This incredibly small V-12 engine is powered by compressed air. All the parts are hand-made except for the bolts. For those who don’t know Spanish:
“A tiny V-12 engine with compressed air injection, hand made using traditional methods. It is 12cc in displacement, the diameter of the cylinder is 11.3 mm, the stroke of the pistons 10mm and it works with only 0.1kg/cm2 pressure. It is constructed of stainless steel, aluminum and bronze. Patelo dedicates this engine to his grandchildren: Sara, Carmen, Jose and Pablo.”
Rust bluing is one of a number of ways to produce a protective finish on gun parts. It requires more work than the others but it provides better rust and corrosion resistance. The Pilkington Classic American Rust Blue solution used in this video can be bought from a number of suppliers.