The art of scratchbuilding is that of building a model or its parts from simpler materials. Any materials may be used. It is in some sense a very advanced kitbash technique.
The line between scratchbuild and kitbash is sometimes fuzzy. For example, John Spangler's Steelskin project uses part of a G1 Sideswipe figure as its frame, but consists mostly of custom-built parts. So, the toy was not entirely built from scratch, but the premade parts are so heavily modified that calling it a kitbash does not really do it justice.
Don Figueroa, widely known now as a Transformers comic artist, created a great number of scratchbuilt toys from acrylic plastic (Plexiglass) during his days as a lowly fan. These toys were based on his fan comic, Macromasters.
A plastic called Styrene is commonly used for kitbashing and is usually found at hobby shops in the form of raw, white sheets. Though not as strong as factory ABS it is however very user friendly and is easily scored, cut, sanded, glued, and painted. Styrene also comes in an enormous variety of sizes and shapes such as rods, squares, half-cirle rods, I-beams, just about any shape a customizer needs to create their project with.
Redline's War Within Prime Tutorial shows what a skilled customizer can do with styrene as he built an entirely transformable figure primaritly out of the material.
A different way to produce parts for a scratchbuild is to use a 2-part casting resin poured into a silicon mold. A common casting resin used is Alumilite because of its ease of use and strength when cured. However one must first make the original piece to be molded and then create the mold around that using RTV Silicon. Headcasts of various Transformers are often duplicated this way so a customizer does not need to destroy an original figure, only make a casting of a part.
- Macromasters - An archive of Don Figueroa's fancomic and photos of his scratchbuilt toys.
- Radicons -Tutorials and 'How To' guides for scratchbuilding Transformers.