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Thread: Leaf blower dust extraction??
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31st May 2019, 06:51 AM #1Intermediate Member
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Leaf blower dust extraction??
So Im planning to make my own dust extraction system using a leaf blower and am wondering if anyone else has done the same?
I am documenting the process on my youtube channel, heres the link to the first video where I mock it up: https://youtu.be/v4PLKKGtplQ
Im also planning on using one of the cheap chinese Cyclone off Ebay, Does anyone have any experience with these? Would a 60mm Hose be enough for the System?
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31st May 2019, 08:32 AM #2.
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Sorry to be the bearer of bad news but if you are hoping to capture most of the fine dust generated by woodworking machines then you will be disappointed.
Although they claim a maximum air speed ~350 km per hour this is for unrestricted flow.
Leaf blowers use relative small impellers so simply don't move enough air under pressure to act as replacements for conventional wood dust extractors.
As soon as a filter or cyclone is placed in line with the air from a leaf blower the air speed will drop significantly.
Comprehensive dust extraction needs about 28,000 L/min at the source of the dust for dustier machines, to be confident of capturing all the fine dust they generate.
A certain amount of pressure is required to force air through fine dust filters (leaf blower filters are usually very coarse) and even more pressure is needed to move air through a cyclone.
Under real conditions 28,000 l/min requires at least a 3HP motor and 150 mm ducting.
100 mm ducting only moves around 1/3rd that of 150 mm ducting so 60 is nowhere near enough.
The other thing is noise - powerful leaf blowers are very noisy - much noise than conventional dust extractors.
What will happen is you will pick up the visible sawdust and leave much of the fine dust behind in your workshop.
You could get around this by installing additional ventilation such as exhaust fans, and provided you do not use very dusty machines too often you should target 20 room air changes per hour.
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31st May 2019, 08:33 AM #3SENIOR MEMBER
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I have two fo the cyclones working with shop vacs and they are great little suckers, dependant on the vac power. You will get lots of input from this forum some helpful some dependant on your dollar spend, cheers.
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31st May 2019, 10:26 PM #4Intermediate Member
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Ok thanks for the input guys!
I have actually had the leaf blower mocked up as a dust extractor before and thought that it worked great! I actually had to turn the speed down because the vacum was distorting the hose's, turning it down then also made it much quieter than my shop vac.
I will have to mock it up in a more realistic way to be sure but im quite confident it'll work great. Time will tell
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31st May 2019, 11:40 PM #5GOLD MEMBER
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I think you're missing the point. The bit you can't prove whether your dust extraction is good or not, because you can't see it, is the bit that is bad for you - the fine dust. And you need to move lots and lots of air (large volumes) to move the stuff you can't see. And your leaf blower is high pressure but low volume.
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1st June 2019, 07:26 AM #6Intermediate Member
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Like I say time will tell! I have had this mocked up though in the past and it seemed to work really well, I'm planning on using a couple of FY1114/10 Hepa filters and they remove particles down to 0.02 microns. This is obviously not going to be a replacement for a full size dust extraction system as you described above, but more a upgrade over a standard shop vac dust extractor.
As you can probably tell in my videos my workshop isn't all that big, so Im working with the space I have.
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1st June 2019, 10:27 AM #7.
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Shop vacs are evil things as they can make more fine dust fine than they collect.
They do this mainly by mincing coarse dust into finer dust.
A leaf blower also does this.
Even if the dust through the vac is filtered, the motor itself is also source of fine dust particle generation ie it also minces coarse into fine dust.
Unless the motor cooling air is filtered the best place for any extractor (Vac/Leafblower/DC) is outside a workshop
Shop vacs also don't collect anywhere near enough air/dust from machinery but are OK on some power tools so it depends what the leaf blower will be connected to.
Even if you can double/triple/quadruple the flow (which I doubt will be possible through 65 mm hose and the back opening of the blower) it still won't be enough for machinery.
The first thing I would do is make a U-tube manometer and measure the static pressure/vacuum of the blower. This will provide some immediate indication of what real air flows will be possible and what filters will do to the air flow.
You might want to think a bit more about whether the FY1114/10 HEPA or similar filters are suitable as they are not designed for vacuum systems but for air purifiers in air that las a low dust load and may clog too quickly. From what I can see they are not designed to be cleaned but replaced.Instead I would suggest looking at using filters designed for vacs that can be cleaned. The 0,02 micron removal is a bit of a gimmick - note: they don remove all these particles just some of them The true specification for those filters is 99.95% at 0.3 microns. Many ordinary filters can remove some small particles once they are conditioned ie partially clogged. Then the question arises, is it necessary to remove such small particles since there are already trillions of these in the air. These particles exhibit gas like behaviour and thankfully as many as are breathed out are usually breathed in. The target wood dust that is known to cause problems is around the micron range 5 - 0.5microns since less are breathed out than are breathed in.
