I have added a fine dust filter (looks like a household vag bag) to my shop vac...actually I've been usige one since I skim coated plaster walls...the filter bags are good enought to trap taping compound dust....they'll hold cedar dust.

: pete- i attach my ros to my shop vac and still have a dusty shop(garage). i
: think most of it comes from the exhaust on the vaccum.cedar dust is so
: fine it will go around the filter. all in all though its much better than
: nothing.a word of caution, if you start to hear the vac motor start to
: labor make sure you clean the filter