BUILDING MODELS

In this article we'll explain the preliminary steps we’ve come to follow in the process of building models. Some of these were born from experience, many others were taken from various published sources - in particular, FineScale Modeler magazine - and still others from talking with fellow modelers. Modeling is a great hobby in which to share your experience with others. The techniques included here have worked for us and we feel they are more or less common to every modeling project.

Step one, of course is to buy the model. The best prices are usually found on the dealer’s tables at model contests, or even on the Internet but we try to support our local hobby shops whenever we can. Check the kit to ensure that all the parts, decals, instructions, etc. have been included and are in good shape. During this process, a preliminary acquaintance with the construction procedure of the kit can be made. Often, this is the point where one determines whether to build the kit out-of-the-box, or to customize the model in some way.

Some kits require the accumulation of research materials, such as books, drawings, Internet web-sites, videotapes, etc., for data needed to make the model more accurate or realistic. There’s no shame in building a kit out-of-box but there comes a special pride in customizing the kit to make it more realistic or to make it more dynamic or eye-catching. Often, only small changes can make a dramatic difference in the final outcome, which can prove beneficial if you decide to compete with your models.

As many of you who have been in this hobby for any length of time know, months or years of the model sitting on a shelf often precede the actual construction of the kit. You know the saying: "So many models, so little time". Construction begins by removing the pieces from the sprue trees. In order to avoid damaging parts, it’s best to cut them from the trees with a hobby knife or sprue cutter rather than twisting the parts off.

For styrene kits, begin with carefully fitting the parts. We recommend sanding them with relatively rough (100 grit) sandpaper to try to get the best fit. On re-releases of older kits you may need to remove the locator pins, as they can actually misalign the parts. The adhesive of choice for us these days tends to be liquid cement for injection-molded kits. One very good product is Tenax-7R (space age plastic welder). Carefully align the parts then apply Tenax-7R to the joint. Capillary action will let the adhesive travel down the joint. If enough adhesive is applied you’ll get a bead of liquefied plastic to ooze out along the seam. This gives evidence of a solid join, plus it’s easier to trim the bead down and sand it smooth than to fill a gap with putty. When putty is necessary, there are many brands made for plastic models that are readily available at most hobby outlets and come ready to use out of the tube. These putties can be used for small fixes on vinyl and resin models also.

For vinyl kits, warming the parts in hot water or with a hairdryer will make it far easier (and safer!) to trim the excess vinyl away from the parts. A sharp hobby knife is essential for this operation, as is patience - you need to trim slowly so that you don't cut off more vinyl than you should have

Resin kits require a different for of prep work, namely a good scrubbing in warm water with soap and on old toothbrush. This will remove any mold release agents or any other residues that could interfere with the adhesion of cements and paints (actually, this is a good first step for any sort of plastic model). Small voids in the surface of a resin kit, called pinholes, may have left when bubbles formed in the poured resin. These can be filled with a variety of materials, from hobby putties to super glue. Mold parting lines or flash, created at the join between the molds in which the part was formed, can be sanded, filed, or scribed off with a knife. Pour stubs form at the point where the resin was poured into the mold, and often may need to be sawn off with a razor or jewelers saw; this operation can be risky for very small parts because resin is usually quite brittle.

To cement vinyl and resin models you'll need to use super glue or epoxy adhesives. On vinyl kits it often helps to warm the parts to be joined with either hot water or a hair dryer. This helps take out the stiffness and makes for a better join. Since there is no dissolving the vinyl or resin plastic material itself, seams and gaps must be filled.

A fine-grained, two-part epoxy putty works very well for most seam/gap filling purposes. Most brands can be smoothed with water during their working time, don’t shrink, sand easily, and bond well to every plastic we’ve used them on so far. They are especially good for sculpting new features on your model. The down side is, epoxy putties are expensive and sometimes hard to find, compared to the familiar tube-type hobby fillers.

Where a fine surface is not needed from an epoxy putty, there are cheaper brands that can be found in your local hardware store in the plumbing section. Often, this type of putty in sold in 2 stick packages where you cut off equal sections of each, knead them together until a uniform color is achieved. This type of putty has the same properties as its finer hobby counterparts, but may have less working time before it begins to cure. The advantages include price and availability.

Frequently you’ll end up with extra putty left over. You don't want to waste the expensive material, so what to do with it? Simple, with a little forethought you may have another model project to which you can add the putty. if it has begun to cure to the point that you can't add fine detail you can still use it to mold simple shapes like rocks, tree limbs, ground work etc.

Sanding is the next step - the most tedious part of plastic model building. It seems to take forever. But a smooth, scratch and seam free model is a must, particularly for the competitive modeler. It’s helpful to have an assortment of file types handy when sanding your model. Round files, angled files all help impart that precious detail back into your puttied seam line that helps eliminate them from view once painted. After you’ve sanded the seam don’t let your eyes be deceived. A useful trick is to run a silver paint marker over the puttied area. The metallic paint will quickly reveal any flaws, which can then be removed before the process of painting has begun. Still, these flaws may turn up when the primer coat goes on the model. If they do there’s really nothing else you can do except sand off the primer, re-putty, and begin again. Depending on the seam location, you could leave it as is and hope you can disguise it with careful painting techniques.

