there’s a lot of wear from foot traffic, on work surfaces (such as a portion of the bucket of a backhoe), etc. the paint will be worn down, revealing the material beneath
• Extended sun exposure lightens colors
• Paint wears a layer at a time. A logo may be chipped and faded, but the paint beneath may be fine
• If a decal is removed, the paint beneath will generally be clean and darker because the decal protected it from the sun and dirt
• Dirt accumulates in nooks and crannies
• Raised areas, such as the ridges along corrugated steel or the heads of rivets, generally have a bit more wear than lower areas
• Grease lines and joints on heavy machinery typically leak a bit of oil and grease
• There is often a directionality to wear, such as the constant scraping that occurs with heavy machinery

With these general rules of thumb in mind, we can move on to discussing weathering models with acrylics.

Weathering Models with Acrylics

There are a few common weathering techniques for models:

• Washes
• Filters
• Paint chipping

Wash

A wash is a method of adding color to creases and crevices in a model, usually used to show an accumulation of oxidation and dirt. It can also add a translucent patina to simulate dust over an entire area. Washes also help details pop out. You make a wash simply by adding a lot of thinner to paint. Because it’s so thin, it flows easily into crevices and around raised parts, the same areas grime would accumulate. However, it also flows everywhere else. Depending on your desired effect, you may have to wipe it off certain areas before it dries.

Despite what I said earlier about oil-based paints being the go-to paints for weathering models, acrylics make nice washes, and are often the best choice because the harsher thinners used to make enamel washes can damage the base layer of paint, whereas the water in acrylic washes is harmless. A key thing to keep in mind is that acrylics dry faster, giving you less time to work. If you have to do some cleanup as well, if you don’t clean the acrylic paint off while it’s wet, you’ll have to resort to a harsh chemical (the same is true for oil paints, but typically you’d be prepared for that if you were using oils).

To create and use a wash for weathering models with acrylics, follow these steps. Read them through and prepare everything first before beginning.

Thing you’ll need:

• Acrylic paint
• Dish soap or paint surfactant (optional)
• Fine-tipped paintbrush
• Flat paintbrush
• Soft paintbrush

1. Pour the acrylic paint from its main container into a separate container or onto a mixing palette. You often don’t need much because you’ll be thinning it a lot. Mix colors together as necessary to get the color you want.
2. This step is optional because it can have mixed results, and it may not even be necessary for the specific method of washing I describe here (there are times it’s helped me and times it hasn’t), so I recommend you experiment before trying it. Add a small amount of dish soap to the water you’ll be using to thin your paint. Use about a drop of dish soap per 1 ounce of water. This is done because dish soap is a surfactant, meaning it will decrease the water’s surface tension, which will help the wash flow into recesses and around raised details on the model more easily. Alternatively, you can add a special surfactant to the paint itself, such as Flow Improver (DO NOT add it to the bottle, only to the paint you’ve poured out).
3. Thin the paint with water (use your soapy water if you’ve taken that route) to the desired consistency. The opacity of the wash depends largely on what you’re trying to achieve, but the general rule of thumb is that the wash is more akin to colored thinner than thinned paint. Experiment as much as you can to get a feel for how to properly thin your paint.
4. Apply the wash by using the fine-tipped paintbrush to gently dab the wash onto the pertinent areas. This method is called a pin wash, and, while tedious, is the safest way to ensure that you get the effect you want and it’s easier to clean up afterwards. You’ll notice that capillary action will help the paint flow where you want it. Remember, acrylics dry fast, especially when thinned like this, so you may have to work a bit faster.
5. To clean up excess paint, use the flat paintbrush dipped in water and lightly dried to brush it away before it dries. Rinse the brush off in water and lightly dry it again as needed so that the accumulation of paint in the brush doesn’t lead to it painting the excess wash back on. You want the paintbrush to always be damp when you’re doing this.
6. Dirt buildup doesn’t often end in hard lines, so if you find that your wash is doing that (which can happen after cleanup), you can soften the edges. To do so, lightly dab at the hard edge with the end of a soft paintbrush, preferably one that isn’t high quality. A filbert brush would work best, but this can really be done with any paintbrush.

Filter

A filter is a weathering technique that slightly changes the color of a model. Whereas washes are applied to recesses and around raised areas of the model to simulate the accumulation of dirt, filters affect broader areas. They can simulate the fading of paint, an overall layer of dust, just slightly alter the color of the model, help blend colors together, and do many other things. They can be thought of as a tint added to the surface of your model. To apply a good filter, you’ll need an eye for color, which you can develop through practice and experimentation. I’m not going to pretend that my eye for color is any good, so what I typically do is paint several plastic spoons the same color as my model (or approximately the same, at least) and experiment until I find a mix that I like. Then I apply it to the model. If you’re new to this, keep in mind that colors you may not expect to use will likely find themselves in a good filter, such as pinks, blues, yellows, etc. When blended, these can lead to good earth tones. As you’re experimenting, don’t be afraid to try out some wild colors.

