by the Testors Corporation
(Testors has discontinued almost everything they made. The information here is also applicable to other brands of paint.)
Introduction
Model building is a fascinating hobby. However, the quality of the finished product will depend on your skill level and tools used. Listed below are levels indicating what finishing products and tools are required to assist you in achieving levels of expertise. As with any new learning experience, there is an entry level on which skill is built. A word to the wise: remain positive, patient and persistent so that you achieve and enjoy the satisfaction of assembling and completing models to be proud to display.
Entry Level (Occasional model builder) – Precision Cement, hobby knife, paint set, brushes.
Intermediate Level (Striving to enhance skills) – Precision cement, liquid cement, single action airbrush, propane, compressor (optional), tweezers, putty, sanding films, sprue cutter (optional), hobby knife, Model Master brushes, airbrush thinner, brush cleaner/thinner.
Advanced Level (Has achieved excellence) – Professional double action airbrush and accessories, compressor with regulator & moisture trap, above mentioned supplies, Dullcote, Glosscote, Lacquer Thinner, Model Master paints, Model Master brushes.
Enamels
To preserve your enamel paint and prevent the inner seal and cap from sticking to the bottle’s rim, we recommend that you not paint directly from the bottle. After thoroughly stirring your paint, pour out only the amount of paint you need for your project into another small container (orange juice lid, etc.), cap the bottle and paint from this container. Do not pour separated paint back into bottle. By not painting directly from the bottle, evaporation is reduced and the likelihood of having to use a thinner is decreased. Depending on the amount of thinner used, the added solvent can slightly lighten the color of the enamel.
It is important to achieve a clean seal prior to storage of the enamel. Wipe away all excess paint from around the outside bottle neck and inside the cap’s rim. While storing the enamel, invert the bottle to prevent oxygen diffusion into the bottle causing the paint to solidify. When thinning enamels for airbrushing, use only our enamel airbrush thinner. Only our enamel cleaner/thinner should be used for thinning bottled enamels. Both can be used for clean up.
To obtain the best finished film result, aerosol paint should be applied in several fine mist applications building up coverage. This procedure will reduce drips, runs and sags. Wait 5 minutes between coats. To achieve a gloss finish, your last coat should be applied heavier giving the finish a wet appearance. Do not apply paint between 3 to 48 hours of last application. Enamels are sensitive to environmental conditions. To learn more, refer to “Trouble Shooting” section.
Lacquers
Usually lacquers should not be applied over enamels due to their incompatibility with one another. However, Testor hobby lacquers are generally compatible with our enamels and acrylics in their dry state. Exceptions are noted further on.
The 1400 series of Metalized Lacquers are offered in bottled airbrush ready buffing and non-buffing coatings. Due to demand, Aluminum Plate, Stainless Steel, Magnesium, Titanium and Gunmetal colors were added in aerosol form.
Coatings should be applied in multiple fine mist applications building up a uniform coverage. When using the buffing coatings, gently rub out the dried film to achieve a gloss reflectance. When sealing the buffing colors, use Product Numbers 1409, 1459 or 1261. When necessary, test decals markings for compatibility prior to placement. Mist on applications of the sealer so as not to diminish the reflectance. A word of caution, apply a water based acrylic as the sealer over No. 1418 Aluminum.
Non-buffing coatings need to be sealed prior to the application of our enamels or acrylics. For clean up and over spray, use Product Numbers 1159 or 1419 Thinner. Use a wet mask or our no-tack masking material, Parafilm.
Glosscote and Dullcote lacquers are generally compatible with our acrylics and enamels. However, aerosol lacquer Product Numbers 1260 and 1261 should not be applied on metallic aerosol enamel Numbers 1244, 1246 and 1251. Use enamel clear overcoats instead. When applying, be aware of your environmental conditions. Too much humidity will result in blushing or hazing. Refer to the “Trouble Shooting” section. It is very important when using Dullcote that all the dulling agents are thoroughly mixed into the solvent prior to application. If not sufficiently mixed, the finish will appear as a white blotchy, snowy coating. When this occurs, the lacquer coating can be easily removed without harming the decal markings or enamel coating. Refer to the “Removal” section. No 1159 Lacquer Thinner should be used when airbrushing the lacquers and for clean up.