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1st June 2019, 06:44 PM #8Senior Member
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I have a rather minimal dust extractor - 1 HP auctions $40 and hardly used . If you can locate something like this outside the shed under some sort of shelter then at least its not realeasing very fine dust that comes through the filter bags. Yes a bit more ducting which will slightly decrese efficiany however with the cloth bag filter units- as most units are. Better outside than in and while you're at it stick the compresor there too -save floor space. I know there is many vac system units that are HEPA accredited - most dust extractors aren't, but a dedicted unit will deal with your heavy unless you are only talking things like random orbit sanders. By the way it's the fine that will get ya. Blackwood and others require particular vigulance as the particles are barbed (pick up blackwood dust left by a sander- sticks together likes therestuck together like spider webs) nota chemical threat -more the structure- hooks into the lungs.
Have been in the industry for decades and might or might not die early as a consequence. Smoker, drinker, would like to be a womeniser -the missis wont let me. All the that they say now is probably true. So good on ya for whatching yaself.
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1st June 2019, 07:25 PM #9GOLD MEMBER
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With all due respect, this is not helpful! The problem with what he is doing is putting all of this together and creating a YouTube video of it showing “how good” it all is. This creates the problem of others viewing the information and then believing it’s true, when in fact is completely wrong.
People need to listen to advice that Bob is giving for free and save not only their life but those who view and act on misinformation.
Fine particles of dust (invisible) is what causes you problems not the stuff that you can see being sucked up the hose. Yes you can get hit by a bus tomorrow but for goodness sake, listen to those who know how this stuff works, don’t go off on your merry way with no clue of what you are doing and then put it on YouTube and “claim” that it works!
Fairdinkum!
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1st June 2019, 10:05 PM #10Intermediate Member
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How can you judge something that isn't even finished yet, people are always afraid of new things and unfortunately many people will be put down by that and follow like sheep. NOT ME!
To be Clear:
I have experience in this!
I have done my Research!
It will be documented and tested on video for all to see!
I do however welcome Creativity so thanks to all who have messaged me with ideas!
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2nd June 2019, 03:51 AM #11GOLD MEMBER
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Basher when you do your testing better have a particle counter to see how much bad dust you are not getting and what might be leaking from your cobbled up machine. Unless of course you have a wireless mic inside the dust mask you'll need to be wearing all the time while doing demo videos. You can get one for about a hundred bucks.
Youtube has at least a half dozen videos on making DC's from leaf blowers but you seam to be the first to try and throttle the airflow back by sucking through a tiny cyclone. Before you go much further you should take you test equipment and do a static pressure test on the leaf blower to see where it falls when compared to HVLP DC's at 8 to 15 inches of water column and the 80 to 160 inches of water column a HPLV shop vac produces. If you aren't close to the shop vac range you aren't going to get the performance you think you'll have.
This guy has joined this and other forums in the last few days with the sole purpose of getting people to watch his Youtube stuff. He posts nothing in the form of detailed write ups and pictures. Just baits people and a link to his videos. He has started by doing it in his introduction, a scraper thread, a CNC thread and this one. Had he joined and for a couple months contributed with posts that had information and helped people without any links or references to his Youtube channel then I wouldn't be so bugged.
Pete
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2nd June 2019, 09:05 AM #12GOLD MEMBER
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I guess it’s one way to make money Pete. Not a great way, people’s lung conditions are not really something to be messing with without first quantifying the theory prior to creating a video for all to see.
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2nd June 2019, 09:46 AM #13GOLD MEMBER
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2nd June 2019, 10:31 AM #14.
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Static pressure will be just a starting indicator.
The next critical factor will be total Air flow
Even with a high static pressure the small impeller used by leaf blowers simply won't rotate fast enough to draw enough air through the blower to be of any use in dust capture from machinery. It might be OK on Power tools.
The next factor is the fan curve.
This the pressure the impeller can generate while it's moving air and is presented as the actual air flows ranging from unobstructed flow to fully obstructed flow. lThis is critical for pushing lots of air through a filter or a cyclone. Single bath room fans can move a lot of air but as soon as a half decent filter is place in front of them the air flow falls dramatically. Unless cyclones are designed specifically for an impeller then they will rob as much or even more flow than a half clean filter.
Finally as you say some real dust measurements would be useful.
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2nd June 2019, 10:31 AM #15GOLD MEMBER
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Don't get too excited guys, so far all he's done is attach a cyclone to a collection drum. If you didn't have a redundant leaf blower lying around would you be better to purchase a shop vac to do the job or a leaf blower? I know what I'd be buying.
Interesting that he's using a cyclone that's really only suitable for a shop vac and he's got a shop vac. You can buy a larger version of that cyclone (75mm ports instead of 50mm), but he hasn't even gone to the trouble of getting one of those to improve his chances of success, from virtually none to bugger all. As to the idea of using the leaf blower collection bag? OK leaves won't escape it, but just about everything else will! Curiouser and curiouser.
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