Starting over on dust collection

tvrgeek

Scott
Corporate Member
My idea of a paint brush in the lower compartment of the band saw to "strip" off any remaining dust had little effect. Not much more I can do for now. A little bit of foam in one corner, a couple strips of foil tape and no dust accumulates. I just get a little over the top in crosscuts.

Reconnected my table saw to the ClearVue. I have one more trick to try to improve collection. That is to take their original output plate 4 inch flange and attach it to the door. Then a bit of flex host strapped to the trunion to focus the flow across the blade. I am going to contour the floor to better feed the duct. Like the band saw, the saw blade is quite a powerful fan and may not be easy to overpower.

Yea, going to have to keep the ClearVue. If I did not already have it, I still think a 3 or two two-motor Record Power systems are the way to go and have only one system. I am going to spend the money on further ambient filtering. I do need to fix the temporary 6 inch duct I put in before I moved the tools around and build a shroud over the Kapex.

Instead of running a duct to the drill press, I may just stuff one of my shop vacs under it with one of those ball-segment hoses and a small scoop. Quantity is so low, don't need to bother with a cyclone and instead of big bucks for the so called HEPA filter and bag, I am skeptical, I'll just exhaust through the wall to the outside.

Figured out the remote control for the vac. Now I want to do the same for the CV so I don't need to find where I left the remote and it does not like going through a wall anyway. Hardwire.
 

Alan in Little Washington

Alan Schaffter
Corporate Member
Good discussion- but chasing what in many ways is the unreachable. I've been at this since the early days- when Jim Halbert did the first experiments with a mini-cylcone (using a peanut butter jar!) and before Bill Pentz built his website. Like Bill, I was even blocked for awhile from Badger Pond and its progeny Sawmill Creek. ;) For the past twenty years I have been using a home-built, long-cone (3D) version of the Pentz cyclone and may be one of the first to actually incorporate the spiral inlet ramp (as Bill soon discovered and ultimately confirmed with a professor at Cornell, without warping it, you can't make a helix from a flat sheet of metal). Bill, and I along with a Fine Woodworking contributing editor were actually working on a Dust Collection book that never materialized due to differences of opinion.

I've written about this before, but for the best protection against hazardous dust and fines, you should wear a suitable mask and ensure your clothes, hair, etc. are free from dust before leaving the shop. Everything else is just a never ending quest.

For best protection from hazardous dust and fines you need to prevent as much as possible from entering the shop air space- capturing as much as possible at the source, and if possible vent directly outside. Anything else, like ductwork, cyclones, and filters reduces air flow and effectiveness.

Hobby woodworkers, driven by real and justified fear, dust collection industry hype, neighboorhood restrictions, and the desire to maintain comfortable shop temperatures without high HVACV expenses, are just about the only ones who try to filter and recycle the dust-ladden air. Industry feeds mountains of dust directly or via cyclones (initially borrowed from agriculture) and bag houses, into piles or trucks and has avoided much more. I have not researched what the EPA requires from industry now.

Capturing the dust must be done from all directions, from the spherical space around the source, not just at the end of the hose or duct, and that requires significant volume (CFM). With significant CFM produced by a materials handling motor/blower unit, you will normally have enough static pressure (SP) to avoid larger particles from settling in the ductwork. If you ever want to see in simple terms how effective your DC is- hold a cigarette or other source of smoke near a duct opening, them move it around the spherical space encircling the duct at different distances. Are you collecting all the nearly stationary smoke and from how far away?

To achieve good collection can be difficult with most workworking machines, though many of them make a half-hearted attempt to include adequate dust ports. Not only must machine port design be large enough not to restrict CFM it must also prevent moving dust with kinetic energy from spewing out. The cabinet, however, must also allow for adequate take-up air otherwise you'll restrict flow and CFM. So don't block all TS cabinet openings. Dust collection at the tablesaw and mitersaw is further affected by the presence of a spinning blade that can launch dust from the blade teeth and gullets at the operator at speeds approaching 150 mph (check my math) for a 10" blade at 5000 rpm the velocity far exceeds that of typical collection systems- approx 3500 fpm - 4500 fpm (higher in smaller diameter ducting) even at most over-blade pickups. One partial solution is to shroud or skirt the bottom edge of the pick-up like is done with CNC routers, to reduce the kinetic energy and velocity of the dust, yet still allow for uptake air. But shrouds are not always effective, even with shrouds, especially when cutting thick or irregularly shaped boards they don't seal well to the table. Vented blade slots are rarely effective due to the hole size that can't pass much volume and don't have the SP, and because they are often blocked by the stock. Most over-blade pickups use smaller diam. hose (I run a 3" DC line to my pickup). The same goes for mitersaw bladeguards, so all will likely benefit from higher SP. I have a deflection shield behind/below my miter saw that is connected to a 6" drop, but I also have a high SP central VAC line running to the blade guard. I also added a flexible extension chute to the blade guard to help guide dust into the port (some of the better mitersaws come with those now.) I also run the VAC drop line over my sanding table for handheld tools and to my benchtop hollow chisel mortiser. But no solution is perfect.

