I have a bunch of dings, cracks, and popped nails on the ceiling I've repaired, but when it became time to sand them the dust was so much worse than the walls. The dust goes everywhere and protecting the (much larger) area from the dust takes so much more work and time. I thought of attaching a vacuum to the sander would help, and those are sold, but they were around $50 so I designed and printed my own. It works well and will hold itself to the ceiling in use (channels do not exit the sides- only through the sanding pad). The only hardware you need is two M4x25mm hex bolts with two wingnuts to attach the hold downs. In case it's not obvious, this will only work with mesh drywall sanding pads.

The hold downs are very simple and based on the cheap sander I have. Lots could be improved here and holes are a bit undersized- I just drilled them out instead of dialing in the size. Inelegant, but functional.

The vacuum port is sized for my own vacuum (1.75" OD; DeWalt Stealthsonic). I hope that's a common size, if not printing an adapter shouldn't be too difficult.

I printed the bottom 5mm in TPU and the rest in PET-G (don't use PLA with TPU- it won't stick well). I used an extra full layer where the material transition occurs to make a better bond (3mf file for XL included). I also fuzzy-skinned the handles for better grip.

You could probably make it out of one material without the TPU base but you might want to use a thin mesh pad between the sandpaper and sanding pad for a little extra cushioning.