Quite some time ago, I was fixing a Dyson vacuum cleaner and finally got to have a close look at how the tiny centrifugal dust collectors work.
I find the entire concept rather cool.
Spin the hell out of the airflow and the crap in it separates, then falls away on inner surface of the wall.
It's just like the gravitron for dust particles. What really impressed me was how fine the collected dust was.
It was finer than the dust that adheres to your fingerprints on the windows of your car.
If you look at properly designed bagless vacuum cleaners, they'll often have a similar type of mechanism that collects fine dust via a centrifugal mechanism. I initially thought mine was just a aesthetic design feature, but then noticed that fine dust built up there regularly.
Anyway, quite a few clubs have arrow saws. I've noted that ours gets more use than I thought it would. I've also noted the build up of carbon dust around the area which concerns me a little bit. Carbon dust isn't your friend.
Since upgrading our arrow saw, the vacuum which is supposed to be used with it isn't regularly used. I had plans to make the bench into a vacuum table by drilling holes in it and pulling air through with the vacuum, but it's not going to work because of the saw base plate being pretty solid.
I'll have to make some sort of ducting.
The real issue is the carbon dust. It's fine stuff and eventually clogs all sorts of filters. If the filters aren't fine enough, it goes through some vacuum cleaner motors. Conductive dust is generally bad news.
I've been keeping my eyes out for dust extractor separators and a couple of weeks ago, some reasonable sized ones turned up on ebay.
<$18, including delivery? I'll have a play at that price.
They turned up today (I bought two, expecting this to work)
I went to Bunnings and walked around looking for ideas for a container. Originally, I thought a 20 liter bucket would do the job and it would have, but the lids that were available were pretty rubbish, so I went to plan B which was a meter of 150mm PVC pipe and two end caps.
I put one cap on the pipe in the shop and then tried to cap the other end. It actually didn't want to seat as the seal compressed the air inside. The top kept popping off.
This is a good thing. I can be super lazy.
I grabbed a rubber 50mm adapter and some 30 mm step down fittings as well as I don't have enough large diameter vacuum hose to link everything up.
Once home, I cut the 150mm pipe in half and just pushed a cap on one end, then drilled the holes to screw the separator to the middle of the other cap. The hole in the middle is 60mm to let the dust fall into the pipe container. My guesses were good for the pipe adaptors and some sticky tape provided the minimal sealing to hold the small hose on.
With the big hose perfectly joined with the rubber 50mm to 50mm adaptor, I decided it was time to test this. I have to admit that the reduction in diameter isn't optimum. I would be losing a reasonable amount of flow.
Providing the suck is my trusty and much abused Shop Vac Pro 20.
After vacuuming the gaps in the floor boards, I decided that this was totally pointless and went looking for some suitable dust. In the end, I discovered that there was some corn flour left over from carp bait experiments and just tipped it all over the floor. There was a good amount of it. Easily half a litre spread over a square metre or so.
I figured that white would be easy to see, so vacuumed it up slowly.
It turned the filter into a huge static generator. I've never experienced better.
When it was all finished, I popped the lid on the PVC pipe and found what looked like all of the flour in there. Then I popped the lid of the shop vac to see how much made it inside.
That's when I discovered that it was reasonably full. Apparently I've vacuumed the floor some time in the last year. However, there was no find white dust coating which I expected.
So I went out and emptied the vacuum and cleaned the filter roughly, then dumped all the flour out and did it again.
To my absolute amazement, there was not a single trace of the flour making it to the shop vac compartment. I would have thought that SOME would have. I actually still can't believe it.
I have no idea how long it would take to fill 8.8 litres with carbon dust from an arrow saw, but I can say that I wouldn't expect to be checking it more than once a decade.
If anyone else is a little bit concerned about containing their arrow saw dust and is using a vacuum cleaner for it, something like this will keep the filter from progressively getting worse.