To enhance adhesion of our decal markings to non-painted models, we recommend that the surface first be sprayed down with Glosscote.
Troubleshooting
Modeling can be fun and interesting, but keep in mind that along with the good experiences, you will encounter problem areas. Approach these problems as positive learning experiences in developing your skill level. Some problems may show up because of how the paint was applied, when it was applied and where it was applied. Below are descriptions, causes and suggestions on how to avoid unsightly paint finishes and add to the life of the product.
Thickened Paint
The most common cause of thickened bottled paint is caused by the evaporation of the enamel solvents or water. The evaporation of the liquid is usually due to painting directly from the bottle and while the paint is in storage. When brush painting an extended time, pour out into a separate container the amount of paint required. Wipe away excess paint from around the bottle rim prior to cap placement. Invert bottle during storage. These two suggestions will reduce the evaporation process increasing the paint’s longevity. Paint will also thicken or gel when the wrong thinner is used. A word of caution: not all thinners are created equal. Use the recommended thinner for the product for the best results. Paint will also thicken or jell up when an incompatible thinner is used. Left over paint thinned with airbrush thinner should not be poured back into the original bottle.
Thin Paint
When experiencing watery, thin, low coverage bottled paint, the most common factor associated with this is the insufficient mixing of the pigment and liquid. Merely shaking the bottles will not provide the right viscosity of the paint to achieve coverage. A stir stick or brush handle should be inserted into the paint to stir the pigment into the solvent. This procedure should also be followed when nuxing paints before pouring into a cup and thinned for airbrushing.
When low coverage is experienced using aerosol paints, the two most common causes are that the substrate needs to be color neutralized or a transparent color is being used. All our Candy colors are transparent paints. If experiencing low coverage when airbrushing, usually too much thinner has been added.
Orange Peel
Orange peel is easy to spot. The finish resembles the peel of an orange. It is caused by the rapid evaporation of the solvents either while the paint is drying, or when the paint is being applied. It becomes more pronounced at higher temperatures and/or when lower humidity conditions exist. Orange peel can also happen if the aerosol paint can or airbrush is held too far away from the object being painted under conditions, when using too much thinner in an airbrush or allowing the model to dry in a spray booth with the exhaust fan on. It is usually only visible on gloss finishes. Once orange peel develops, it is necessary to remove the film and start over. Orange peel can be experienced when applying enamels, polyurethane’s and vinyl acrylic lacquers.
Self-Lifting/Wrinkling
“Self-lifting,” is a common occurrence associated with gloss finishes. The finish will resemble a spider web or a cracked mirror appearance. Self-lifting occurs when an application of paint is applied between 3 and 48 hours after the last application. To eliminate this problem, only apply subsequent coats of enamel before three hours or after 48 hours of the last application. Self-lifting can occur when applying enamels and polyurethane’s.
Fisheye
“Fisheye” is the formation of depressions or craters on the film with a black dot in the middle of the bubble. This reaction occurs when there is contamination of the paint, with the equipment or in the environment. This can be extremely difficult to isolate and eliminate the cause. Fisheye can occur on flat and gloss finishes with any product formula.
Bubbling
Bubbling is the formation of many small bubbles in dried enamel film. This can cause a gloss finish to have a dull, rough appearance. This reaction is not uncommon when applying gloss enamel solvent-based spray paints when humidity is excessively high. To reduce the chance of occurrence, spray only when relative humidity conditions are 60% or lower.
Hazing/Blushing
Hazing, associated with lacquers, appears as a cloudiness in the dried clear or pigmented film. This reaction is commonly found with lacquers when relative humidity conditions are high trapping moisture in the dried film.
If hazing develops, mist on a compatible lacquer over the film once the humidity level has decreased. The thinner dissolves the top layer of the lacquer film and allows the moisture to evaporate. The application of too much thinner will result in ruining the finish.