Preparation of the model for painting comes when you’re finally happy (or can live with) the sanding job. The model is washed in a soap solution and warm water. This removes skin oils, release agents, anything else that might prohibit the adhesion of the paint to the model. When dry, the surface is liberally coated with Floquil’s Poly Prep or similar product, such as common rubbing alcohol. These preparations help reduce static electricity on the surface of the model to reduce its attraction of lint, hair, and other airborne debris. Once cleaned and prepped we recommend handling the model using rubber gloves to avoid "gumming up" the surface again.

Priming is recommended before the finish coats are applied; there are good ones to be had from the hardware store and some builders swear by using auto body primer. Priming accomplishes three things:

1. As stated above, the even color provided by a primer makes it much easier to spot any construction flaws that might otherwise become apparent under your color coats. Better to have to remove a little primer to fix the problem than be forced to ruin a carefully-applied airbrush job. Don't be discouraged if you find yourself getting stuck in what can seem to be an endless cycle of priming, finding a problem, sanding off the primer, fixing the problem, washing the model, priming again, discovering the problem still wasn't fixed, removing the primer again, and so on. This can and does happen to the best modelers!
2. The various materials with which you constructed your model - the plastic itself, any fillers, and possibly aftermarket parts or other extras that were made from different substances than your kit - may look different under the finish paints. A coat of primer provides a uniform surface over which the color coats are applied.
3. Primers are formulated specifically to adhere to most surfaces. At the same time the primer gives the paint a good surface to which to cling.

After priming, you may need to mask off certain areas when applying the final painting scheme. There are a wide number of masking materials to do the job. Masking tape has its uses, but doesn’t work well in small areas or complex curves. Be careful, as the tape adhesive can pull paint off the model as well. Parafilm-M works well on compound curves, but is tricky to use. It also seems to have a limited shelf life. Micro Mask can be brushed about anywhere, but it’s hard to tell if absolutely ALL of the desired area has been covered. One coat is all that’s required. It’s a good idea to paint well beyond the line of demarcation, so that there’s plenty of dried material to start pulling the mask off with. This stuff can be treacherous, too - it can stick where you don’t want it, or pull away from the places you do. A combination of these materials can be effective.

Finally after all that work you can begin the actual painting process. There are many brands to choose from so experiment with them to see which ones work best for you. Mark stands by good old Testors paints (the solvent-based line) as the number one choice for finishing models. They’ve added color-matched military colors and acrylic formulas to these, so there’s plenty of choices for every application. Ken prefers the acrylics because of their easy soap and water clean-up and their smell isn’t as strong. Remember that all paints give off noxious fumes so good ventilation should be part of every modeler’s work area. As for the application tools, we use an airbrush to cover the larger areas or to apply the basic colors. Plan on having plenty of bristle brushes on hand for adding details, weathering, drybrushing textures and the like. Again, experimentation is the key to find the best tools and paint for your particular interests and abilities.

Spray cans of hobby paint provide quick, smooth coverage, but are usually pretty expensive. We've found that hardware store brands like Krylon work every bit as well and are much more economical. Who cares who made the paint when all you're using is flat black?

After the model has been painted, decide what type of final protective coating to use. A gloss coating is to prevent the decals, if used, from silvering. There are a number of setting solutions and solvents on the market, which soften the decal film, so that it conforms tightly to the surface of the model as well as paint. The decals are allowed to dry thoroughly, then are over sprayed with whatever clear finish will provide the appropriate sheen to the finished model. A dull coat can be used to eliminate the "glossiness" of the model, and is often used for figures, or even a satin coat for somewhere in between.

Although we have made this the final step of this construction outline, often it’s one of the first things we need to deal with. Sometimes, as with most all of the Aurora figures or the AMT Star Trek vehicles, a kit will include a nice base to support the model. We find it helpful and appealing to add a wooden base for the kit base to rest on as well. The wooden craft plaque display base does four things; it provides a stable support for the model, allows inquiring minds to examine the model closely without actually getting their fingers on it, identifies the owner of the model, and just plain makes for a better appearance (especially on contest tables).

Before work begins on the kit base, we’ll trace a paper template of its outline. The template makes it easy to find the craft plaque that best accommodates the size and shape of the kit base. These bases are stained and finished with a high gloss urethane finish. A business card or other label, with the completion date written on it, gets glued to the underside of the base, then is varnished over (we’ve read about the rare instance of models disappearing from contest tables; this label could aid in the return of a "lost" model to it’s rightful owner). Generally, the model kit base is adhered to the craft plaque display base with 5-minute epoxy.  Finally, we add felt feet under the bases, to protect the surface on which the base is resting, and to give room for the fingers when lifting the model from the table.

An alternative to a wooden craft plaques would be a trophy or award plaque. They can be purchased from bowling trophy shops, usually for the price of the raw wood hobby store plaque. The award plaques come prefinished, which is a great time and money saver. You may even find that over time, you have a few model competition awards too many. The metal label is often attached to the trophy plaque only with two-sided tape. If you remove the label carefully, you'll have a ready-made base for your next trophy magnet!