Well, the flow bench project is comming along, finished the internal wiring yesterday and did a smoke test, both ways. First we powered each pair of vaccuum motors to verify operation, all OK. Then we closed it up and put it under vaccuum with 2 pair of motors, my shop can't power more than 2 pair at a time, and ran a cigarette past every seam, the smoke went straight up NO LEAKS!!!
We used a piece of scrap 3/8 ply to seal the input port and I almost broke it trying to lift it with the vaccuum on.