First we have printed a number of prototypes in PLA to have an example of the structure and concept of our airship. PLA is a cheap material and printing PLA does not take so much time. After a couple improvements of the structure we could print our last and final 3D model in ABS. Acrylonitrile butadiene styrene has better heat and strength characteristics and it is also an easy material to print, it only takes a little bit longer and need more stable warmer environment to print.
By using Acetone we were able to smoothen the outer surface of the structure, this is important to improve the aerodynamics of the actual ship, but more important for us now is that it will hopefully prevent punctures of the outer nylon layer and tearing it apart that quickly, when we start with the vacuum process.
Next we made a vacuum bag from the nylon material to test if the structure would be able to handle the pressure. With the vacuum pump and components, we were able to reach a pressure of 8 millibar. With this test we have assumed that the structure can easily handle the pressure without deformation. The next step will be to measure the amount of lift we can get with the vacuum and with this knowledge it will be possible to determine how big the actual ship would have to be.