Thread: Love some feedback on prelim dust extraction plan

A few comments

don't want extractor outside as i) it is close to neighbours front door and rather keep noise inside as much as possible, ii) have enough room inside.

With only a 5 x 6 m shed I'd say inside shed space is premium and it's really is worth getting the DC outside if you can
Noise on the outside is a non-issue as it's easy to get the noise down to an acceptable level if you build a good enough enclosure. My neighbours pool is right up against our common fence and I managed to get the noise down to less than his pool pump at the fence line.
Best reason is all the leaking dust is outside - it's the single best thing you can do in terms of workshop DC.

i measure about 9 metre duct to ground and then say a 2-2.5 metre flexi with 5" end.

To be brutally honest even using 6" ducting and 6" flexy this is 4HP / 15" blower territory. The 2-2.5m especially of 5" flexy is going to put a major hit on your flow.

I'd avoid 5" ducting and go straight to 6". A 5" end will throttle the flow to a maximum of 760 CFM where as for 6" its more like 1250 CFM. Of course this is for short ducting runs, no flexy and no throttled machine connections. In real situations you could be down to 2/3rds those flow rates and then the 5" ducting flow just falls way under a minimum requirement.

this is the bit i really need help on. Bear in mind i am not up to building my own system yet. As i am venting outside I don't need a bag or filter.

If you have neighbours close enough to be bothered by noise, unless you have a Bill Pentz type cyclone you will absolutely need a filter.
For a conventional DC to get better flow look at pleated filters.

Don't expect to much from a downdraft table. You might want to think later about more of a booth or a least a big enough table that you can enclose the work but putting some side or curtains up around 2/3 sides. A 30m^2 Shed is not that big so a low power High volume ventilation fan that completely vents the shed of fine dust might be a simpler option.

What you haven't spoken about is opening up machine ports.
This forum seems to have convinced folks of the need for DCs capabale of moving more air and bigger ducting but it all comes to a crashing halt if the machinery ports are not opened up.
To eek that last 10% in improvement you should also be looking at Bell Mouth hoods.

Great post Elliot. You're asking a lot of the questions that have been on my mind lately. I got as far building an external enclosure for my 3hp dusty. Still need to sort out all the ducting runs inside (for now there's far too much flexy involved). So I'll be keen to hear what people say. I also have a low ceiling so, like you, want to avoid ducting runs above.

What part of Auckland are you based in? I'd be keen to come check out your setup, and you're welcome to come see what I've got going in my garage. I don't know if I'll be much help to you, but keen to find out more anyway.

Reading your reply before bed was a mistake!

Actually just lost my last long reply to a website freeze. here is a shorter version. See attached redesign of workshop.

Sanding station
2x extractor fans servicing sanding area. roll away belt sander and oscillating spindle sander under bench. Hand sanders on bench. Hopefully pick up som bandsaw mess as well. How big would you go with fans?

Dust extractor / ducting
I just cannot put DE outside unfortunately. I can vent outside no prob though. New DE location is actually far more handy centralised in WS.

1) Ideally I have a cyclone stack and then a vent outside. Bob - you mentioned still needing a filter? Not sure I understand why?

If i cannot stack it all under 2metre stud then i have 2 other options.
2) put motor/impeller next to top of cyclone and connect via curved hose (assuming I can put motor and impeller upside down??)
3) put motor/impeller on outside wall in box (not sure wife will like this). This keeps some noise outside, and creates a bit more room and straightens the connection between cyclone and impeller (see drawing)
Prefer option 1 then 2 then 3

Quite happy with new ducting option inspired by Bob. Basically a straight line primary line.
1) small offshoot at start to service BS (see drawing)
2) TS offshoot is fixed metal duct to floor with sweep on bottom. 1 metre from ground an offshoot toward the TS. 0.5 - 1.0m flexi hose from there. about 3m fixed and 0.5m flexi. a lot better than 9m
3) to P/T: straight run to 500mm out from wall and then curved down it to 1m off ground. then 1m flexi. about 6m total with only 1 gentle curve.
Note: cannot bring myself to bastardise my machines to 6" outlets sorry.
Note: will probably not use drop saw much so will just use vac on this. maybe in future i'll extend the duct from the p/T.


Hopefully that is more in line with your suggestions Bob? Punch me in the face again please.

cheers
Elliot

Hi Woody,

Yeah I am trying to scramble up the learning curve as quick as possible. My dad (who lives with us) is the keen woodworker but his current setup is so dangerous. I am keen as well and my son loves it. We started by getting him some good and safe machines - lost an arm and a leg in the process. As part of our reno we want to enlarge and future proof the workshop. I am the design committee and want to finalise as much as possible before we start building.