There are two main types of filters: the dot filter and the… filter. Yes, the second type is typically just called a filter, though I think of it to myself as a filter wash, because it is similar to a wash. But for the sake of consistency I’ll call it a filter here. Below I cover how to apply both using acrylic paint.

Dot Filter

Dot filters are really good for streaking effects, such as from rain, or rust running down from rivets or some such, though they don’t have to be used only for that. You’ll need the following to begin:

• Fine tipped paintbrush
• Flat paintbrush
• Acrylic paint
• Water or acrylic thinner

1. Use the fine tipped paintbrush to apply small dots of paint to your model in a small area in the pattern and colors that’ll create the effect you want. Don’t go over a large area to start because, especially with acrylics, some of the dots may dry before you can get to them. As I mentioned earlier, use a plastic spoon or something similar to practice and experiment with different colors. The dots will be semi-random, with some applied in specific areas to help produce specific effects.
2. Dip the flat paintbrush in water and lightly dry it (you want it damp, not wet) and use it to run over the dots in downward strokes. If the color is too heavy, keeping running over it with the paintbrush, adding more water or thinner as necessary. Using this method, you can also completely remove a dot if you want, as long as you get it before it dries. Your goal is typically to make the color barely noticeable. Of course, it’ll depend on the affect you want.
3. Lightly blend the dots and streaks of color as you go. You don’t always want streaks of individual colors running next to each other. The idea is to create earth tones without making one solid color.

That’s it for dot filtering. The process itself is very simple, but getting it to look good can be difficult.

Filter

The filter, or the filter wash as I call it, is similar to a wash in that paint is mixed with a lot of thinner, but a filter is a lot thinner than a wash because it’s supposed to be so faint. Recall, a filter is just a tint. A filter is usually thinned about twice as much as a wash, but experiment with yours until it’s the right consistency for your desired effect.

To begin, you’ll need:

• A wide, flat paintbrush
• Acrylic paint
• Water or acrylic thinner
• Something to mix the paint and thinner

1. Pour the desired acrylic paint colors into a separate container and add thinner. A good way to do this is to use eye droppers or a syringe for both the paint (if it’s thin enough) and the water. This allows you to be very accurate with your ratios if that’s what you want (though I don’t think such accuracy is necessary), or, more importantly, it prevents you from pouring too much in at a time.
2. Use your mixing tool (an old paintbrush, a paintbrush handle, even a toothpick) and thoroughly mix the paint and thinner until it’s homogeneous.
3. Dip the paintbrush into the filter and dry it slightly by painting the excess onto a piece of paper, then apply the filter remaining on the brush onto the model. Repeat until you’ve covered the model sufficiently. You can also apply this filter with an airbrush, but it’s harder to be accurate with an airbrush if you want to cover only a specific area. To use an airbrush, refer to the airbrush section of my article Painting Model Cars for Beginners.

Again, the filtering process is simple, but getting it to look right can be hard. Just practice and experiment.

Paint Chipping

There are several ways to simulate chipped paint. Which you use depends mostly on the effect you want to achieve and the size of the area. The chipping techniques that I’ll cover here are:

• Micro chipping
• Hairspray technique
• Masking fluid
• Salt chipping

Micro chipping

There are two basic types of micro chipping. This first type creates more of a 2-D effect and requires only one paint color. Choose a color that would look like whatever base you want to show through the top lay of paint, whether that’s primer or the material beneath (e.g. rusted or shiny metal). You’ll also need a fine tipped paintbrush.

1. Pour the paint into a separate container and thin as necessary. You won’t need much. For this technique, thinning is not often needed, but it may be for you depending on the effect you want and the type of acrylic paint you’re using.
2. Dip just the tip of the fine tipped paintbrush into the paint. Gently begin stippling the paint onto the areas of your model where you want the chipping to occur. Remember the guidelines from above for where wear occurs on surfaces. You can use a sponge instead of a paintbrush, but this doesn’t give you nearly as much control.
3. Move slowly, painting as small as you can and working your way up to larger spots. Have the patience and cognizance to know when to stop because it’s hard to go back once you’ve added too much.

The second micro chipping technique creates a 3-D effect, which looks more like a ding than a paint chip. For this you’ll need two paint colors. The first is a tint (i.e. a lighter version) of the model’s color. The second is the base material’s color, usually a rust or metallic color. Since this is a ding, whatever made the ding probably chipped through the primer, exposing the metal beneath.

