One of the easiest ways to add a level of fine detail to your structures is to add mortar between the bricks of your structures. Many modelers shy away from this detail and find it intimidating.

There are a number of ways to add mortar, which I’ll explore briefly here, but I’ll focus on the one method that I’ve had the most success with.

I find that adding mortar is most successful on larger brick — brick that is over-scale like the brick that you’d find in many commercial N scale kits.  Kits from Walthers, Vollmer and Faller seem to work well since the brick detail seems to be closer to HO scale.  If you’re scratch building using truer N scale brick size like the brick sheet from N Scale Architect or building a DPM (Woodland Scenics) kit, it may be a little more difficult to work with the mortar lines.

Charcoal Wash

The charcoal wash is the method that I personally use. I’ve tried other methods, but prefer this one because I think it’s fairly easy to get consistent results without a lot of work.  The best part of this technique is that it’s very forgiving and can be reworked if necessary.

You’ll want to be thinking ahead when you plan to add mortar with charcoal.  Since you’ll be using Dullcote to seal the model surface, the Dullcote should be applied before you add window glazing. Dullcote spray will remove the reflectivity of the glazing, which does not look correct in scale. The glazing would end up looking dirty or foggy once strayed.

I typically do all of these steps BEFORE window glazing is added.  However, if you have a previously built model, this can work for you if you’re careful and your model has already been sealed during the construction process.

What You’ll Need

• Testors Dullcote (or similar clear-coat finish)
• White compressed charcoal sticks (I’ve only used white charcoal for this, but other colors are available)
• Large jar
• Water
• Dish-washing detergent
• Large, soft brush
• Kneaded eraser (optional)

Sealing the Model Surface

When adding mortar to your structure, you’ll first want to seal the walls of the model with a clear-coat finish. Something like Testors Dullcote works well.  This assumes that you’re starting with model walls that are already painted the color you’d like the brick to be.

This step is necessary because we’ll be adding water to the surface of the model in a later step, so you’ll want to be sure the walls and any paint you’ve previously applied are sealed against the water – especially if you’ve used acrylic, water-based paint. Also, the Dullcote will provide a slightly rougher service for the applied charcoal to adhere.

Follow the drying time on the Dullcote can’s instructions and be sure the coat is absolutely dry before moving on.

Creating the Wash

To create the charcoal wash, first, use the edge of an Xacto blade on the compressed charcoal sticks to shave off charcoal dust from the into a large jar.  I use a jar that holds about a pint of liquid, but that’s not critical. I usually cover the bottom of the jar with a layer of charcoal dust.

Then, you’ll want to fill the jar approximately half to 3/4 full with water.  It’s important to fill it only a portion of the way because that will give you room to adjust the wash by adding more water to lighten the effect if necessary. Also add a drop or two of dish-washing detergent which will help break the surface tension of the water and allow it to flow smoothly.

With the charcoal, water and detergent added to the jar, you’ve essentially created this very simple wash.  It is a white wash, but the white will not overpower your model and will not appear stark white.

You’ll notice that the charcoal particles don’t directly mix with the water. They’ll make the water cloudy, but after a while all charcoal will usually sink to the bottom of the jar. This is correct — don’t worry, the real trick with this is in the application of the wash which we’ll get to next.

Applying the Wash

You’ll apply the wash one wall at a time by laying your model on its side, working with each wall while it’s horizontal.

Using a large, soft brush, stir the charcoal and water mixture so that the particles of charcoal are suspended in the water.  The water will become slightly cloudy.  As the water starts to settle again, dip your brush deep into the mixture and be sure you’re getting particles on your brush.  Stirring the mixture first helps the particles adhere to the brush so that you’re not scraping them up off of the bottom of the jar.

Then simply brush the wash over the brick surface.  At first, this will most likely not look like mortar at all and you’ll probably see individual particles on the brick surface.  But as the water evaporates and the model dries, the wash will be left in the mortar lines. This method also tends to leave a light white haze on the brick surface making them look a bit aged. It will take a few applications and allowing the surface to fully dry before you will be able to tell how much wash to put on.  After you get the hang of it, it becomes very easy to know the right application.