Unfortunately I have descended down the rabbit hole that is dust extraction (and shop layout and tools).

I'm in Parnell by the Cathedral. There isn't a lot to see unfortunately until the new machines arrive and renovations get underway ... but if you want to come and look and throw some ideas around that would be great.

Where are you based?

Cheers
Elliot

Originally Posted by ejw1234567890

Sanding station
2x extractor fans servicing sanding area. roll away belt sander and oscillating spindle sander under bench. Hand sanders on bench. Hopefully pick up som bandsaw mess as well. How big would you go with fans?

1000 CFM will vent an air bubble about 900 mm in diameter which will cater for a medium/small sanding area/volume. This has to be real CFM and you should be aware that not all manufacturers report CFM accurately. In most cases you can halve the manufacturers data for flow rates an you will be closer to reality. Extractor fans can make a lot of noise - look for squirrel cages fans which are much quieter.

I just cannot put DE outside unfortunately. I can vent outside no prob though. New DE location is actually far more handy centralised in WS.

Based on the " don't want extractor outside as i) it is close to neighbours front door and rather keep noise inside as much as possible, ii) have enough room inside." I assumed you could put the DC outside and the reason you didn't want to was just the noise factor. Enclosing the DC inside and venting outside is fine.

1) Ideally I have a cyclone stack and then a vent outside. Bob - you mentioned still needing a filter? Not sure I understand why?

You cannot use any old cyclone and hope it removes enough fine dust from the air flow.
Remember
i) Dust smaller than ~10 micron dust is invisible until it settles out.
ii) Wood dust generation is not the same across particle sizes. There is around 100 times more dust (mass) produce in the 10-1 micron range than there is in the 1-0.1 micron range .

The only cyclone I can be assured of that filters out sufficient dust in the ~10-1 micron range is the BP cyclone design. There's a reason Bill Pentz designed his cyclone with a 15" impeller and a 4HP motor and that is because;
a) pressure losses are the lowest of all cyclone designs and this leads to the highest flow rates
and
b) the bulk of the fine dust between 10 and 1 micron is removed.

Other designs might look like they are not letting much fine dust out (i.e. air looks clear) but you cannot see the ~10 to ~1 micron dust until it eventually accumulates over your neighbours yard. I would not recommend ANY sort of chip catcher or cyclone unless an overall BP approach is used. Smaller cyclones can be use to produce good filtration but the flow rates will be compromised and leave the fine dust behind in the shed
The greatest flow rates for smaller systems are still achieved using filters (preferably pleated) and with regular cleaning.

Note: cannot bring myself to bastardise my machines to 6" outlets sorry.

Well I'm sorry too, and in that case you are largely wasting your time with those machines.
Most folks put way too much effort into fiddling with DCs etc with limited or no gains in air flow, when small changes to machine ports will make a much greater difference in air flow.

None of my machines have been chopped to the point where they look bad. In many cases you don't need to bastardise anything - you might be able to remove some machine panels with 4 or 5" holes and replace them with panels that have 6" ports.

Bandsaws are just as well serviced using 3 x 4" ducts as by 1 x 6" duct but you do need to remove the grates/grilles inside the ports, and locate at least one of the extraction point directly under the table. I cut a hole in the door of my BS to add extra flow and added a grille over the hole and don't reckon it looks too bad.
WWBSdustport.jpg
It's not essential to cut a hole - some folks just arrange it so the door can be left ajar.

Sanders can have their ports removed completely and replaced by appropriately located bell mouth hoods.
BeltSanderMS.jpg

The most difficult one was the combo planer/thicknesser where I completely remade the dust pick up chute - it's also the most effective.
I can replace the old one if I need to but why would anyone want to do that is beyond me.
Transition1.jpg
I realize not everyone can do this but where there's a will there's often a way.

Dropsaw don't need anything done to them - extraction is done by building a canopy behind the saw.
Have a look around in the dust forum - some members have come up with ingenious improvements that are really worth pursuing.

Table saw are one of the most difficult. I usually recommend starting with a completely new blade guard. If you have to cut a hole in the cabinet a well made panel and port can be manufactured and painted to look the same as the original, and attached over the top of a cut hole.

Elliot you said you have room in the shed but limited by low ceilings. A cyclone can be mounted on an angle to fit under a low ceiling at the expense of wall space although you can still cram stuff above and below it so it's not completely wasted. Therefore a 2 + meter cyclone can lay over 45 degrees and fit in a 1.5 meter high space.