1. Pour your colors into separate containers and thin as necessary. If you don’t have a tint of the model’s color, you may be able to create on through thinning. Don’t forget to experiment if necessary.
2. Grab the fine tipped paintbrush and dip just the tip of it into the tint of the model’s color and gently stipple it on where the chipping will be. When you’re done, clean your paintbrush.
3. After the stippling has dried, pour the base material color into a separate container. Dip your brush into it and carefully paint in the middle of each of the lighter colored stipples from before. Leave enough of the original stipple visible so that it forms a border around the base material color. The rule of thumb is to paint in the middle of the larger stipples, and leave the smaller ones alone. After all, you can’t paint smaller than the size of your brush, anyway.

Hairspray Technique

To use the hairspray technique for paint chipping, you need to use cheap hairspray. Make sure it’s unscented and not waterproof. Also keep in mind that this process only works with acrylic paint.

1. Paint your entire model in the color which you want to appear through the chipping, such as a primer or metal color, and let it dry.
2. Decant the hairspray into a separate container. A bendy straw attached to the hairspray nozzle with some putty can help. Make sure it’s attached securely or the straw may come flying off. Of course, you could spray directly from the can into the container without worrying about any straws.
3. Use an airbrush to spray 3 light coats of the hairspray onto the model on top of the base coat of paint you applied in step 1. Read the airbrush section in my article on painting for beginners if you don’t know how to paint with an airbrush. To clean the hairspray out of the airbrush when you’re done, follow the cleaning tips in that article using rubbing alcohol.
4. Let the hairspray dry for an hour or two before moving on.
5. Use an airbrush to apply the final color for your model and let the paint dry. Try to keep the coats thin because chipping off a thick layer of acrylic paint can be difficult.
6. Let the acrylic paint dry for about an hour. Don’t let the paint dry for too long because it’ll become difficult to remove during the chipping process.
7. To chip the paint, use a paintbrush to apply water to the areas where you want chipping to appear and let it sit for about 30 seconds. This allows the water to soak through the paint and into the hairspray beneath, which dissolves the hairspray and makes the paint covering it unstable, which makes it easier to scrape off in those specific areas. There are a variety of tools you can use to get the effects you want from this point on. If you want straight lines, you can use a toothpick, or a series of straight lines can be achieved with an old toothbrush rubbed in a single direction. You can even use masking tape to create stark lines. I usually just use an old, stiff paintbrush to scrub the paint off.

Masking Fluid

Masking fluid is usually liquid latex. You can use a sponge to easily apply it, which randomizes the spots, making the chipping effect look rather natural. For large chipping jobs, such as on large panels of vehicles, using masking fluid is by far my favorite technique. It’s easy and doesn’t require many precautions.

1. Paint your model in the color which you want to appear through the chipping, such as a primer or metal color and let it dry.
2. Apply the spots of masking fluid using the sponge and let it dry.
3. Apply the top coat of paint.
4. Rub away the masking fluid. You can use some putty or just your finger to do this. The paint covering it will be removed as well, revealing the color beneath.
5. If your base coat is enamel, you can use a small amount of enamel thinner over the chipped parts to make the paint run a bit, simulating rust bleeding through the paint.

Salt Chipping

Salt chipping is the poor man’s way to create chipping techniques. It’s not my favorite, but it’ll get the job done. All you need besides your paint are coarse table salt (such as sea salt) and tap water.

1. Paint your model in the color which you want to appear through the chipping, such as a primer or metal color and let it dry.
2. Pour the salt into a separate container and use a tool handle or similar to grind up the salt. This will break up the larger pieces of salt, creating varying sizes which will create a more authentic, randomized effect.
3. Use a paintbrush to spread some tap water on your model.
4. Sprinkle the salt on the wet areas and let it dry. The salt will adhere to the surface of your model. Shake off excess salt and use a stiff paintbrush or even an old toothbrush to clean up the salt from areas where you don’t want it.You don’t have fine control over the salt when you sprinkle it on, but by brushing it off in this way, you get better detail.
5. Use an airbrush to apply your desired number of layers of paint and let them dry. Keep in mind that the air from the airbrush may dislodge lose pieces of salt.
6. Use a stiff paintbrush to remove the salt once the airbrushed layer has dried. The salt can be a bit stubborn, especially when it’s covered with dry paint, so use a bit of water to help dissolve the salt so that it’s easier to remove. As you remove the salt, the paint covering the granules will come off as well, revealing the base coat beneath.

Conclusion

There are many weathering techniques out there, but these are good places to start. If you’re new to weathering models with acrylics, then these techniques will help get you started. If you’ve done weathering before but you want to know how to use acrylic paint to weather, then these techniques will give you enough to continue with using acrylic in what you already know how to do.