Dust extraction filter upgrade - Pledge drive

tl:dr - pledge drive for £215 for an upgrade to the woodwork dust extraction by changing the filter from a fabric dust ‘sock’ to a cartridge filter. This would lower filtration to 1 micron and improve air flow.

Pledges so far:
Frank £30
Guy £20

Total: £50
Remaining: £165

Hi all

As many will know I’ve been working on the dust extraction system for the woodwork tools along the main work bench as well as the larger tools including the Table Saw and Planer Thicknesser. The system has been built to extract dust in two stages:

  1. First large chips and dust is removed from the airflow in the large wheelie bin using a thien baffle made at the space. This was recently we emptied it for the first time after having it running for 8 months. The process was quick and simple with the bag taken to the tip and disposed of as bagged waste.
  2. The second stage is after the fan with the fabric dust ‘sock’ where the finer dust particles are removed and is the subject of this pledge drive. Seen in the photo below with the ‘Clarke Woodworker’ logo on it.

As this system build has been progressing, I’ve been looking at ways we can improve the system. One of the most significant improvements would be to change the ‘sock’ filter to a cartridge filter instead as they can achieve even better filtration level and higher airflow.

Dust socks are typically rated to only filter down to 5 microns, while a cartridge filter can achieve 1 micron. The reason this is significant is that for some materials like MDF, they typically have a particle size of 2-3 micron, and any fine sanding will also produce sub 5 micron particles making the dust sock largely ineffective.

As the sock also acts as the storage bag for the finer dust, over time as this fills up less surface area is available for filtering and in turn this lowers the air flow. With the cartridge filter setup the dust falls into a separate bag ensuring the surface area is kept clear.

To incorporate a cartridge filter improvement to the system we would need to buy a few items first:

  1. Cartridge filter - £159.00
    There are typically two sizes of cartridge filters commercially available, 370mm (15") and 500mm (20") diameter. For cost purposes I’ve gone with the smaller as the reduction in size is still sufficient for our current extraction fan size (1hp) (500mm dia = £219).
    If we were to upgrade the fan in future we’d simply just buy a second 370mm if required.
    The Charnwood filter linked above has a built-in cleaning device that helps ensure the filter fins are clear of dust and not clogged. If you’ve cleaned a hoover before you’ll know seeing dust in the filter fins is a common occurrence and a hassle to clean.

  2. Collector body - £45.64
    From extractor W696, part number #41
    The collector body is the metal cylinder highlighted in the red box in picture at the bottom of this post. This isn’t typically sold individually but by ringing Charnwood I was given a quote for buying just the body as a spare part.
    Without this we would have to build our own to attach the filter & dust bags to. And while that is certainly possible. IMO for the price for a prebuilt option that would work out the box it seems good value.

  3. Dust bags - £9 for pack of 10
    As the filter isn’t intended to hold the dust, a bag is installed underneath to catch the dust. These bags would allow us to easily collect and dispose of the fine dust just like the wheelie bin.
    Currently we have to remove the dust sock and empty it into another bag. For those who’ve emptied the sock in the past, they’ll understand how difficult and messy/dusty this is and typically needs to be done outside.
    The plastic bags would be an on-going consumable, however as the bag is for the secondary filter it is likely to fill much slower than the wheelie bin.

As these items come to a total of £213.64, I am asking for this to be a pledge drive as I’ve already spent a great deal on the system so far personally. If you’d be happy to contribute, please reply with the amount and you’re Name/telegram handle if you have one below.

I’ve asked the board to facilitate the finances of this, so once the total is achieved monies would need to be sent to the space account first before anything is purchased.


Image of default 1hp extraction system from Charnwood with a 370mm diameter filter sock (top), the collector body (middle red box) and dust bag (bottom). If we were to just use a dust sock in the same setup as this picture we would still be only filtering at 5 micron, only the air flow rate would improve.

1 Like

Thanks Mark for
A) Your efforts on the dust extraction so far which have really gone above and beyond. Not just in building it, that’s almost the easy bit. Sourcing the parts, CAD’ing up the room and planning what’s going to go where, and any personal funds or donations, be it fixings, wood, ironmongery, filament, buying parts, etc, etc.
B) Taking the time to research dust partial sizes and for even just caring about the welfare of everyone that uses the space.
C) Writing such a thorough post on the matter.

I really hope everyone who uses Woody on a regular basis appreciates the efforts, of you and your helpers (little shout out to Jim for all the 3D printing).

So I will pledge £30 to what I think is a very worthwhile upgrade. Thank you once more Mark.

1 Like

I’ll chip in £20. But how do we give it?

1 Like

Great question. I’m not 100% sure on the answer to this myself.

I would love to see a digit option one day on the members system, but for now I’d guess and say, see if you can give it to anyone with access to the safe.

Should the pledge fall through, everyone should get their money back which means a record will need to be kept of who’s paid what. This will have to be in paper form for now, in the safe along with the cash.

Since an option on the membership system for pledges isnt available, for now don’t put or send the money anywhere.

In the past when a pledge was run for the mill, once the total hit the required amount then everyone sent the money to the board account via bank transfer, just like manually paying membership. With a reference so whoever has bank access can track/check funds.

Once the board has all the money the parts can be bought. If people take too long, like a month then either a request for others to fill the gap, or the pledge will cancel and members will be reimbursed.

At least that’s how I see it happening. Guess it depends how quickly the total is reached

A larger filter and an upgraded 2hp fan is for sale through one of our contacts, but it requires picking up from Croydon.

Would anyone be driving down that way in the coming weeks, who would have space in their vehicle to bring this back?