There are pics of all this stuff and more (like my autogates) in my media files, and some in albums (Shop Central Vac, Bandsaw Dust Collection, Blast Gate, Tablesaw Upper Dust Collection, Homemade Cyclone). Some used to be on WoodCentral in the TopShops contest but I have no idea where with their new website software.
 
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tvrgeek

Scott
Corporate Member
Alan, yes, I agree but that does not say we should not do our best.

Yes, a respirator is better, but can it be tolerated? How good. Even a P100, if it was a prefect seal, and as I have a beard, it can't, is only 95% @ .3 micron. Not enough as current medical research shows. Full face can seal better, but then I can't see. Half face is a problem with my sinuses and glasses besides totally dampening any enjoyment of being in the shop. I have tried an armful of masks and most are useless. The Trend and one of the 3M are the only ones close to working for me. The Trend for only dust and the 3M when I need carbon filtering. I have yet to find a proper P100 that fits under my welding helmet. If I can smell the dust or fumes, it is not working to the degree that is safe. As you say, better to collect at the source than at our face.

I have shown in my shop I can do better. Not perfect, as I don't live in Perfect, I live in Hillsborough. Lovely place but not Perfect. I have modified the terrible incompetent, and that is kind, designs of some of my tools. I have discovered which technologies do the best, even if far from perfect. I have watched dozens of "experts" on the WEB displaying what I know does not work, like a low lift system ducted with 4 inch pipe to a miter saw. Pretty, but totally useless. I have discovered, at least for myself as there is not original science here, most of the information is misleading, incomplete, or flat out false as they are just trying to sell you something. Yes, even the accurate information from reputable sources, Pentz, Oneida, 3M, is only a small part of what is needed. They tell you how to best use their product, not if their product is the most appropriate technology.

We need to demand better of our tools. With $2K for a band saw there is no excuse for a 4 inch duct intended for low lift, high volume, to be 60% or more blocked. No excuse for a $3000 table saw port to have not one, but two flat edges going into it. No excuse for a $1200 miter saw to have a port your little finger can get stuck in. No excuse for tools not to give valid recomendations of what is required for their design. This is not rocket science, it is fluids 101. Every Mechanical, Civil and Cem engineer takes this class. This are things any shade tree hot rudder understands.

Below is pictured incompetence at it's best. Dust port of a stamped sheet part, fancy latch, added molded plastic screwed on. Flat edges, cavity, and into a 4 inch exit. Source of the air is a couple slots in the door and gap under the front edge of the saw. All totaled even more restrictive as I can tell by opening the door. Don't say "cost". It would be cheaper to mold one piece duct with a nice 1/2 inch radius. No extra sheet metal, no extra screws, no extra assembly process. Incompetent. Never mind the duct is several inches from the floor so any airflow there is just causes several inches of dust to pile up. Saw Stop overarm guard. Yea, the far end has a big gap to allow airflow, but the left a huge gap out the front where the bade is jetting that high speed stream. Both sides move together so when cutting a short piece, the guide lifts off the side allowing more dust out. Big 4 inch attachment. OOPS, down to three at the guard and flat edges going in so it restricts the flow further. No mater how many CFM open port a collector has, it is not going to pull much with 4 or 5 inches of lift through that.

Yes, the blades are very high speed fans. I have some ideas to use that to some advantage.

Then we get to just plain old fraud. "True Hepa" is not H13. "HEPA style" is meaningless. Lots of total BS terms like "hyper" "extra" "exceeds" tossed about. Monitors that measure PM2.5 that is barely in the dangerous size range if in fact they actually did. Some are shown not to even have the real sensors in them. The one I am sending back does at least have the sensor, but it reads "good" when I can see the dust cloud! Even Oneida. The new to great acclaim 2.5 inch cyclone is not. It is set up for a smaller hose to go inside the 2.5 port and adds a sharp step in the process. What is new about it is it is cheaper to make and costs more.

