I just started a new project in  building a new quad frame for under $10. I started with 2" black PVC pipe and .75" white PVC. Cut all the parts to 18" and the legs at 5.5". I could use some suggestions on how to mount the motors. I have a old x525 with the aluminum motor mounts. I have run wire though the arms and will start to put the APM  and power board in.