Editing Plastic model kit (section)

==Construction and techniques==

[[Image:Plastic-model-F18.jpg|thumb|Unassembled parts of a [[Hasegawa Corporation|Hasegawa]] 1/72 [[F/A-18E]] kit. The frame surrounding the various parts is called the injection moulding "runner" or "sprue"]]
The first plastic models were injection molded in cellulose acetate (e.g. [[Frog (models)|Frog Penguin]] and [[Varney Scale Models|Varney Trains]]), but currently most plastic models are [[injection molding|injection-molded]] in [[polystyrene]], and the parts are bonded together, usually with a plastic solvent-based adhesive, although modelers may also use [[epoxy]], [[cyanoacrylate]], and [[white glue]] where their particular properties would be advantageous. While often omitted by novice modellers, specially formulated paint is sold for application to plastic models. Complex markings such as aircraft insignia or automobile body decorative details and model identification badges are typically provided with kits as [[screen-print]]ed water-slide [[decal]]s.

[[File:Gunpla decal sheet.jpg|thumb|left|Decal sheet]]
Recently, models requiring less skill, time, and/or effort have been marketed, targeted to younger or less skilled modelers as well as those who just wish to reduce the time and effort required to complete a model. One such trend has been to offer a fully detailed kit requiring normal assembly and gluing, but eliminate the often frustrating task of painting the kit by [[mold (manufacturing)|molding]] it out of colored plastic, or by supplying it pre-painted and with decals applied. Often these kits are identical to another kit supplied in normal white or gray plastic except for the colored plastic or the prepainting, thus eliminating the large expense of creating another set of molds.

Another trend which has become very extensive is to produce kits where the parts snap together, with no glue needed; sometimes the majority of the parts snap together with a few requiring glue. Often there is some simplification of detail as well; for instance, automotive kits without opening hoods and no engine detail, or sometimes opaque windows with no interior detail. These are often supplied in colored plastic, although smaller details would still require painting. Decals are usually not supplied with these but sometimes [[Polyvinyl chloride|vinyl]] stickers are provided for insignia and similar details.

[[Resin casting]] and [[vacuum forming]] are also used to produce models, or particular parts where the scale of production is not such as to support the investment required for injection molding.

[[Image:Yamato.jpg|right|thumb|Details of [[Tamiya Corporation|Tamiya]] 1/700 scale model of the [[Japanese battleship Yamato]], which is heavily detailed with aftermarket photo-etch detailing parts.]]

Plastic [[ship model]] kits typically provide [[Yarn|thread]] in several sizes and colors for the [[rigging]]. Automobile kits typically contain vinyl tires, although sometimes these are molded from polystyrene as well, particularly in very inexpensive kits. Thin metal details produced by [[photoetching]] have become popular relatively recently, both as detailing parts manufactured and sold by small businesses, and as parts of a complete kit. Detail parts of other materials are sometimes included in kits or sold separately, such as metal tubing to simulate exhaust systems, or vinyl tubing to simulate hoses or wiring.