Runs, Sags, Drips
Runs, sags and drips are usually caused by the application of too much paint or the improper mixture of the paint. To avoid this, apply several light applications to build up coverage making sure that the bottled paint has been stirred or aerosol paint has been thoroughly shaken. Also, when applying a transparent paint, use gold, silver or copper primer as an under coat. When a primer is not applied first, usually too much paint is applied in an attempt to achieve opaque coverage ultimately causing runs, sags and drips.
Film Drying
When paint is not drying on the surface, the most common cause is that the wrong paint was applied. When painting flexible vinyl or rubber, our solvent based enamel will not dry. A water based acrylic paint should be used. Dry time on acrylics is about 15 minutes mminutes and enamels are dry to the touch between 30 minutes to 1 hour. Lacquers dry even faster. However, the environment and thickness of coats will have an impact on the amount of time it takes for the films to thoroughly dry.
Diminished Paint Adhesion
It is important to wash your model with a mild dish washing detergent to remove mold release residue from the model. If any oily substance is on the model, the finish may appear blotchy and have diminished adhesion. Adhesion will also be compromised if acrylics are over thinned.
Melted/Etched Plastic
Polystyrene plastic will distort and even melt if exposed to heat, and it will develop an etched surface appearance if certain solvents contact it. Cement should be applied sparingly to avoid melting parts, diminished adhesion and the loss of the cement’s bonding or welding characteristic. When removing paint from polystyrene, never saturate the surface with thinner. Refer to “Film Removal”.
Silvering
When dried decal markings on a model have a cloudy appearance, this is referred to as “silvering”. Silvering occurs when decal markings are placed on a flat-coated surface and air is trapped between the paint and decal marking. To eliminate this, markings must be applied to gloss coated surfaces. If pigmented flats have been used, apply No. 1261 Glosscote lacquer prior to placement of the decals. For those challenging areas, use our No. 8809 Decal Application System. “
Once the new markings are properly applied, allow them to dry for 24 hours to shrink back into their original shape and thoroughly dry out before lightly misting on several applications of the Dullcote or Glosscote. Wait about 5 minutes between coatings.
Incompatibilities
Adverse reactions are manifested by either environmental conditions or chemical incompatibilities between solvents and substrates. When mixing or applying products in their wet or dry state that are not recommended by the manufacturer, it is advantageous to test on the side for compatibility.
If experiencing enamel that isn’t drying, the substrate is probably flexible vinyl or a combination of flexible vinyl/polystyrene. Solvent-based paint will never dry on vinyl. There are no solvents or procedures that will force the enamel to dry. The only means of reversing this adverse reaction is to remove the enamel film and start over using water based acrylic.
It is important when using any solvent overcoat on decal markings to test for compatibility between the chemical sealer on the decal sheet and the solvent overcoat. Fortunately, when applying our decals supplied in our models, there is compatibility, and testing is not required. However, always lightly mist on the lacquer spray so as not to saturate and destroy even our decal markings.
When there is an incompatibility, the decals will wrinkle or bubble up once the overcoat has been applied. Should this occur, remove the markings and apply a water-based acrylic as the overcoat. Always test competitor’s decal sheets prior to the placement of the markings on the model.
Cements
Cements should be viewed as tools. No one cement is going to be able to provide the best results. For example, when cementing or bonding a long fuselage together that is slightly warped, you would require cement that doesn’t evaporate quickly. In this situation, you would not want to use a fast evaporating liquid cement. You would choose a slower drying cement that enabled you enough time to apply and brace the parts together. For this reason, we offer a variety of cements.
A word of caution: with the exception of the Clear Parts Cement and Instant Plastic Adhesive, our cement can dissolve the polystyrene when too much is applied. This is manifested by the lack of parts adhering to one another.
The reason why our polystyrene cements work so well is that the cement becomes a part of the polystyrene model. The cement welds parts together when the right amount is used. When too much cement is applied to a part, it becomes soft and once the glue dries out, the plastic becomes brittle.
If using primarily our tube cement, we now have a needle nose applicator cement (No. 8872 or 3507), that has much more control of placement. It has the same great formula. When using the tube cement, apply the cement with a toothpick.
