Thread: How do you empty your dust extractor

As it is outside or not in your workspace, I don't understand why spilling a bit of dust is a problem?

Put a cyclone between the tool and the dusty and you will never have to empty the dusty again. problem solved!

I recently acquired a 2hp dusty secondhand and it was half full when I got it so I know what you are talking about with the problems. I was running a 1hp dusty to power teh cyclone and just used the 2hp as an upgrade. I agree there is no point in collecting all that dust just to let it out again in the shed.

For anyone who has the means to do so, I would highly recommend a cyclone collector and the dusty vented outside the shed. I made my cyclone collector myself, with a littel help from a sheet-metalworker friend, out of two 44 gallon drums. It works great.

Doug

Originally Posted by BobL

As it is outside or not in your workspace, I don't understand why spilling a bit of dust is a problem?

Some confusion exists - its inside, not outside.

cheers
Arron

Before I empty my dusty, I make sure I rotate the paddle on my pleated filter vigorously and then let the dust settle internally, usuaaly a couple of hours, before I attempt to remove the bag. This action also tends to remove the dust from the internal sloping area.

I guess my system is much the same as yours. Fixed inside and in a cabinet, pleated filters atop and plastic bags under. The day before I'm due for an empty, I give the filters a good spin and knock to drop the dust and give the dusty some little sharp rocks back and for to precipitate as much dust as possible into the bags. Next day, armed with Trend Airshield and Nilfisk dust extractor I remove the bags (I only let them get to about 1/2 full which helps stop puffing out dust when you fold the tops over) and install empty bags. I then do a clean up of any chips/dust that fell into the cabinet with the Nilfisk. If it's a breezy day I have the workshop open to encourage any dust to leave, otherwise I run the dusty for a while.

Originally Posted by Big Shed

Before I empty my dusty, I make sure I rotate the paddle on my pleated filter vigorously and then let the dust settle internally, usuaaly a couple of hours, before I attempt to remove the bag. This action also tends to remove the dust from the internal sloping area.

I also rock mine around a bit and this seems to move most of the dust on the slope.

Originally Posted by doug3030

For anyone who has the means to do so, I would highly recommend a cyclone collector and the dusty vented outside the shed. I made my cyclone collector myself, with a littel help from a sheet-metalworker friend, out of two 44 gallon drums. It works great.

Before doing this everyone should consider the effect on invisible dust.
Inserting even a very efficient cyclone anywhere in the path of the DC reduces the flow rate of the DC.
This means
1) it reduces the collection of invisibles at source. Allowing them to escape into the shed.
and
b) This slows down the subsequent scrubbing time to remove the escaped invisibles from the shed

If the DC is a 4HP or larger unit (with matched impeller ) then flow rates are usually enough to grab fine dust to begin with then so it is not as critical if a cyclone is used. This is why BP recommends using a higher powered motor and matched impeller.

If the DC is a 3HP or less (with smaller matched impeller) then the the flow rates generated by these units are already borderline or even sub-borderline at collecting invisibles at source so adding anything in the way between the source and the exit point of the dust further reduces flow rate. If the cyclone is not properly designed or too small then it can reduce the flow rate by as much as 40 - 50 % on a small system.

The downside is the bags/filters do need to be cleaned regularly. The 10 minute exposure you get in cleaning the bags even every few days is minor compared to the hours of greater exposure to invisibles resulting from reduced air flow. If you are worried about the risk while cleaning bags a mask can be worn.

Instead of just looking at the visible sawdust being collected by a DC and then inserting a chip catcher into the DC path and saying "Yep - still works good" I encourage users to construct a U-Tube manometer (pressure gauge) and check the pressure difference with and without the catcher.

Sometimes small modifications can be made to chip catchers which improve their flow rates, but without an air flow meter or a pressure gauge it is impossible to tell if the flow rates have been improved.

Originally Posted by doug3030

Put a cyclone between the tool and the dusty and you will never have to empty the dusty again. problem solved!

I recently acquired a 2hp dusty secondhand and it was half full when I got it so I know what you are talking about with the problems. I was running a 1hp dusty to power teh cyclone and just used the 2hp as an upgrade. I agree there is no point in collecting all that dust just to let it out again in the shed.