Bobs endorsement of the Bill Pentz should be strongly considered. I got an email from a company in the US boasting of its new cyclone that fits in low ceiling shops. It is basically a short cone & cylinder design. They claimed it separated dust down to 20 microns. Anything finer had to be filtered out. The BP cyclone if much more effective. It looks like many of the Asian made compact cyclones so that implies how good they might be.

If you are limited to a 3 hp motor (Shed power?) I believe Bill Pentz has the info on making a cyclone to fit on his site. I can't verify at the moment as I'm using the phone for this. There is/was one of your countrymen that made a fiberglass version and has the moulds for making more. Maybe search this part of the forum for fiberglass cyclone and see if the thread comes up. He might be able to make one for you.

Pete

The fibre glass cyclone by Muchacho. Fibreglass Cyclone Mark 2

Hi Bob,

oh man, this topic is tricky with a low ceiling! I am still trying to gather my thoughts but I think what you are saying is with a low ceiling I cannot make real use of a cyclone. This is because you need a certain height and HP to make cyclone systems have enough CFM at the machine head. That is, if I tried to do a cyclone system with a 2 metre high ceiling, all I am really going to achieve is better separation ... but this will be at the expense of leaving more fine dust in the air from the weaker machine draw.

Another words, I would be better off having more CFM by not going through a cyclone ... as long as I keep my filters cleanish. This leads me down the path of finding a fit for purpose model. I can see I am running into problems here as well.

Main problem if that I want a ducted system I really need +3HP. Problem with 3HP models are that they are both high (circa 2m) and wide (usually double bagged so 1.4m). More money and space taken up!

I can probably get the same or better CFM at the machine head by having a smaller 2HP right next to the TS and P/T (achievable in my plan). Hmmm, a lot less money spent, more room in shop ... for only a minor loss of convenience. I think this is where you were pointing me?

Something like this?
https://www.trademe.co.nz/business-f...1424017085.htmor something like a Felder AR-14 or AR-22?

Fan
I still like your extractor fan idea, especially as a 2HP DE will be over the other side of shop. Question i have for you is, will a good fan over here also be good at picking up and ejecting the very fine dust from the room in general, or is it really just to service the sanding area?

If the extractor fan will help pick up the really fine duct in the whole room (the dangerous stuff), then I think go the good 2HP + good extractor fan.

Note: would putting a small fan at the other end of the WS to the extractor fan help move fine dust or will a draft do it by itself? I really know nothing about movement characteristics of fine dust!

I think i found a type that you were referring too?
https://www.trademe.co.nz/business-f...1427630424.htm
Is, 5000 CM/H (which is 3,300 CFM), so might be a bit of overkill but there are models down from this. I could stomach $1,400 if I saved money elsewhere and it helped cleanse the room of nasties. Need to look into noise a bit more but if it is on intermittently during the day its not such a big deal.

Other
In case you are wondering, 5m further up (north) makes a big difference to the neighbours as its away from front door and through a lot more bush. Also, if you have a look at one of the freehand drawings, you can see that 800mm high in the WS is close to ground level outside, which mean the extractor fan will be going into a small block wall 1m away, helping to buffer the noise and dust. Their ground level is about 2m below the top of the wall as well. Plus, NZ is known for its wind!

I like the bell mouth. I'm going to do that for the belt sander ... or ditch the belt sander and go with hand held belt sander on bench by extractor fan + shop vac. Kind of hoping spiral cutter head and precision thickenessing will reduce the need for the dust belching belt sander.

I am going to attack the thicknesser at some stage. I see a few people do this and get far better results. The Hammer machines better hope they perform!

Again, thanks a lot for your help. I hope you guys realise how much you help people like me and take satisfaction from it - you deserve it all.

Cheers

Originally Posted by ejw1234567890

I can probably get the same or better CFM at the machine head by having a smaller 2HP right next to the TS and P/T (achievable in my plan). Hmmm, a lot less money spent, more room in shop ... for only a minor loss of convenience. I think this is where you were pointing me?