The charcoal is much more forgiving than a paint wash because the charcoal can easily be washed or lightly scrubbed off of the surface.  Because of this, it’s very easy to apply more wash to make it darker (add more charcoal dust) or use a plain water to lighten it or move it around.

After the surface is dry, I often us stiffer brush with clean water to lightly clean the brick faces if I feel like too much wash was left on the surface. In some cases, I’ve applied several layers of wash followed by several cleanings to get just the effect I was after. Optionally, you can use an artist’s kneaded eraser to remove dried wash from the brick surface without introducing more water if you find the clean water approach is too difficult to do without disturbing the mortar lines.

Just keep in mind that because the charcoal doesn’t “dry” like paint would, so applying more wash (water) will undo most of what you’ve previously done. Again, you’ll get the hang of working with this technique.  It’s a little bit different than what most modelers are used to. If you do want to “build up” the effect and layer you work, you would just need to apply a coat of Dullcote between wash applications.

Once the surface and mortar has been completed to your liking be sure to use another coat of Dullcote (making sure the surface is completely dry first) to permanently seal your work.

The Results

The results of the charcoal wash are relatively subtle.  These photos make the mortar look very white with quite a bit of contrast.  In reality, it’s relatively subtle and only stands out when the light strikes it right right.

Other Methods

Paint Wash

A paint wash is similar to the charcoal wash outlined above, but instead of charcoal, a water-based acrylic paint is mixed with water.  Typically, a mix of about one part paint to 16 parts water will create a decent wash. Adding a very small amount (a drop or two) of dish-washing detergent will help break the surface tension of the water and allow it to flow into the cracks better.

The wash is brushed onto the surface (with the model on its side) and allowed to run into the mortar lines.  The wash will evaporate off of the brick surface leaving paint in the lines.

Once allowed to completely dry, this approach will let you to layer the washes, making them darker as you go.  It also tends to leave a slight haze on the surface of the bricks.

Personally, I don’t like this approach as much as the charcoal because the paint is more permanent — and I like to have a margin for error. Like with the charcoal method, I’ve read that the brick surface can be cleaned with a kneaded eraser if necessary.

Paint washes are probably the most common method for adding mortar detail.

Dry Brushing

Dry brushing is a technique where most the paint is removed from your brush by wiping it on a paper towel.  The brush still has trace amounts of paint, but is mostly “dry”.

In this method of mortaring, the entire structure wall is painted the color of the mortar.  Then appropriate colors for brick are dry brushed with very light pressure over the surface of the bricks.  Because there’s not enough paint on the brush to run into the mortar lines, only the bricks themselves receive paint.  This method also allows the modeler to vary the color of brick in different areas by changing the paint color slightly while dry brushing.

I personally have had difficulty with this method.  I find it quite time consuming to dry brush an entire structure, and because the dry brushing is not “solid”, I think too much of the mortar color shows through in the end unless you really spend a lot of time with it.  However, some modelers swear by this approach.

Colored Pencils

As with dry brushing, the model surface is entirely painted the color of the mortar.  Colored pencils are used instead of dry brushed paint to color the individual brick surfaces.

Some modelers like this method as it gives quite a bit of control to the color of each brick and is especially easy to do for a beginning modeler since you don’t need to deal with water or paint.

Ideas for Combining Methods

It is possible to combine some of the methods I’ve outlined here to give your brick and mortar some prototypical variation in appearance.

If you’re starting out with a model painted the color of the brick you’d like to use, you could first use colored pencils similar to the paint color on individual bricks.  This will give variation, but be sure not to create a repeating polka-dot-like pattern.  Using 2 or 3 colors of pencil over your base paint color should add a realistic effect.

You could then seal the model with  Dullcote and apply the charcoal wash (or even paint wash)  as described above.  Afterwords, you could dry brush the base color or variations of the base color over the washed building to give the bricks more aging and variation.

Each modeler has their preferred method for mortar , but hopefully this sheds some light on a technique you haven’t yet tried or seen.