Sorry, but a shop vac is like using a 4 cylinder in a semi truck. It won't get near as much of the dust that you need it to get out. I would strongly recommend getting one of the larger dust collectors. I would also recommend one of the air scrubber systems. I run a larger dust collection system while I am turning and sanding and run a jet air scrubber that I have put on a movable cart for when I am sanding or doing anything that is creating dust. The big plus of the air scrubber is that it moves a lot of air and filters down to 1 micron which is small enough to go directly into the lungs and create some major health problems. Wood dust can be very toxic to breathe in and can cause many problems such as cancer, emphasema, and other lung diseases. I would do it for your health and not just to keep the garage clean, that is just a bonus.