Thread: Dust Extraction-Venting Outside: To Suck or Blow??

The fine dust will work its way back into your shed.

Blowing is a complete waste of time. What you are doing is blowing out the big stuff and just re-suspending all the fine stuff inside the shed (you cannot blow that stuff outside because you can't see it). The big stuff just takes up space and looks ugly but its the fine stuff that causes the health problems.

I'm sorry to say this (I know I sound like a broken record) but for both noise and dust minimization the best way is to put the whole DC outside. Unless you are talking about runs of 10 or more metres, or something like a big thicknesser (which one tries to locate as close as possible to the DC) a basic DC can handle runs of a few metres quite easily.

point taken.
Being at the top of a hill in a rural area, I was hoping that this would be minimal. Maybe I could install the standard filter bags outside. The other option of course is to install the very expensive real filters (pleated cartridge) in the shed. I dont have a feel however for how long these last.

thanks Bob.
I'll look have another think about rearranging the toys to make it to an external wall.

Originally Posted by Brett_wood

point taken.
Being at the top of a hill in a rural area, I was hoping that this would be minimal. Maybe I could install the standard filter bags outside. The other option of course is to install the very expensive real filters (pleated cartridge) in the shed. I dont have a feel however for how long these last.

Wow - rural area - nice, surely you must have heaps of room outside?
I'm the opposite, inner city 1/8th acre block - edge of block within 750 mm of the house on one side and 1.25m on the other. If you don't want to instal a ducted system but still have the opportunity to put the bags outside I would definitely do that

I made a small lean-to just big enough to keep the rain off the machine outside at the back of my shed and put a standard 1HP DC in there. Nobody's going to mess with it as it's over run with bouganvillia and I keep it pruned just enough to empty the bags. I run it as soon as I start making dust, or weld, or painting or anything else involving odors. Dust, fumes and solvents all go out the back and are replaced by fresher air coming in the front door.

I have a ducted system inside to 4 machines (TS, Lathe, DP and a baby [4"] jointer) plus 2 x 3 m flexible hoses, one in the middle and another at the side of the shed, that I can swing into action in a variety of ways, eg as an overhead dust collector on the TS guard, collect dust from a router, belt sander, or use as a vacuum cleaner, or ocky strap to the front of the lathe to help catch those bits that flick towards the front, or just lay on the work bench when I'm hand sanding or planing and tip the shavings that build up in the plane towards the open hose. Being only 1 HP my system is a bit stretched - I have a 2 HP unit in a box ready to replace it as soon as I'm up for it.

I don't think those pleated filters are as good as they sound but if you have to locate the DC inside they are better than nothing. The killer dust is the stuff that's around one micron or smaller - and although the total volume of the sub-1 micron particles in the average shed is very small (probably less than a peppercorn) the total number of particles is huge. The only known way to collect this fine dust is using HEPA filter technology - the alternative is to expel it outside where is is diluted in the atmosphere - the total amount it adds to the atmosphere is very small - a bit like peeing in the ocean.

FWIW I have 20 years experience building dust free clean laboratories and have measured dust profiles inside and outside buildings using laser based particle monitoring systems.

Pleated paper filter cartridges would prob be your easiest but most expensive solution.

I've not read anywhere that they don't last.

Another option (for cheapskates like me) was an Xpelair fan from a building demolition place attached to a couple of metres of flexduct positioned behind the lathe. (Yeah, just the one machine at that stage). That picked up much of the fine sanding dust.

But not enough so I then added a box-type filter.

Neither of these did much for shavings of course so in the end I installed a DC with pleated filter and removed the Xpelair set up.

I was a bit disheartened when I started playing more seriously in the shed with a 2hp ducted system.
I put the DE outside (in a carport attached to the shed (for noise reasons only, didn't know that "bad" dust was coming out of my bag filters)) and connected it all with 150 and 90mm ducting. I just expected everything to be sucked up the pipe and dissapear. If my DE sucks at one end of a duct, surely the same amount of air must come in the other end?
I didn't give any of this much thought (didn't realise I had to).

The runs were long: so they pick up everything and hugged the tall ceiling height to keep everything neat. My attachments were 90 degrees (using standard PVC fittings). And I joined onto the standard air extraction points on my tools (thinking that going from 150mm to 90mm to something small would just increase the velocity of the air (hence making it work better)).

Unfortunately, it would seem as though all of this was wrong on so many levels after reading up on cyclones and the like. It would seem as though I need to rethink and maybe start from the tools instead of the DE end in the extraction system design.

Originally Posted by rsser

Pleated paper filter cartridges would prob be your easiest but most expensive solution.

Another option (for cheapskates like me) was an Xpelair fan from a building demolition place attached to a couple of metres of flexduct positioned behind the lathe. (Yeah, just the one machine at that stage). That picked up much of the fine sanding dust.

I've found that too.
When wood dust was just something that got in the way and covered my safety glasses, nothing worked better when turning than a big ass fan blowing at the workpiece.

Yeah; the Xpelair sucked rather than blew though so the dust was removed from the shed.

I have a 4 hp De and I have installed it outside the shed in a sound proof enclosure (many dollars) I have also installed pleated filters to keep the yard clean and the neighbours happy. I have a 200mm main runnig the the length of the shed and run 100mm from that to my machines etc. My shed has mutch less constant backround noise with the de outside