For anyone who has the means to do so, I would highly recommend a cyclone collector and the dusty vented outside the shed. I made my cyclone collector myself, with a littel help from a sheet-metalworker friend, out of two 44 gallon drums. It works great.

Doug

Doug, I thought about putting a cyclone, or even just a separator, before the dc, but I read here that most diy cyclones and/or separators tend to drop the airflow quite a bit - so while the solving the large dust problem they reduce the dcs ability to extract the micro-dust. This is made worse for me having only a 2hp dusty.

Though I'm not currently dealing with micro-dust, thats where I"m heading.

cheers
Arron


edited : looks like both Bob and I posted at the same time ...

Originally Posted by Arron

Some confusion exists - its inside, not outside.

cheers
Arron

OK.
Sorry if I sound flippant, but if it's inside then it doesn't matter either. Your shed is already essentially saturated with invisible dust so adding a little more doesn't really matter.

Originally Posted by BobL

OK.
Sorry if I sound flippant, but if it's inside then it doesn't matter either. Your shed is already essentially saturated with invisible dust so adding a little more doesn't really matter.

Actually, its saturated with visible dust as well

Seriously, being able to deal with the invisibles is where I"m heading - but its a multi-phase project and I need to get a lot of things right first. First thing I need to do is quieten the dc - thats for the sake of the neighbours. Once I've learnt how to do that, I can go to a larger dc and vent outside. Currently, I dont even run the dc all time, so even the visible dust is not all being collected. I just wear a respirator all the time, which is irritating.

cheers
Arron

Originally Posted by Arron

I just wear a respirator all the time, which is irritating.

Yep - been there and done that.

Have you at least got some cross ventilation? From what I see of many sheds that is one of the biggest problems. the door and window are often on the same wall. In this case it is worth considering something like a whirly bird or inserting a vent in the wall opposite the biggest opening.

Originally Posted by Arron

Doug, I thought about putting a cyclone, or even just a separator, before the dc, but I read here that most diy cyclones and/or separators tend to drop the airflow quite a bit - so while the solving the large dust problem they reduce the dcs ability to extract the micro-dust. This is made worse for me having only a 2hp dusty.

Though I'm not currently dealing with micro-dust, thats where I"m heading.

Be that as it may, Aarron, I was answering your original question which was about how to avoid exposure to dust when cleaning/emptying the bag. Since our resident experts will quickly assure us, you wont get the invisible dust with a 2hp dusty, so in absence of any information on your desire to somehow remove the invisible dust with your 2hp machine, I provided you a workable solution to the problem you posed. I am aware of the limitations of my system and I have a number of other measures that I employ in my garage to help deal with the invisible dust.

I dont know why some people cannot accept that not everyone has a suitable facility to install an ideal system that will collect all the invisible dust. It does not matter what the thread starts out with, in the dust collection forum. within the first three posts it is hijacked by the "invisible dust" Nazis who then successfully stifle any meaningful debate amongs those who are trying to to reach a workable compromise to suit them somewhere between nothing and a 50hp three phase dust extractor with a matched impeller pulling through one metre sewage pipes and vented through a zero micron filter outside the shed half a kilometer away.

Hi doug,
Talk about mixed feelings, I don't know whether to say "Hear hear" to your post or say at least they let us know what we should be aiming for, so I've said both.
Of-course we stand as much chance of achieving it as a celluloid dog has of catching an asbestos cat in Hell.
Regards

Hi A Duke,

Dont get me wrong, I do appreciate their knowledge and expertise on the forum. It is just the way they go about it. You say you have a 2hp dusty (which may be all the power you can spare in your shed after running the tablesaw and the compressor or whatever so you cant go to 3hp) and the debate about how to get the best you can out of what you can use gets swalowed up in the "but you wont get the invisible dust" posts!

It would be more beneficial to everyone if they could use their knowledge to help us get the most out of the gear we can run in an Amateur garage as opposed to a puropse-built professional shop instead of telling us that we need to do what we cannot do.

Knowledge is a great thing and I appreciate the depth of knowledge that members of this forum freely give to other members over a great range of topics, not just dust collection. but too often they complicate the issue and provide great solutions to problems way beyond the original poster's inquiry. If someone asked them the time they would probably give them instructions to make a grandfather clock.

Doug