So, my high lift system will exit to the outdoors. Probably in EPA violation. My 3M ROS does a great job at collection compared to others I have had. Shop clean-up hose, router table, and port on the miter saw, all go outside as total volume and noise are not too bad. A single vac was not quite enough for my drum sander. Two were, but as I am now going the two system route, I will use the CV on it. I may get the bigger Ridgid or Bauer as they have hose connection exits, don't need the "hepa" if it was real anyway, and they have higher flow than my Fein. I'll keep the Fein/cyclone for portable and the other end of the shop where I do metal work.

The big cyclone is only MERV 15. Adding a large enough bank of H13 filters is very expensive but I don't see an alternative. Enclosing and porting outside would limit the hours I can use it and my HVAC with additional de-humidifier could not keep up.

And I continue to migrate to more hand tool than power tool. I break down sheet goods outside. I use the band saw more than the table or miter saw. But I will continue to improve both dust collection systems and all my tools. If I can half the dust, then total exposure is halved.

So far, I continue to think a 3-motor or two 2-motor Record Power systems is the best available technology for a one man hobby shop. If you know anyone in the vacuum industry and have a source for 100% duty cycle high lift vacuum motors, one could do even better DIY. Even their data I don't believe. First, they have no back-flow dampers so if running one motor, flow is reduced by backflow through the other motors. ( They admit this but still hold to their full flow numbers) Second, they don't explain how three motors, each pulling 114 CFM can magically pull 850 working together. Shop vacs have even worse duty cycles. At least the big CV is 100% so I can spend two hours planeing rough stock.
 

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tvrgeek

Scott
Corporate Member
Table saw is getting better. I made a tray for the bottom. Does nothing for topside, but now the base stays virtually clean. Holes in the door "scrub" the floor. 6 inch port as before, but now level with the floor so no dead zone. Holes in the ZCI do pull some air, but probably insignificant. I am going to make one with a screen in that quarter. There is enough flow that a screen in a section of the top might work. The brush on the overarm does at least 75% in blocking the forward spray. Back and right side are open for airflow. I may see what trimming the rear half of the left side does. A little more air and not where the spray needs blocking. With the guard in place, one can raise the blade a little more. Slightly better cut and less cutting at a time. Maybe just above the bottom of the gullet. I normally ran just below the tooth. The CV is still starved for flow with this config so a directed port behind the motor may still have some possibility.

I rarely use my sled. Some have made a drop down cover with hose. I was thinking of one with a big slot that the overarm can ride across.

What would a pan like this cost the OEM? Pennies. They already put in a steel pan. It could easily be replaced by a two piece ( fits through door) vacuum formed or blown ABS, Poly or something. Easy and cheap. Would it be a good advertisement/sales pitch to show your cabinet stays clean? I bet so. Port could be made the same way, either two , 4 and 6, or a stacked one the user trims. Cheaper than the sheet metal and port held on by four screws. They could make "adjustable" ports in the door you tape up or expose labeled for the size of your duct collector. I still have my ramp beside the blade to test. The blade should have enough "fan" to force the dust from the gullet if the gap is small enough. Location is the issue. I think I can mount something on the riving knife arm.
 

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Alan in Little Washington

Alan Schaffter
Corporate Member
I think you have discovered for yourself and accurately described the myriad of the problems, though not necessarily effective AND convenient solutions.

Frankly, in many cases they are are mutually exclusive, e.g. a TS over-blade pickup that seals well and catches all or most of the dust, but also is convenient to use, can remain attached, moves freely over the stock, and fixtures like mortising jigs, miter gauges, etc. AND allows you to see the leading edge of the blade to position boards to the blade using a registration mark. My over-blade guard fails miserably on that last point. I made the guard skirt from bristles cut from a broom (brush?). They are too stiff and unintentionally and easily "trimmed off" by a sharp saw blade :( I have some brush material (for conveyors?) that has longer and finer bristles, but haven't gotten around to installing it. My guard is mounted to a length of 3" thin wall PVC that is mounted to the ceiling. The lower 12" is hinged and easily lifted up, out of the way for all but unusual situations. When folded, a mag microswitch breaks the circuit that operates the blast gate located behind the kneewall. It takes more effort- I must loosen sway braces- to adjust the vertical position of the guard or raise it totally up and out of the way. It can be moved side to side somewhat to adjust for lateral saw position. But back to one of my original points- it took a lot of thought and work for something that really doesn't work all that well and that it not used as often as it should be. When I run to the saw to make a quick cut, I'm not inclined to spend time to adjust the blade guard.

