Rigid ducted dust extraction - any hints and tips?

[Wouldchuk]

Hello folks,

Some advice please regarding a dust collection system for those of you with the luxury of larger workshops or those using a permanent installed ducting system.

I have to resolve dust and shavings collection as my mobile collector is often buried in stuff and for those quick but dirty jobs, it is all too easy to say “sod it” and just get on without using it. It’s also never quite in the right place, with the right hoses. This isn’t ideal so I want a more permanently installed option, using a wall-mounted rigid duct system, with gates to open different suction ports for different machines, with appropriate flexi-ducting attached at those ports/machines accordingly.

I was also thinking that there is no reason why I have to lose workshop space inside when I have plenty of room OUTUSIDE – I could very easily build a small ‘extension’ out the back of the workshop in which I permanently mount my dust and chippings extractor, with the control inside. What I lose in terms of having to nip out and round the side of the workshop to empty it, I gain in the floorspace and working area gained. There may also be benefits in that all that fine dust potentially being expelled by the extractor is all going outside.

I have a broadly rectangular workshop which is around 4m along the back wall, where things like my bandsaw, router table, table saw, planer are stored – these tend to be wheeled forward into the central area for working space, then pushed back again when finished.

I am thinking of running a 4m length of rigid ducting along that wall – with perhaps four ducts for the big machines as described, then perhaps a couple of smaller ports to allow for a more flexible approach, with a stopped end. I’d only be using one at a time, and as I swap between machines i can just shut the blast gates. Initially, I will probably just use the extractor inside, attached to the end of that 4m length, first to test it – and then when time allows and if I am happy with the system I may cut a hole through the wall and put the extractor on the outside as described.


Couple of questions:

1) Do I need a certain size of extractor to ‘suck’ that length of ducting effectively? Is there any loss of suction as a result of a longer run of ducting/hose? I think my extractor is similar to a bog-standard .75kw Axminster Hobby Series model – is that ever going to be man enough?
2) Is it possible to convert this extractor into a cyclone – would that improve its efficiency at all?
3) Can you get blast gates that operate at 90degrees to the main line? The ones on Rutlands seem to just be inline – I could put a T-piece into the main duct and then the blast gate, and then the flexi-hose I guess....


Any other tips and advice much appreciated.

 

[DiscoStu]

Not sure I can help much but I have a large single garage with a tank saw, bandsaw, CSMS, a small planner thicknesser, belt sander, router table etc.

I have a Karcher wet and dry vac with a dusty deputy cyclone and this all goes to my dust centre which is basically a load of T joints with blast gates on them.

I then have hoses going to each tool and have the blast gates labeled. I just lift up the appropriate blast gate for the tool I want to use.

I also have the Karcher attached to a master / slave socket (used for turning off DVD boxed etc when you turn the TV off) I use it so that when a power tool is switched on it automatically turns of the Karcher. Therefore all I do is open the blast gate for the tool I'm using and then the dust extraction is automated from that point on. I'm only doing 2 1/2 extraction but it works really well.

I've recently moved to a remote on off switch rather than the master slave option as I am using a long Festool hose for my track saw and domino and for general cleaning up. However I may put a light into the power and have that operated by remote so I can have the best of both, if that makes any sense.

I'm sure it depends on what you're doing but for me it works really well.

 

[DiscoStu]

Here are some more photos of my set up.

 

[DiscoStu]

And from the photo it looks like I have a Dust Mite not dust deputy!

 

[Alexam]

That looks like a wonderful setup that has given me ideas. Thanks for sharing it, as I have problems with dust that need to be attended to. Do you also have a room extractor for the fine dust that may get into the air of the shop, as this is a major concern as I am asthmatic and stupidly dont aways put on my mask? I would really like to make the area completly dust free if possible.

 

[mseries]

Discostu, what capacity is your blue barrel ? What's the power of your Karcher ? how long are your tubes ? I presume shorter tubes are better ?

 

[custard]

I have a Karcher wet and dry vac with a dusty deputy cyclone and this all goes to my dust centre which is basically a load of T joints with blast gates on them.

I then have hoses going to each tool and have the blast gates labeled. I just lift up the appropriate blast gate for the tool I want to use.

Very neat, very organised, I'm impressed!

