Cyclone separator for shop-vac for 25€

I’ve been thinking about building a cyclone separator for my shop-vac for a while now, and I finally decided to go ahead and do it. I was planning on building a Thien cyclone, and was shopping for the required buckets and bits of pipes, when something else caught my eye in the store. It was a vacuum cleaner for fireplace ashes, on special for only 25€. It had pretty much all the pieces I was going to buy anyway, and they were partially assembled the way they need to be, so I bought it.

In short: A Nilfisk shop-vac and a cheap ash-vac:

..became a shop-vac with a cyclone separator:

Building this was really simple. First I just unscrewed the motor/filter assembly from the container. After that, the only thing that actually took some doing was hacking a hole in the center of the lid, and hot-gluing the aluminum nozzle pipe in the hole as the exhaust port:

The rest of it just fit together. All the hoses and connectors were the exact correct size, like they were made for each other.

Does it work? Yes. I did a test run by cleaning up the workshop, and here are the results:

There is a small amount of fine dust in the Nilfisk’s container. All of the larger pieces and very nearly all of the fine dust are in the separator. There is naturally a decrease in the suction power, but that’s nowhere near bad enough that I’d need to even consider not using the separator.

I might consider adding the baffle in the cyclone separator later, but for now the system seems to work quite well enough without it.

All in all, for about 30 minutes of work and 25€, not bad at all!