In article ,
Rick Dipper writes:

I got this (below) from dyson today.

From: Darran Crook
To: '"
Subject: Dipper 31299
Date: Wed, 27 Oct 2004 14:34:09 +0100

Dear Mr Dipper

Thank you for your e-mail.

Our vacuum cleaners are designed and tested for domestic usage only. We
would not recommend picking up quantities of plaster dust or soot as this
will cause the filters to clog prematurely and may cause further problems
with your cleaner.

Please be aware that vacuuming large quantities of fine dust such as
plaster
dust or soot may require you to wash the filters more often than the
recommended 3 months.

Actually, as I wrote in another posting, they work better for
plaster dust than any other cleaner I've tried. The washable
filter will need rinsing out after perhaps 4 or 5 bin fulls of
plaster -- it's easy to see when that's required and trivial to
do. I keep two so I can use the second whilst the first dries
out. There's no plaster dust in the exhaust, and after some ~4
years, the original post motor filter (non-washable) is looking
brand new.

Soot is a different story. Soot particles are extremely fine and
sticky. They will wreck any vacuum cleaner, and there's a small
possibility they can catch fire or explode when going through
the fan motor. The best thing for soot is an old bagged cleaner
with a bag full of dust -- the soot will stick to the dust in
the bag for a while. When it gets to the bag material itself,
it will either instantly clog it, or pass straight through,
depending on the size of the pores in the bag. It will also
stick to the insides of everything, hose, attachments, etc.
Ideally, use a bagged cleaner which can take an outlet hose too,
and have it exhaust outdoors so you aren't just recirculating
the soot particles in the house. I have an old Hoover Constellation
I use for this, and two hoses.

--
Andrew Gabriel