 

[PAC1]

In answer to your points:
1. In short yes. If you have a reasonable sized table saw or P/T then you probably need 750cf/m at the point of extraction. working back the more bends and different legs you have the more suck you loose but even with a straight run you can say goodbye to 25 to 30% along the length of the pipe. If you then factor in that the manufacturer's stated figures are optimistic before you attach a 1mu filter you can end up with 50% of the manufacturer's stated cf/m. Bends are killers so as straight as possible but if there has to be a bend as gentle as possible. I had a 90degree bend made to be 4x the diameter of the pipe it works well. Flexi pipe creates turbulence so keep this as short as possible. Also low pressure systems cannot compress the air so if you have a system designed to move 1000cf/m through 6 inch diameter pipe it will only move about 40% of that volume down a 4 inch diameter pipe. The reality is that you will probably find that unless you spend a fortune on the extractor the only way to shift the volume of air is to use 6 inch diameter pipe. The benefit of putting the extractor outside is you can have a less efficient filter and thus a higher volume of suck. It is also a much cleaner environment as all the fine dust goes outside rather than recycled for you to breath. The downside is if you heat your workshop it will be wasted. I put my extraction outside this year - what an improvement in air quality (I am yet to see a winter with it!) If you are going to build a outside shed think about ceiling mounting the extractor fan it will remove at least two bends.
2. Yes plenty do. you lose cf/m because the cyclone creates turbulence but gain because all the dust and chipping are separated well before they get to clog your filter so it is a trade off.
3. Avoid because fast 90 degree bends are too sharp and you lose too much cf/m. A Y piece is better than a T
I know I keep saying this on this forum but read Bill Penz website all the above came from me reading his site and thinking about the solution for me.

 

[sploo]

+1 for PAC1's comments and recommendation for Bill Pentz's site.

You can add a cyclone to an existing extractor (as a push or pull), but it's generally recommended that you have a minimum of 3hp due to the looses the cyclone causes.

This was my solution to an extraction system (written around 10 years ago): http://spikyfish.com/DustExtraction/

The filter-less outside "shed" does puff a bit of dust and I'd really like to add a cyclone or Thien separator to remove visible dust from the exhaust. Ideally I'd put the whole motor+impeller and cyclone outside but it's always proved logistically difficult (and I'd need a lot of sound insulation, and motor cooling would be an issue).

I've never tested the airflow on my system - though it can easily steal a 1" cube of hardwood off a table surface (though not lift it vertically). Because of the difficulties of trapping/capturing all the dust with most tools I do use a Trend AirShield Pro.

 

[DiscoStu]

Discostu, what capacity is your blue barrel ? What's the power of your Karcher ? how long are your tubes ? I presume shorter tubes are better ?

I'm not sure I'm going to be much help here as I wasn't that scientific about the whole thing.

The barrel is probably about 40 litres

Tubes to blast gates are around 2.5metres. Then there is obviously the tubes to the machines. The table saw is probably a 4m tube and I have a long 5m? Festool hose that gets plugged in.

I think you will loose some suction over distance but to be honest I've not noticed it. I'm not sure what power my Karcher is, it was £50 and I didn't really buy it for this use originally. I think the cyclone makes a big difference as the filter doesn't get clogged.

I did have to make a couple of MDF rings to fit the vac to the cyclone and cyclone to the tubes.

I am now planning on adding a long run of tubing from where the current set up is to the other side of the garage where I've got a lathe set up. I've got an idea to make a big funnel type affair under the lathe to capture and channel as much of the waste from that and have it go into my bin. No idea if it will work!

I don't currently have an air filter but it is next on my list. I'm currently in good health and want to stay that way!

 

[sploo]

Tubes to blast gates are around 2.5metres. Then there is obviously the tubes to the machines. The table saw is probably a 4m tube and I have a long 5m? Festool hose that gets plugged in.

I think you will loose some suction over distance but to be honest I've not noticed it. I'm not sure what power my Karcher is, it was £50 and I didn't really buy it for this use originally. I think the cyclone makes a big difference as the filter doesn't get clogged.

...

I am now planning on adding a long run of tubing from where the current set up is to the other side of the garage where I've got a lathe set up. I've got an idea to make a big funnel type affair under the lathe to capture and channel as much of the waste from that and have it go into my bin. No idea if it will work!

For an impeller based extractor (high volume, low pressure) it's very easy to kill your airflow with restrictions. When I first built my ducting I compared the "pull" from a short length of 4" hose at the end of approx 7m of the ducting vs approx 7m of the flexible 4" hose - the difference was huge. It does strike me that 4 and 5m lengths of tube aren't ideal, but with a vac you've got much higher pressure, so maybe less of an issue.

For a funnel you'd need huge air flow (volume) to pull in dust, though if it was underneath the lathe you'd have a good chance of catching a lot of material.

 

[Wouldchuk]

Thanks for the contributions - and some useful pictures and food for thought as always. That's a neat and tidy setup.

I've read reviews of blast gates that state they need to be orientated in the right way - opening upwards - so as to work best and not fill with dust. I take it that this means as per DiscoStu's setup.

I need to do some more reading on this one - any other piccies of people's set ups would be hugely appreciated as inspiration!

