Dyes for plastics can be obtained in all colors and are a useful aid to the craftsman seeking decorative effects. The actual job of dyeing is simple - just dip the plastic, let it soak from 1 to 5 minutes, depending on depth of color desired, and then rinse in running water. Although the dye is a surface coat, it bonds perfectly.
The dye vat can be any kind of tall can or a glass tubler. A metal tube, flattened as in Fig. 2, is useful for dipping long strips. A coarse metal screen, Fig. 1, keeps the plastic clear of the container bottom. Dyes can be rebottled and used repeatedly. However, the dye evaporates very quickly in an open dish. Keep it away from an open flame when using.
Although over-all colors are the most practical, it is possible to obtain two-tone effects by masking. Fig. 3 shows a plastic square masked by dragging liquid glue across it to form a pattern. After dyeing, the glue washes off in the water rinse, exposing the pattern as in Fig. 4. Silhouettes and straight lines can be similarly worked, thinning the glue as needed. Paper masking tapes are not suitable as the dye seeps under the edges. A special masking tape is available which is designed to avoid this fault.
Dyes are easily made as in Figs. 5, 6 and 7. Just use a drypowder stain soluble in oil, the same product that is used in making wood stains. Mahogany makes a nice red; walnut a clear yellow. If prepared plastic dyes are used, they should be straight colors: oil red, oil blue, oil green, etc. Excess stain and impurities are filtered out, Fig. 8. Most drugstores carry filter paper and acetone.
Laminating dyes are made by dissolving a few shavings of thermoplastic in 1C cement which is used in cementing this "glass" product. Then add oil stain for color. This product cements and dyes in one operation and is particularly good for mottles as shown in Fig. 8. The various colors should be streaked on with a matchstick, Fig. 9. They probably will dry before the job is complete, but are redissolved by quickly applying a generous portion of clear cement - heavy type with shavings added - to the center of the work, after which the top piece is pressed in place. Squeeze gently to spread the cement adn force out air bubbles. If clamping pressure is used it should be very light.
Dye inlays can be worked with plain dye by using a glue mask as already described, or by using the laminaring dye. The latter can be masked off to a sharp, clean edge. Finished inlay, Fig. 10, is perfectly bonded. The original paper cover on plastic can be used as a mask, cuttig out the desired figure with a stencil knife, Fig. 11. Colored dye-cement must be applied by flow-coating, as shown in Fig. 12. It is impossible to spray or brush the material because of rapid drying. Thus applied, the design will be translucent and will have a gloss equal to the plastic.
Concentrated dyes which can be mixed with 8 to 12 parts of water are available and are useful for certain types of work. Application requires heating the dye bath to about 190 deg. and then immersing the work for 1 to 5 min., depending on depth of color desired. However, heat of the dye bath tends to warp the plastic. For most craftwork the chemical dyes are preferable.
In general, work to be dyed can be colored before or after assembly. If dyed before assembly, the pieces should be cut to net size. If any color effect is unsatisfactory, remove it by using a clear dip of acetone and water. Similarly, if a two-tone effect is wanted, the piece can be dyed one color all over, then dipped in a second color which will strip the first coat and deposit the second on exposed areas. An instant dip and rinse will color sanded edges.
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