This guy made a desktop jet engine made with many 3d printed parts and burning chamber made from refractory cement molded with PLA 3d printed mold. He also used a skateboard bearings, sheet metal and an electric starter, all powder with lighter fluid!?
Here is a video of the engine running and being taken apart:
Here is a test at 40k RPM:
Project homepage with complete construction manual book to be released:
If you think its very hard to make a DIY turbine jet engine you will be surprised that it was done many time even from junkyard parts like this one: