Pat Barber wrote:
Not to appear too dumb...but what is a drywall bag
and where do I get one ?

A drywall bag is simply a disposable filter bag, fine enough to contain
drywall dust. I buy them in the Shop Vac (generic term...) section,
wherever Shop Vac accessories, like filters and hoses, are sold.

I find that the bag provides a steadier suction for longer than a HEPA
filter by itself. My HEPA filters seem to clog quite readily with
sanding junk. The bags also make the job of emptying the vacuum much
cleaner, but they aren't all that cheap. Since the main use of my
vacuum is with handheld sanders, I don't worry too much about the extra
cost. The bags last me a long time.