 

[DiscoStu]

"For a funnel you'd need huge air flow (volume) to pull in dust, though if it was underneath the lathe you'd have a good chance of catching a lot of material."

I know my Vac won't be as good as a HVLP type system for the lathe, but my theory was / is, that if if can capture most of the waste using gravity then "funnel" that to a hose out let then it should collect most of the waste, I know it won't be good for dust but most of the dust occurs at the sanding stage and I might have to create some clamp to allow a hose to be placed right near the work.

 

[PAC1]

"For a funnel you'd need huge air flow (volume) to pull in dust, though if it was underneath the lathe you'd have a good chance of catching a lot of material."

I know my Vac won't be as good as a HVLP type system for the lathe, but my theory was / is, that if if can capture most of the waste using gravity then "funnel" that to a hose out let then it should collect most of the waste, I know it won't be good for dust but most of the dust occurs at the sanding stage and I might have to create some clamp to allow a hose to be placed right near the work.

Axminster and others sell a universal clamp that you use with a jubilee clip for this.

 

[sploo]

I know my Vac won't be as good as a HVLP type system for the lathe, but my theory was / is, that if if can capture most of the waste using gravity then "funnel" that to a hose out let then it should collect most of the waste, I know it won't be good for dust but most of the dust occurs at the sanding stage and I might have to create some clamp to allow a hose to be placed right near the work.

Absolutely, and I guess you want full face protection when turning anyway, so an airfed mask would be ideal to protect you from the dust, whilst the funnel collects a decent percentage of the larger waste.

 

[Krysstel]

You may be interested in some of the things I posted here https://www.ukworkshop.co.uk/forums/extraction-lvhp-chip-hvlp-dust-or-both-t56466.html

Recently I updated the thread with details of a Thein Seperator I recently made.

Mark

 

[toast]

ive not tried using a long run of rigid ducting but ive just made a cyclone for my jet dc850 out of a wickes dustbin.
i used 2 meters of 4" flexible ducting as i didnt want to cut it until i decide how il have it setup/used and i havnt sealed any of the joints yet but it extracts from my table saw using 4".
i just tied it to the 2" outlet on my planer/thicknesser and it clears that ok, it was blocking up the fans output baffle before i made the cyclone.
i think there is a loss of suction but not too much, its cleaned the floor up no problem although has left some flakey rust chips so i doubt itl suck up bolts/screws but im fine with that.
i just need to make a port junction of some sort so i can use a normal hose for my router.
il just be putting it on wheels as i dont think it would cope with full on ducting with ports unless i took the filter bag off and vented straight outside.

 

[sploo]

You may be interested in some of the things I posted here https://www.ukworkshop.co.uk/forums/extraction-lvhp-chip-hvlp-dust-or-both-t56466.html

Recently I updated the thread with details of a Thein Seperator I recently made.

Mark

Nice build. I'm really considering a Thein separator. Looking again at Pentz's cyclone designs, I'm just going to struggle with the required height.

ive not tried using a long run of rigid ducting but ive just made a cyclone for my jet dc850 out of a wickes dustbin.
i used 2 meters of 4" flexible ducting as i didnt want to cut it until i decide how il have it setup/used and i havnt sealed any of the joints yet but it extracts from my table saw using 4".
i just tied it to the 2" outlet on my planer/thicknesser and it clears that ok, it was blocking up the fans output baffle before i made the cyclone.
i think there is a loss of suction but not too much, its cleaned the floor up no problem although has left some flakey rust chips so i doubt itl suck up bolts/screws but im fine with that.
i just need to make a port junction of some sort so i can use a normal hose for my router.
il just be putting it on wheels as i dont think it would cope with full on ducting with ports unless i took the filter bag off and vented straight outside.

Yea, a 1hp unit is probably going to struggle with any great length of ducting, so making it portable and getting it near your machines sounds like a sensible choice. Personally I'd probably still wear protection as I'd consider it (with a cyclone) as being a way to reduce blockage of the filter, as opposed to a way of reliably trapping the really fine dust; both from the point of view that it's hard to capture it at source, and that I suspect the stock filter wouldn't be suitable. I may just be being overly cautious - grown from too many years of breathing in clouds of MDF dust :-|

 

[toast]

i do still wear a mask to be safe, just a shame i never had one on site for the last 24 years while the chippies were cutting mdf and i was sanding it by hand before painting #-o

 

[sploo]

i do still wear a mask to be safe, just a shame i never had one on site for the last 24 years while the chippies were cutting mdf and i was sanding it by hand before painting #-o

Similar situation (though hobby rather than work): years of making loudspeaker cabinets from MDF. No mask. Lots of routing and sanding. Not clever at all.