I needed a dust extract for my bandsaw.
My old extract was one of those with a polythene bag and a bag filter on top. It used to fill the workshop with the finest dust that got through the filter.
So I cadged an empty oil drum off the local garage, as the basis for a cyclone. Step aside Mr Dyson.
The old 1/2 hp blower of the fiter was repositioned with some ductwork from the bandsaw and straight out through the wall.
The idea was to squirt the output round the drum, where it would accelerate as it worked its way to the centre, and out of the pipe in the top. The heavier dust wouldn't be able to make its way in to the output pipe and would fall to the bottom of the drum. Simples. Here's mark 1.
It didn't work. Some of the largest lumps accumulated in the bottom of the drum, but lots of fine dust came out of the top and covered the garden. Added to that the pressure inside lifted the lid until dust came out of the join. When I took the lid off it was obvious that the air inside had been turbulent, and not spinning cleanly.
Mark 2 had the top edge cut off the drum, and left over pop top seal was added to make an airtight join with the lid. I put three bolts through the side of the drum just below the inlet pipe, and put a circular chipboard shelf with a half inch gap round the edge to try and keep the air rotating cleanly, then the dust could fall through the gap.
Then to stop the lid lifting I added some hold down bolts, and a cover to stop rain blowing in through the pipe at the top.
It worked!
Now I could hear the air rotating very fast at it came out of the top. I've been using it now for the best part of a year, and it collects almost 100% of the dust, some of which is very fine. I take all my wood chip and dust to a guy who makes fuel briquettes, in exchange for the odd item from his architectural salvage business.
My old extract was one of those with a polythene bag and a bag filter on top. It used to fill the workshop with the finest dust that got through the filter.
So I cadged an empty oil drum off the local garage, as the basis for a cyclone. Step aside Mr Dyson.
The old 1/2 hp blower of the fiter was repositioned with some ductwork from the bandsaw and straight out through the wall.
The idea was to squirt the output round the drum, where it would accelerate as it worked its way to the centre, and out of the pipe in the top. The heavier dust wouldn't be able to make its way in to the output pipe and would fall to the bottom of the drum. Simples. Here's mark 1.
It didn't work. Some of the largest lumps accumulated in the bottom of the drum, but lots of fine dust came out of the top and covered the garden. Added to that the pressure inside lifted the lid until dust came out of the join. When I took the lid off it was obvious that the air inside had been turbulent, and not spinning cleanly.
Mark 2 had the top edge cut off the drum, and left over pop top seal was added to make an airtight join with the lid. I put three bolts through the side of the drum just below the inlet pipe, and put a circular chipboard shelf with a half inch gap round the edge to try and keep the air rotating cleanly, then the dust could fall through the gap.
Then to stop the lid lifting I added some hold down bolts, and a cover to stop rain blowing in through the pipe at the top.
It worked!
Now I could hear the air rotating very fast at it came out of the top. I've been using it now for the best part of a year, and it collects almost 100% of the dust, some of which is very fine. I take all my wood chip and dust to a guy who makes fuel briquettes, in exchange for the odd item from his architectural salvage business.
