vacuum prefilter

[Stephen]

Hi,

I don't know if anyone has seen this in the cpc offer leaflet:

for some reason, it doesn't seem to be coming up at the offer price.

The description says it is for cleaning ash out of stoves. I know they vacuum a boiler at its service, though I haven't done one myself, so I wonder whether it would be useful for boilers too? Is the problem that the ash/soot is so fine it will go in one end of the vacuum and out the other unless you use a prefilter or have a very expensive vacuum?

I've read here about people making their own prefilters from a bucket, to use when wall chasing. Is this an off the shelf answer to that problem?

Hope that helps someone. Stephen.

[Andy Dingley]

I've done several of these as dust & chip collectors when woodworking. They're easy to make, effective, and well worth it. If the listed thing is solidly made, I'd pay =A320 for it, otherwise make your own.

You have two technical problems: making dust come out of suspension in the air, then keeping the dust in the can and not being picked up afterwards. The second is often harder, especially in a small can. I wouldn't try making one out of a bucket - find something taller.

The designs come in three flavours: the "drop box" (search the web for US woodworkers), the parallel cyclone and the conical cyclone (web again, there are a couple of really good sites out there).

IMHE, rubble and plaster dust can be filtered with a drop box (sharp rightangle turn and expansion of the airflow as the hose enters the box). Lightweight sawdust needs a cyclone. Conical cyclones aren't worth the trouble except as big fixed units, but simple parallel cyclones certainly are.

One useful rubble & chimney sweeeping pre-filter I use a lot is made from the old case of a dead workshop vacuum. The original side entry is blocked and new entry & exit, with a central cyclone tube, are fitted to the old lid.

[Colin Stamp]

When I vacuum my old, non-condensing, cast-iron boiler, what comes out is mostly rust and dead wildlife. Nothing that I'd call ash or soot. I use an ordinary vac and floss it with thick cord.

Cheers,

Colin.

[Tabby]

Mind if we put that on the wiki Andy? I'm sure some folk could use it.

NT

[John Rumm]

Hows the memory these days? ;-)

You added that and others last time it came up:

(might be better in a separate article on dust/chip collection)

[Tabby]

thats just a link rather than the content, unless I'm misunderstanding

NT

[John Rumm]

Sorry I thought you were proposing to use the link... my misunderstanding.

A dust collection wiki would seem like a good idea though... perhaps sections on coping with problematic tools (i.e. Wall chasers, sanders, planers etc) as well.

[Tabby]

:

Sounds good.

move next. :)

NT