You may be asking, "what is a filler and why do I need it?" First, why? To built models, where someone commit¬ted half a tube of glue to the premise that more is better. "That part won't stay on . . . use more glue!" Little did this fellow realize that glue isn't stickum. He's reinforced chronically broken parts and bridged gaps between poorly fitting parts with tube glue. Ex¬cess glue will only melt and distort the plastic, ruining the model. Tube glue should never be used as a filler — we'll discuss what you should use later in this lesson.
Epoxy is a two-part adhesive which can bond almost anything and works best for mating dissimilar materials such as metal to wood, plastic to metal, and so forth. Equal amounts of the two parts are mixed, starting a chemical remold plastic kits, manufacturers must divide the model into parts. When we build the model, we reverse the pro¬cess, but the seams between the parts are often visible. Sometimes that's okay, but in most cases, the seams are ugly — they should be eliminated to produce a realistic replica.
The best way to eliminate seams is to improve poor-fitting joints. When that fails, the gaps can be hidden with filler. A filler is a soft, pliable substance that can be poured or pushed into gaps and surface imperfections. After the filler sets, excess material is sanded away, leveling the surface and concealing the gaps and sinkholes (depressions caused by insufficient plastic in moldings).
Many different fillers are available, including auto body fillers, epoxy putty, and even spackling paste. But my fa¬vorite is gap-filling super glue used with accelerator, Fig. 3.
As with any filler, there is good news and bad news about super glue. The bad news is that (if improperly used) it bonds skin together instantly. Also, some people experience eye, nose, and throat irritation from the fumes. I've never had problems, but I know model¬ers who refuse to use super glue be¬cause of this.
There's no arguing about the useful¬ness of super glues, though. I use them with a spray accelerator. Apply a little super glue to a seam or sinkhole, spray on accelerator, and the glue sets in sec¬onds. More applications of glue and ac¬celerator fill the imperfections, and you're ready to sand.
Super glue bonds to the surface of just about any material. Cured super glue is slightly harder than styrene but can be sanded easily, and, best of all, you only have to wait about a minute before sanding. Large amounts of super glue will shrink slightly when setting, but you'll be able to determine the degree of shrinkage right away and add more to correct it. Unlike other fillers, you can fill, sand, prime, inspect, fill, and sand again all in one modeling ses¬sion — no more waiting a few days for filler to dry.