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aging plastic
Styrene when used to represent wood in the model world eliminates the limitations of wood. Wood has its own grain and color. Styrene is a blank palette which can be manipulated.
Click here to make plastic look like rough weathered wood
Click images to enlarge
This is an HO Atlas Trackside Shanty. It is being built to represent an 1870's oil pump house. It has been weathered with Kilz2 acrylic primer and a wash of black Rit Black fabric dye. Its construction will be covered in another piece.
(Click image to enlarge)
The look of wood gradually aging has been added using the following technique.  (Click image to enlarge)
I use a brass grill brush to give the styrene a dull texture.
Simple roughing can be done with sandpaper. Additional roughing can be applied with a hobby knife.
Kilz2 acrylic primer is used to give the plastic "tooth" for the staining with black Rit Black fabric dye. Drawing Ink in raw and burnt sienna will represent the fresh wood, this is Koh-i-noor. Mark one brush with tape to be the black brush.
The lustre is taken off the styrene with either 220 grit sand paper or the wire brush. There should be no original finish.
Add grain to the plastic, this is 50 grit sandpaper. Additional knots and checks can be added with a hobby knife.
Paint the plastic with the Kilz2 primer. It will be slightly off white and have a texture. Make sure to cover the entire piece.
Add a drop of black medium and water to the surface and scrub it around. Try to make bubbles as they will add texture
If the plastic is too light add more dye to the wet surface and swirl it around.
If the plastic is too dark add more water and suck the excess up with a brush.
The plastic when dry will look like weathered wood. The dye can be maneuvered around for other effects, but this is the plain vanilla effect.
Since the primer is stained by a small portion of the dye, the remaining pigments can be redistributed for other effects.
This is the basic styrene to weathered wood technique.
To add the effect of gradual aging raw sienna drawing ink is brushed along the area representing the original wood. Mainly under the eaves out of the sun and rain.
A tissue is used to lightly smear the raw sienna ink downward. It will remove the water soluble fabric dye. This gives a randomness to the procedure.
The light area is the raw sienna. Add a little bit of burnt sienna. About one eighth of that in the picture. Add a little water to the burnt sienna and feather it about the raw sienna area.
The sienna moving it the black is colored with that dye and makes a natural transition.
If you aren't taking pictures and use less burnt sienna it will look better than this picture. The burnt should add a subtle orange and not be so distinct in its line. This dried too quickly while I was taking pictures.
Add some black medium and gently feather it into the sienna. The black may need to be readjusted since it is water soluble it can be reworked again and again. The ink is permanent.
The finished look. It probably needs less burnt sienna unless you are representing redwood.
This aging technique only works on styrene. Wood is too porous too make the smear of ink work. I have not tried other white primers and black stains. I am sure that other combinations will get different results.
Plastic kits can be made to look like wood
Kits can be primed after assembly and weathered.
Scribed basswood primed white and mottled with black Rit dye. Note the grain problem in scribed wood sheeting.
(Click Image To Enlarge)
The MicroMark Distressing tool is really great for putting "scale" grain on styrene.
It does it quickly and has become my favorite "grainer".
An HO figure at left on a styrene "timber" portal
(Click images to Enlarge)
Click here for our weathered wood page
Black Mediums
Originally I was using liquid Rit fabric dye, but have changed over to Dye-na-flow fabric paint. Dye-na-flow black is a true "black". Most "blacks" are just concentrated blues and purples.
The Rit dye also fades on plastic. It works fine weathering wood.
The shed faded slightly after five years under florescent lighting. The tank did not, go figure. The flat car deck is still black after four years under the same light.
(Click Images to Enlarge)

The shingle paper is from Evan Designs "ModelBuilder" program.
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