Probably the best thing I did to improve dust collect and counter my laziness, is to automate my blast gates and DC- they open (and the DC starts) when I turn on a machine. It is a very simple system using current sensor switches mounted at each tool's wall outlet. 24 VDC operates SMC solenoid air valves which port 15 psi shop air to BIMBA pneumatic cylinders that operate (open and close) the gate slide. The gates close when the machine is turned off but the DC stays running- I could have used time delay relays to delay closing the gates to turn off the DC, I'm slow enough to turn machines off that dust will make it to the blower and cyclone before I turn the machine off. I leave the DC running to prevent rapid cycling of the motor when I do repeat cuts or if I'm going back and forth between the jointer and TS. I don't have any fancy PLC logic circuits and except when I inadvertently knocked the wires off a solenoid valve (all are mounted behind a knee wall) I have never had a problem in over 20 years. The only exception to the above process is at the miter saw - Since the process there involves short on/off cycles I went with total manual activation of the blast gate and the DC. I use two switches- one controls the DC and big gate, other turns on the central vac. There is a manual gate on the vac line.

Yes, there continues to be a lot of bad info out there. Even Bill put out a few questionable bits, e.g. He said tool drop blast gates should be placed near the wye where the drop joins the main. That works, but is not always convenient and not necessary. When the gate is at the tool it is easier to reach so you will be more inclined to open and close it. When it is closed there will be no flow in the drop- it will be invisible to the DC- so it will have no impact on CFM or SP anywhere else in the system.

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tvrgeek

Scott
Corporate Member
Fortunately, the SS overarm swings out of the way really easily. I am getting used to it. I do want to add some sort of rack and pinion to adjust it left and right for push block clearence. It's sides are articulated so short door sweep brushes have worked out well.
 

tvrgeek

Scott
Corporate Member
Plan e, f, g, whatever.
I have re-arranged to have room for my small cyclone to be behind my outfeed and a strait shot on the 2 inch line input. I am then going to run strait up though the ceiling into my store room and place the vacuum there. Only about 7 feet of vertical. This puts the cyclone at the end of the run eliminating some convoluted corners where it was pulling from the middle. So the "HEPA" not quite exhausts the super fines from sanding into the store room vented outside. Quieter. Healthier.

Some data research.
Shop vacs can pull between 50 and 180 CFM but typically around 60 inches of static lift
Dust Extractors from 120 to 160 CFM and 80 to 100 inches static lift
Home central vacs from "maybe" to 215 CFM and 200 inches static lift.
Industrial 100% duty cycle vacuums the sky is the limit, but so is the price.

So for small port ( less than 4 inch machines) there is more than enough power available for long runs.
 

tvrgeek

Scott
Corporate Member
I'll probably read this whole thread later but I thought I'd stop in to say the Dewalt 12gal STEALTHSONIC (Lowes exclusive?) is a fantastic vac when paired with a Dust Deputy 2.5". I'm planning to upgrade my bucket to an Eagle 20gal (Eagle Mfg Open Head Salvage Drum, Polyethylene, 20 gal, Unlined, Yellow 1654 | Zoro) but I know I also need the other half, a high flow / low static pressure dust collector for use with my planer.
Nice looking drum. You can get an adjustable over-vacuum valve from Stockroom Supply so you don't crush it.

DeWalt, 105 CFM and only 70 inches of static lift. Typical for a mid-range shop vac. Way short of a proper ( and much more expensive) dust extractor and pretty short of my Ridgid. It is only a shop vac. No cyclone. How the performance may drop if fitted with a HEPA bag/filter is unknown. Of course, stuffing it in a cabinent with a WYNN H13 filter is another and probablly better way to go. Big thumbs up to them for "quiet" Might consider the ClearVue mini cyclone rather than the DD 2.5. I may send my 2.5 back. If you are going to the pic-nic, I'll give you a deal on it. I could use it on the Ridgid shop vac for the drill press but in actuality, considering how little debris I have there, a bag is a better option.

Don't know which planer you have, but the DeWalt 735 has a high flow fan built in and could just as well work with a bag as a dust collector.
 

prototype3a

Drew
User
The Dewalt is QUIET. REALLY QUIET. That's the tradeoff you make since it it only 100-ish cfm. I still have my "old" Craftsman 12gal that is probably 180cfm and it SCREAMS. I'm designing some adapters for 3d printing so hopefully the Dewalt will play nice with my RO sander as a "dust extractor".

Huh. "Dust Commander Anti-Crush Valve" I figured something like this HAD to exist but I couldn't find it the other day.

