In article ,
Stephen writes:
Hello,

I have been using my Earlex vacuum connected to my wall chaser. I use
the dust bags which I have bought from Earlex (are generic ones just
as good?).

The Earlex web site says their bags filter to 5 microns. I have found
that when I do the first chase, the vacuum seems to suck up
everything.

I noticed that as I do more chases, more dust begins to fall from the
chaser, escaping the vacuum. I assume the bag clogs up. I think it
would be extravagant to change the bag every time I start a new chase!

That said, I can't grumble because the amount of dust falling is tiny
compared to not having the vacuum on at all. I forgot to put the hose
on the other day and there really was a difference!

The bag was getting heavy the other day so I emptied it and it was
full of fine dust, so it is certainly doing a good job but I remember
a thread here where someone said the only vacuum he found that could
cope with repeated wall chasing was a Dyson. Looking on line, it seems
the Dysons filter to 0.1 micron, so would capture even more.

Should I be content with what I have got or is it worth getting a
second hand Dyson just for this?

As you've discovered, a bagged cleaner is useless for the volume
and rate of dust generated by a wall chaser. You have to use
something which keeps the collected dust out of the air path.

If so, is there any particular Dyson? I seem to remember DC04 and DC07
being mentioned before. What are the differences between them? Does it
have to be an upright?

I've used a DC04 and DC07. Both work well. The DC07 is a more
recent and powerful model, but it has more smaller channels
which can get blocked by house dust if the thing has been
used with a grossly over-fulled dust container. Dust from the
wall chaser won't block them, but if the cleaner is of unknown
origin, I would dissasemble the top and blow the channels clear
before you start. Check the washable pre-motor filter too and
let it dry if it needed washing. (I've never had the post motor
filters on any of the family's Dysons get dirty -- I think you
would have to abuse very badly to do do that, such as grossly
over-fulled dust container whilst also removing the pre-motor
filter.

The dust canister will be very heavy when full of plaster/brick
dust, heavier than the handle is designed for, so beware of that.
The brick dust will also sand-blast the inside of the canister,
which doesn't affect operation, but SWMBO might not be happy
that it no longer looks like new.

Keep an eye on the pre-motor filter. Providing you don't grossly
over-fill the canister, it should last a day's chasing (many
canister empties). Rinse and leave to dry overnight. (I bought a
second one so I could swap them whilst one is drying.)

I think someone mentioned making a prefilter from a bucket. That's a
good idea. Does it work just as well? My only worry is that with two
hoses, one prefilter, and one vacuum, that's quite a lot of things to
get in the way and trip over.

If you're stuck with a bagged cleaner, interposing a cyclone
before the bag will help. Constructing a cyclone which really
separates out the finest dust isn't easy and it's this that
either cloggs or passes right through the bag, although the
type of dust (heavy) involved here is the best for cyclonic
separation. Other thing I would suggest for a non-Dyson cleaner
would be make sure the air outlet is directed outside, if you
don't want the house filled with fine dust. (Dyson traps all
that, so not an issue in this case.)

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]