Roads for Your Model Railroad Layout or Diorama, the SMARTT Way

Almost every model railroad has villages and towns spotted across its landscape. What lends an air of reality to these features is the road work connecting them, turning a bunch of houses and shops and industrial structures into a living town that is a part of a larger world.  It may be tempting to just slap a coat of black paint on the bare wood of your tabletop layout surface and call it done, but the process involved in making a visually appealing road is not difficult or expensive. Many roads are asphalt based and this is an easy way for model railroaders to connect their towns.

I wrote this column for our December newsletter, http://www.smarttinc.com/content/newsletter-december-2011 , free for everyone to read and enjoy.

Step 1: Sketch Out the Road

Let’s focus on a road across a relatively flat area. Draw your road to connect the two points you want to connect on the surface of your layout.  If your layout is an open grid (no hard surface except under the tracks), you will need to attach a flat substrate like plywood, preferably screwing it into place with flat head screws that will sink flush to the layout’s surface. Don’t use something that will flex easily. Make your road as wide as you need using a scale vehicle for reference. A lane of traffic will be about 20 percent wider than a car. Multiply this by the number of lanes you want your road to have.  A meandering country road may have only one or two lanes. A highway would have more. You can also leave space on a city street for a parking lane on one or both sides of the street. Add a little extra width to your country roads to allow for a dirt shoulder. For this instructable, we'll make a sample road.

Step 2: Lay the Joint Compound to Create the Road

It’s easier to make your road surface before the ground cover in the surrounding area is installed, because the road process will raise some dust that might ruin your efforts.  The first layer of the road will be joint compound, usually used to cover or fix small holes or irregularities on drywall. It is available as an air drying pre-mixed substance in a tub or as a powder you mix yourself. We prefer the powder as it chemically sets, not air dries. Depending on the one you choose, it may set in as little as 20 minutes or as long as overnight.  You will need a flat spatula to apply the compound along the length of the road in the area you have marked. Do not work in too large an area at a single time, no more than a few feet. Mix the powder by adding it a few ounces at a time to a mixing cup holding a few ounces of water. Add more powder and keep mixing until it is the consistency of thick sour cream. If it gets too thick, add a few spoonfuls of water. Using the spatula, spread the material smoothly and not too thickly (no more than 1/16 to 1/8 inch thick). Try to remove any lumps. If you have mixed the compound well, there should not be any lumps. Don’t worry if there are a few minor scratches or other imperfections in the road surface. Let this dry, overnight if necessary.

Step 3: Sand the Road Surface

When dry, sand the surface of the road with 150-220 grit sandpaper. This will create a lot of dust so have a vacuum, preferable a shop-vac ready. Make sure that the shop vac is positioned so that the outgoing air doesn’t blow the sanding dust back in your face. Wear a dust mask and safety glasses if you can. You are going to smooth the road as much as possible, then vacuum again.

Apply a second thin coat of joint compound to fill the scratches and dips of your road. It does not need to be super perfect as real roads rarely are, but make it as smooth as you will be satisfied with. Let dry, then sand and vacuum again.

Step 4: Paint the Road Surface

Time for paint. For an asphalt color, try Woodland Scenics’ Asphalt water base paint. Brush it on and let it dry. You may need two coats. For a concrete road surface, Woodland Scenic makes a good Concrete paint too.  Before you paint, be sure that there is no dust left on the surface. You may want to wipe the surface with an alcohol dampened cloth or paper towel. If you don’t remove the dust, the paint will stick to it and not the road surface beneath, and the paint may peel up in subsequent steps.

Step 5: Dry-brush the Road Surface

Now you will need some white water-based craft paint, like that made by Apple Barrel or Deco-art. Spread the paint on a piece of scrap cardboard and dip the tip of a broad soft flat ended brush in the paint. Next, scrub the brush back and forth on a clean paper towel until there is almost nothing left on the brush to come off onto the paper towel. Stroke the brush back and forth on the road surface. It should leave a light layer of the white paint on the asphalt surface, lightening it, by catching the high points of the paint surface. The more times you repeat this step, the lighter and more weathered the road will become. This technique is known as “dry-brushing.” Some people scrub in a circular pattern others will go back and forth. Choose the procedure that is most comfortable and provides the most pleasing result. If you’re unsatisfied, you can always repaint the asphalt and begin again. Cover the entire road this way and let the whole area dry thoroughly

Step 6: Mask for Road Lines

If your road will have lines separating the lanes, you will need some narrow strips of masking tape. Many people lay out regular tape on a piece of glass and use a hobby knife to cut thin strips. If you are near an auto paint supplier, you can buy rolls of tape that is already very narrow.

If you are cutting your own strips from wider tape, you may want to consider using Scotch brand low-tack blue tape sold in the paint department of the hardware store. If you only have regular white or yellow masking tape, you can reduce the tack or stickiness by putting the sticky side of the strip on your shirt before laying it out on the road.

Lay the strips of tape out on either side of your road’s center line leaving 1/16 to 1/32 open space between. Fill the areas outside the tape with more tape so that only the area where the line will be is visible. Don’t press the tape down any harder than you need to in order to get it to stay in place. When you remove the tape later it might pull up your asphalt paint layer below. If the strip will be a dashed line, lay cross strips of tape to mask for that.

Step 7: Paint the Road Lines

Depending on the era and location, your lines may be yellow or white. Check photo references for this if available. Dip a brush in the line colored paint, using the same type of paint that you earlier dry-brushed. Wipe most of the paint off the brush. If you put too much paint down, it will seep under the tape. This technique is almost the same as the dry-brushing earlier, but with a little more paint on the brush. You will only concentrate on the exposed area between the tape strips. The masking will keep you from getting paint on the rest of the road.

After your road line is dry, gently peel back the masking tape. If you have avoided pressing down too hard and if your tape is not too tacky, then the asphalt should not peel up too. If you do have a few peeled spots, just touch up the asphalt and dry-brush the area again.

Step 8: Conclusion

A little sand or fine ballast blends the edges of the road into the surrounding terrain.

This technique is pretty easy and yields great results, but you might want to try it out several times on scrap areas before heading to the layout to perfect your technique.

Applying the same idea, you can now create other paved areas, parking lots, cul-de-sacs, etc.  By more complex use of the masking tape, you can make other markings like stop-lines, Railroad crossings, and more.

Good luck and now let’s hit the road!