On 18/04/2019 22:54, dennis@home wrote:

I doubt if fine dust will block the cyclone but there may be other
filters that it does.


Things may well be different for the OPs DC54 but fine powder like
plaster dust can seriously clog the cyclones on our DC08. And I don't
mean raw plaster getting wet and setting. Sucking up lots of brick and
plaster dust after bashing out bits of walls is a sure way to end up
with blockages. I suspect it's some sort of electrostatic effect causing
the fine particles to stick to the cyclone surface. The fluffy powdery
coating on the bores of the cyclones builds up and appears to reduce the
spinning effect on the airflow with the result that much of the fine
dust doesn't get centrifuged out and passes straight through to block
the filter.

After some building work our DC08 got to the state that the filter
needed washing after every use. Completely stripping down and cleaning
the cyclone following the instructions in
https://www.youtube.com/watch?v=sB7kIL6SGiY restored the performance
back to new condition.