Project Hephaestus: Open Source Autoclave

Carbon fiber is a massively mystified advanced composite material that has its reputation cemented by its extraordinary performance in industries ranging from automotive and aerospace to lightweight prosthetics and cosmetics. To facilitate this material, autoclaves serves two functions:

• A vacuum chamber to degas the resin that impregnates the carbon fibers
• An oven that causes the carbon fibers to be filled with carbon nanotubes

Mission Statement:

Project Hephaestus will consist of an open source carbon fiber autoclave that uses readily available, off the shelf components that is both easy and affordable to assemble and operate. In addition, it will be made itself open source and free for anyone to download, and facilitate the use of carbon fiber to anyone.

This project initially came about as a sudden intrigue with carbon fiber as a material that can be worked with without millions of dollars worth of equipment. This idea emerged after an enlightening interview in Silicon Valley, California where I was able to see what actually occurs during the manufacture and design of the material. Thanks to my preexisting expertise with Generative Shape Design in CATIA V5 and V6 3D Experience, the evolution to composite design was relatively easy and simple to adopt. However, this left the problem with the exorbitantly priced autoclaves required to make even the smallest parts with carbon fiber. After looking at what an autoclave actually was, being effectively a vacuum chamber and an oven in the same package, I found it hard to take the 5, 6 and 7 figure prices advertised by those who sell these machines seriously.

My design began with a standard size Uline Stainless Steel 55 Gallon drum. From there, I moved outward with my design to reinforce the shell by welding ribs onto the protruding stiffeners that are already employed by the base design to reinforce the shell against the force of the vacuum within, which is known to collapse standard 55 gallon drums. The space between these ribs is filled with expanding insulation foam to reduce the heat losses of the oven through the sidewalls, and encased with another layer of thin stainless steel sheet panels which will contribute to both of the aforementioned functions.

The mechanical components are limited to basic plumbing fixtures, including flanges, 2 sizes of pipe, 2 ball valves, and a vacuum pump and gauge, all of which can be acquired from a hardware store. The heating element and control system will be that salvaged from a convection oven. The only tools required to manufacture the final product will be a pipe wrench, basic metric Allen wrenches, and a stick welder.