When you first begin building models, it may seem that primer is an unnecessary step. However, it is actually a critical part of the process if you want good results.
Primer basically does three things for you. First, it provides a uniform surface that allows paint to adhere better. The primer will bond to the kit and the paint will lay on the primer better than it will the uncoated plastic, resin or metal.
Secondly, that surface allows for a more realistic or natural look to your paint job. By creating a single unified color, typically gray, paint will transistion between colors better and not look different on different parts of the kit. This is especially true if your kit is made from more than one type of material.
Finally, primer exposes problems with your build up before it is too late. Pin holes, gaps and poorly fitting pieces will become apparent and you can fix them before you start applying coats of paint.
WHAT KIND OF PRIMER SHOULD I USE?
Like many things in modeling, this will ultimately come down to personal preference.
You can use sandable auto primer that you can find in large spray cans in department stores, often very inexpensively. In fact, the inexpensive no-name types are frequently better than brand name spray primers for model building.
You might prefer, however, smaller cans of primer marketed specifically for model building, especially metal kits like gaming figures. These have a tendency to do a good job on surfaces that are very smooth or very resistant to paint.
However, the best choice for many modelers is to use a liquid primer designed for airbrushes. This offers you more control, less gunk, and ultimately uses less primer. It is also much faster and makes working on small parts or sub-assemblies much easier. And, you can use gray ink or even thinned acrylic paints to prime a kit when using an airbrush as well as a commercial primer coat.
HOW TO PRIME A KIT
1. Wash your kit thoroughly in a basin with warm water and dish soap to remove oils, residue and mold release agents and allow to dry.
2. Assemble the kit in sections, setting aside parts and assemblies that will need to be done separately. For example, a tank turret should be assembled and primed separately so that the primer does not bond the turret to the hull accidentally.
3 a. SPRAY CAN PRIMERS: Hold the can approximately 8 inches from the surface of the kit and sweep back and forth in even sprays, starting a little before the kit and ending a little after the kit. Do this in a well ventilated area, preferably outdoors, and wear a mask.
Allow your coat to dry and then reposition the kit to get all angles. This may take several coats.
3 b. AIRBRUSH PRIMERS: The same basic process is used with airbrush primers, but if you are shooting through and airbrush, you can get much closer to your subject. Priming may commence only be a couple of inches from the surface if you have a light airflow and good control.
4. Study the kit for flaws like holes, gaps and poorly fitting pieces. Make corrections and re-prime the kit when done.
5. Begin applying paint when the primer has throughly dried. This will vary with the type of primer and weather conditions. If you can let it sit overnight, do so.
TIPS:
1. If you are spraying small, lightweight parts with an aerosol can, you can send them flying of into space if you are not careful. You can hold them in place with a little 2 sided tape or you can place them in a box.
2. You should anticipate the problem of repositioning the kit while priming. You can put your kit on a piece of cardboard so your fingers do not have to touch it or in some cases mount the kit to a piece of wood with a screw (for solid body resin) or double sided tape. A little glue is fine to as long as it won't damage the appearance. Consequently, you should attach the kit to a board at a point that won't be seen on the completed model.
3. You can apply primer to parts while they are still on the sprue in some cases. However, don't prime clear plastic or chrome parts and remember that there will be no primer at the point you cut off the part.