Nope, it doesn't matter what side of the DC the ducting is on you still have to vent the air and dust outside the shed so you are back to the same ducting length . If you plan to vent inside the shed you will still have a serious fine dust problem.

would putting a small fan at the other end of the WS to the extractor fan help move fine dust or will a draft do it by itself? I really know nothing about movement characteristics of fine dust!

the small fan won't make a lot of difference

I think i found a type that you were referring too?
https://www.trademe.co.nz/business-f...1427630424.htm
Is, 5000 CM/H (which is 3,300 CFM),

Yep that's the style/type . I get 2940 CFM from 5000CMH, and in practice you'll probably end up getting about 2000 CFM. It is a bit of overkill for a 30m^2 shed, especially give how low it is, and being 2.2kW will chew up a lot of power- shoot for something about half that and you should be able to get away with 0.5kW . Being a 2800 rpm fan means it will be noisy so make sure you hear the noise they make before you buy. Variable speed is worth considering - run it flat out while sanding and then back it off afterwards to help vent the shed. A 1440 RPM fan makes a lot less noise but needs to be bigger to move the same amount of air.

I like the bell mouth. I'm going to do that for the belt sander ... or ditch the belt sander and go with hand held belt sander on bench by extractor fan + shop vac. Kind of hoping spiral cutter head and precision thickenessing will reduce the need for the dust belching belt sander.

Shops vacs are noisy and poor for most dust control dust because most don't grab enough fine dust at the source to start with. I have a wet and dry VC that has an exhaust port that a hose can be attached to and attached to my DC but I rarely do that. I use that VC only when I am away from my shed and then I usually vent the exhaust out a window. Most VCs leak like sieves and on most of them the motor cooling loop minces coarse dust into fine dust. The best place for a VC is like a DC, outside the shed and duct a network of 50 mm ducting inside the shed. John Samuel and others have done this successfully.

Going back to ventilation fans you might want to look at a used Evaporative AC fan - they pump out lots of air and make very good ventilators. At the mens shed where I am a member the Evap AC fan does a very good job of getting rid of fine dust that escapes from machines that haven't yet been been attached to or optimised for dust collection .

Bob may be able to confirm, but I'm not sure a squirrel cage fan would be suitable to move chips as well as dust.
This is a front view of the fan in the link you posted.

IMG_0902.JPG

Originally Posted by Lappa

Bob may be able to confirm, but I'm not sure a squirrel cage fan would be suitable to move chips as well as dust.

That's correct but I don't think he intends on using these for chip collection - just ventilation.

Your right! That's what happens when I try to read the forum from a phone screen

Originally Posted by ejw1234567890

Hi Woody,

Yeah I am trying to scramble up the learning curve as quick as possible. My dad (who lives with us) is the keen woodworker but his current setup is so dangerous. I am keen as well and my son loves it. We started by getting him some good and safe machines - lost an arm and a leg in the process. As part of our reno we want to enlarge and future proof the workshop. I am the design committee and want to finalise as much as possible before we start building.

Unfortunately I have descended down the rabbit hole that is dust extraction (and shop layout and tools).

I'm in Parnell by the Cathedral. There isn't a lot to see unfortunately until the new machines arrive and renovations get underway ... but if you want to come and look and throw some ideas around that would be great.

Where are you based?

Cheers
Elliot

Great. I'm based out in Cockle Bay but work in the city. I'll PM you.

Originally Posted by BobL

Nope, it doesn't matter what side of the DC the ducting is on you still have to vent the air and dust outside the shed so you are back to the same ducting length . If you plan to vent inside the shed you will still have a serious fine dust problem.

the small fan won't make a lot of difference



Yep that's the style/type . I get 2940 CFM from 5000CMH, and in practice you'll probably end up getting about 2000 CFM. It is a bit of overkill for a 30m^2 shed, especially give how low it is, and being 2.2kW will chew up a lot of power- shoot for something about half that and you should be able to get away with 0.5kW . Being a 2800 rpm fan means it will be noisy so make sure you hear the noise they make before you buy. Variable speed is worth considering - run it flat out while sanding and then back it off afterwards to help vent the shed. A 1440 RPM fan makes a lot less noise but needs to be bigger to move the same amount of air.



Shops vacs are noisy and poor for most dust control dust because most don't grab enough fine dust at the source to start with. I have a wet and dry VC that has an exhaust port that a hose can be attached to and attached to my DC but I rarely do that. I use that VC only when I am away from my shed and then I usually vent the exhaust out a window. Most VCs leak like sieves and on most of them the motor cooling loop minces coarse dust into fine dust. The best place for a VC is like a DC, outside the shed and duct a network of 50 mm ducting inside the shed. John Samuel and others have done this successfully.

Going back to ventilation fans you might want to look at a used Evaporative AC fan - they pump out lots of air and make very good ventilators. At the mens shed where I am a member the Evap AC fan does a very good job of getting rid of fine dust that escapes from machines that haven't yet been been attached to or optimised for dust collection .

Thanks for this. I am totally rethinking my plans now. will be back!