This was our initial venture into making dirt horse roads with tile grout coloring and latex paint. I use a base latex paint in the color I want for the ground cover. This was the basis of scenery guru Dave Frary's water based scenery.
"Googling" images I found these nice pictures. Use advanced search and search for "grayscale" pictures. That will bring up the vintage photos.
A product called Spectra Lock Mini Unit Part C Color Powder #1218 Saturene supplies our texture. It is available at Lowe's. It is mixed with your base latex paint.
Add the color powder to the latex paint until it is the texture of wet beach sand. The mix should be gritty.
Spread the mixture onto a piece of newpaper. Break the pieces up as the mixture dries. This mix dried before I could break the pieces into smaller ones. They can be crushed later. It takes about two weeks for the mix to dry.
Now I know what yer thinkin' "Why not use regular tile grout, it's easier to find?".
That won't work the glue in the grout mixture hardens into one big glob.
The larger clods can be broken by rolling them in your fingers or crushed with a spoon. Spread the "dirt" over the road area.
If the clods are too large crush them by scraping them along with a spoon.
Arrange the roadway with a soft brush.
Initially I tried to make wagon wheel tracks with model wheel. They wouldn't make those distinct wagon tracks found in old photos. I tried to make them more distinct with a spoon handle.
The dirt was glued down with 50/50 white glue and water after being sprayed with water with a little detergent.
The road looked like it was old and had been rained on. The wagon tracks were too rounded.
I experimented with the spoon handle to make the wagon tracks look new. It worked but making them parallel with the spoon handle was difficult.
I made this tracker from a block of wood and two pieces of metal. The metal is the width of the wagon wheel. They are the wheel tread of our stage coach. I made a second with a narrower width of my freight wagon. Round off the corners.
Here we are putting tracks in the road. Drag the tracker down the road. Press enough to depress the clod mixture. We are not trying to remove the clod mixture but compress the surface. The tracks should be very light but distinct not really ruts.
Missplaced tracks can be filled with clod mixture and glued down.
Track the road with several tracks. Any funny areas can be filled with mixture and redone. I use my spoon handle to accentuate the too shallow track areas.
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