|LaymarCrafts Woodturning||Hints & Tips|
|Dust Control in the Workshop Pt. II|
In the first part of this Article I described my solution for extracting Dust and Shavings at the Lathe but this did not cater for the extraneous Dust that escaped capture or is generated by other Machines.
The simplest form, but least efficient overall, is a Extractor Fan removing a reasonable amount of Air out of the Workshop to the Outside, this has some drawbacks the two most critical are that it will remove any Heat that you are generating for keeping Warm on Cold Days and the Dust will settle around the area adjacent to the Fan.
Having decided to proceed I first obtained a suitable Fan and Motor based on exchanging the Air in the Workshop 10 to 15 times an hour as this seemed a reasonable amount for what I was wanting to achieve and corresponded with some Ventilation Guidelines for Dusty Environments.
To calculate this I first measured the internal volume of the Workshop (L x B x H) and multiplied this by 0.75 on the basis that at least 25% of the volume is taken up with Machinery and Wood, this came to 16m³ (565ft³) and therefore I would require a Fan rated at 160 to 240m³/hr (approx. 5,700/8500ft³/hr) if I was to achieve the required Ventilation Rate.
The Fan I obtained was from an old Air-conditioning Unit, which was rated at 255m³/hr and all that I needed to do was mount it into a suitable Fan plate with a Hole equal to the Fan Diameter + 25mm [1"] to accommodate the Impellor (Fan Blade).
The basic layout is shown below I first cut a suitable square hole in the Wall of the Workshop to take a short length of Ducting which I fabricated from 3/8" Plywood, this requires to be at least as long as the total Fan Assembly plus 25/50mm (1"/2") for clearance.
Into this Duct I then fitted the Fan Plate, again cut from 3/8" Ply with a Hole cut in the middle equal to the Diameter of the Fan Blade + 12mm (1/2") for Tip Clearance.
Into this you now have to fit the Fan and it's Motor and depending on the Motor mounting this will either have to be some form of Bracket or a Beam, whatever method you use it will need to be strong enough to ensure the Fan Blade does not hit the Fan Plate when the unit runs.
I fitted simple 1/2" square Wire Mesh Front and Rear as a Protective Guard to ensure that Fingers or any large objects could not come into contact with the Fan and cause damage.
Now that this was fitted and wired up to a suitable On/Off Switch I was left with a situation where the Dust being ejected from the Fan would spread itself over my neighbors Garden and beyond.
The Wall I had chosen to fit the Fan into was in fact 1m (3ft) from the Fence surrounding our property and this situation presented me with an opportunity to add an additional facility, an Air Drying Wood Store to the side of the Workshop using the Extracted Air and at the same time containing the Dust and directing it away from my neighbors property.
The construction was kept as simple as possible as I only had access from one side so I decided to use three sheets of Corrugated Tin, one to form the Back and two for the Wall leaving the Front open for Access.
The Fourth Wall of course being the Workshop Wall with the Fan in it.
The Roof was also from the same Corrugated Tin with a slight slope for drainage.
For the Door I used Heavy Duty Plastic Sheeting as this gave me easy access and also allowed the Air passing thorough the Wood Stack to escape and circulate.
I have found this to be more than satisfactory with very little Dust escaping and the Store is also 100% Weatherproof.
However I did have to fix the Plastic Curtain at the bottom as it had a habit of Blowing around when the Fan was on.
A word of WARNING the Store as described of course now becomes a Dust Trap and as is well known Dust can be a Fire Hazard, and this was one reason I used the Tin for Construction, as an additional precaution I empty the Store at least twice a year and vacuum up all residue Dust from the Wood and the Store.
This set up has been in use for nearly 3 years and to date I have had no mishaps but I am not 100% in control of the situation and you have to ensure that adequate precautions are taken to minimise any risk.
General Layout of Workshop [Plan] and Dust Extraction System & below the actual Fan in position [and dirty]
The plan of the Workshop above shows the relative position of the Machines in general use in the Woodturning Area of the Workshop, the Extractor Fan Unit draws the Air across the Lathe via the Doorway into the Workshop and therefore always induces clean fresh Air into the area where I would normally stand when Turning.
Likewise if I am using the Mini-Sander, the Grinder is in the position shown for convenience but could be a Fire Risk if any Sparks are sucked in by the Fan I have therefore Electrically Interlocked the Grinder and the Fan, now any time I switch the Grinder on the Fan is automatically switched off and the danger from Sparks is removed.
The effectiveness of the Store in Drying Wood appears to be quite good, I generally use it for Green Logs of 2"/3" Ø which I convert into Fungi or Weed Pots and these are ready for use within a Year which has halved the time from when I just stacked the Logs under a Tarpaulin.
Part I of this Article on Dust Extractor System.
Article on Dust and the Lathe.
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Last update 19 July 2007
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