Some hobbyists have a problem with our No. 3502 Liquid Cement in achieving adhesion. The cement should be applied by means of capillary action. Hold the parts together, apply the cement using a 0 size brush and allow the solvent to run along the seam area. The brush that you select for this application must be designated for only the cement. To help identify this brush from others and also reduce tipping over the cement bottle, break the brush handle in half. If the handles are painted and the paint dissolves in the cement, the cement will not be compromised.
Film Removal
Pactra Acrylics – Isopropyl Rubbing Alcohol and cloth removing in layers Model Master Acrylics – 50/50 mixture of Isopropyl Rubbing Alcohol and No. 50498 Cleaner and soft cloth in layers Enamels – Spray down film with Easy Off aerosol oven cleaner, after 1/2 hr. rub film under warm water. Repeat it necessary or remove in layers using enamel thinner. Using a paste car wax, light rub in circular motion with soft cloth enamel from clear parts. When removing metallic enamels, use a lacquer thinner for best results. Dullcote/Glosscote – Isopropyl Rubbing Alcohol and soft cloth in layers. Frequently change to clean areas on cloth or film build up on cloth will only smear around the film and not remove the lacquer. RC Car Racing Paints – Use a 50/50 mixture of Isopropyl Rubbing Alcohol and RC thinner with a soft cloth in layers. Very easy to craze the polycarbonate surface if too much pressure or RC thinner is used.
Decal Placement
After carefully masking clear areas, spray entire model with Testor/Model Master Clear Glosscote Lacquer (#1261, #1161 or #1961) Decals adhere best to a smooth surface and the shinier the finish the smoother it is. Allow the Gloss Clear Lacquer to dry completely before going further. Select the decals you plan to use and cut them from the decal sheet with scissors or a Testor Hobby Knife. Working with only one decal at a time, dip the decal in clear water for no more than five seconds. Remove it from the water and place on a dry paper towel for about one minute. When the decal slides easily on the backing paper, slide it to the edge of, and onto, the surface of the model with a soft Testor Model Master paintbrush or tweezers. Remember the decals are very thin and can be easily ripped. Work slowly and carefully. Once the decal is in the desired position apply a small amount of Testor Decal Set #8804. This will help the decal conform to any irregularities in the surface of the model. Allow the decal to dry undisturbed. Should you desire to purposely move it before it has dried, apply a little Decal Set to a soft brush and push the decal slowly to the desired position. When the decals are completely dry (usually 24 hours) apply a coat of Testor Glosscote (# 1261) or Testor Dullcote ( 1260) to protect the surface of the model. Now you can carefully remove the masking from the clear parts.
Decal Removal
The most effective way to remove the markings is by the application of household vinegar or Micro Scale’s Micro Sol. Allow the solvent or vinegar to soak through the decals to loosen up the adhesive (time factor could be five minutes to I hour). Periodically check the markings and when ready gently remove the decal the markings with tweezers.
Cement Removal
Any solvent that will remove the cement from a model will also destroy the model. Refer to the “Cement” section. However, nail polish remover that contains acetone will remove the cement. Blot at affected area with a clean cloth so as not to smear.
Pactra RC Car Racing Finish Paints
RC colors are vinyl acrylic lacquers that are specially formulated for flexibility on the underside of polycarbonate bodies. Overcoat the RC paints to fuel proof using Pactra’s No. 20087 Clear Varnish (high gloss). Since the Clear Varnish does have an amber tint to it, we do not recommend using the varnish over white. RC’s are sensitive to hazing/blushing. Refer to the “Potential Problems” section. When airbrushing the paint, a starting point of 9 parts paint to 1 part RC thinner is recommended.
In order to avoid the RC paint from chipping or peeling, it is important to remove all mold release residue from the surface prior to spraying or masking. Apply the paint in light applications. When the body is held under direct light, you should be able to see through the paint. If too much paint has been applied, not only does this create runs, sags, drips and bleeding under the electrical masking tape, but it also enhances the likelihood that the paint will pull away from the polycarbonate.
Reprinted with permission of Testor Corporation 620 Buckbee St Rockford IL 61104. All Rights Reserved.