Painting Polyurethane to Look Like Wood

Polyurethane is a very forgiving material and will readily accept all kinds of paints without being effected by the solvents and thinners commonly found in paint. In fact, polyurethane parts can be washed in thinner to remove unwanted paint, providing the parts are not soaked over night and do not have other parts attached to them that are effected by solvents, such as styrene or CA glue joints. You can even use Floquil™ stains!

While a new, unweathered paint job is easy in all modeling materials, many modelers are reluctant to move away from wood when making a highly weathered model. However, other modeling materials can be painted to look as good, if not better than wood. A good technique for achieving a weathered wood effect (on any material) can be done as follows:

Recommended Tools and Supplies:

• Fiberglass scratch brush or eraser.
• Spray painting equipment.
• Paint Colors: We have used Testors Model Masters™ Custom Enamel System and PBL Star Brand paints successfully in the past.
• Natural Wood Color: Wood, or any light tan.
• Medium Brown Color: Military Brown (FS 30117), Leather, or any dark brown.
• Medium to Light Gray: Euro I Gray (FS 36081), or any light gray.
• Your Final Paint Color.
• Weathered OverCoat: Rust, Medium Brown, or your Final Paint Color.
• Flat Finnish.
• A good quality acrylic lacquer thinner and retarder.

Caution: Use all glues, solvents, paints, and thinners in a well ventilated area. Read, understand, and follow all safety instructions accompanying these products.

The Scratch-Through Painting Technique, Step by Step:

1. Thoroughly wash all parts before painting! Paint won’t stick to oily fingerprints.
2. Paint the part with your Natural Wood Color1; and allow to dry. (This step can be skipped as polyurethane parts are already a “natural wood” color, but you are trying to match the color of new, un-weathered pine or oak.)
3. Spray the part with a thin, light coat of your Medium Brown Color2 and allow to dry.
4. Go over the part lightly with a fiberglass brush, in the direction of the wood grain, until a small amount of Wood color shows through.
5. Spray the part with a light, thin coat of your Light Gray Color2 and allow to dry.
6. Go over the part with the fiberglass brush again. Taking just a little of the gray paint off will make the part look older; taking more off will make the part look newer.
• If you wish to make the painted parts of your model look weathered, paint these parts using the technique above and then add a thin layer of the final paint color. This layer can be left as is or it can be gone over again with a fiberglass brush for an even more weathered effect.
• If you wish to make the lettering on your model (lettering on car kits, heralds on buildings, etc.) look faded or weathered, apply the decals now and over spray the area with a very fine mist of your Weathered OverCoat Color3 or the final color of your model.
7. Spray the part with Flat Finish2

Note: Be sure to thin these paints with a good quality acrylic lacquer thinner and retarder. Retarder prevents the rough, sandy finish caused by the rapid drying of the paint. Parts can be scratch brushed in 5 minutes or masked in about 30 minutes. Use the following paint formulas as indicated by the footnotes used above:

150% paint, 40% thinner, 10% retarder.
220% paint, 70% thinner, 10% retarder.
310% paint, 80% thinner, 10% retarder.

Note: Floquil™ stains can be used instead of paint.

All text, images, and drawings ©2008, Foothill Model Works.

Rev. 3/28/2014.