I saw your preference for the ClearVue after I posted.

I have a Powermatic 100 planer.
 
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tvrgeek

Scott
Corporate Member
Well, this step failed. I wanted to see how the air filters that filter down sub .03 work. The WEB is full of BS marketing and fantastic claims. One company stood out as being an actual working and well built unit. IQAir. Very expensive. $900. As we both have bad allergies, thought if it worked in the house, it would work for the ultra fines my cyclone and ambient filter can't do. I know nothing about the filtering but it is LOUD. I mean really loud. Drown out the radio loud. Only on low, 35 CFM can you be in the same room with it. I guess if you were gone all day it could run, then turn low at night. Sending it back.
 

prototype3a

Drew
User
Seems most people install that "anti-crush" valve in the lid of their bucket but it seems to me that it would be better to install it on a Y pipe leading to the inlet of the cyclone. With the valve on the inlet it would keep air flowing through the cyclone but still prevent the vacuum pressure from getting too high. When I was looking for such a thing before, I was thinking about pilot operated pressure regulators and turbocharger wastegates or blow off valves.

It seems there are STL files available to print a similar valve all over the internet. Printables I think I may design my own version to go on the inlet of my cyclone.

For what it is worth, below is a cross section view of one of the adapters I was designing to have 3d printed. It would adapt from 2.5" standard shop vac taper down to Hi-Tech Duravent 1.5" Super Vac-u-flex hose. I've designed an adapter for the other end of the 1.5" hose to fit my Bosch ROS65vc. The integral vent holes should allow bypass air to keep the vacuum happy and also prevent crushing the cyclone bucket.

As far as I understand them, cyclones separate fines better with higher airflow velocity (up to some limit for the size of cyclone) and so, I figure allowing bypass air should keep the airflow through the cyclone higher while still pulling dust out of the sander. A friend of mine said he actually had problems using a dust extractor with his RO sander because the high vacuum of the dust extractor was basically pulling the sander down onto the workpiece. So, I'm very curious how this will work with my sander at a much lower static pressure.

1716118539077.png
 

tvrgeek

Scott
Corporate Member
My 3M ROS, using the Extract mesh disks is not a problem with full vacuum. Paper disks are, but that is why there is a bleed port on my hose. My Bosch ROS has a bleed port cast into the base.

I have the same understandings on cyclones. They have an optimum range. The physics probably get really complicated fast so I'll leave that to ClearVue and Oneida. I also know the taller the cone, the more effective.
 

tvrgeek

Scott
Corporate Member
The high lift, 2 inch PCV, CV mini cyclone, Fein Turbo II vac is working just fine with the vacuum in the attic storage room and the cyclone down where I can empty it easily. As I am still using a 5 gallon bucket, I'll order an over-pressure valve from Stockroom Supply. Someday I'll make a collection bin that can withstand full vacuum. Next is the remote control. I have yet to figure out how best to attach the switches to the gates. Epoxy maybe. Anyway, they just are in parallel with a 5V wall wart to control a high current SSR. Very simple. I might change to a battery. It would probably last forever.

On to connecting the Ridgid vac to the drill press and vent outside.
 

tvrgeek

Scott
Corporate Member
Did some research on raw vacuum motors. Similar to what Record power uses, central and industrial vacs. Even automotive flow benches use a bank of them. ( 17 at Gayle Banks) They run about $100 or so each. Anyway, they come in 1,2, and 3 stages. The more stages, the higher the lift. From 80 to 175 inches. They all only pull 100 to 130 CFM. Duty cycle varies. Getting actual specs is difficult as most sell "fits X, Y, and Z" I did not fine much tradeoff between lift, power and stages. Seems for the function of a vacuum cleaner, the requirements are pretty well narrowed. Would four of them , wired series/parallel giving around 500 CFM be enough for the high flow tools? It might be because it would overcome any ducting loses and some of the really bad machine designs. If you wired 220 with a common ground, then with some switch creativity you could run any number of motors depending on the tool. There is one step up but usually 3-phase power and huge, along with 4 and 5 digit prices for some industrial applications. 100 inches and 1500 CFM? Not going to happen.

Fein in the attic, can't hear it at all. :) How much CFM I don't know as it maxes out my meter on the hose but it seems to work on all the tools I have it plumbed to. My 6 inch test tube is not long enough so I get variable readings. Need to get a 6 foot bit of duct if I want to get precise. I did order a relief valve from Stockroom supply so I don't crush my bucket. Don't know what to set it to, but my Fein did crush a bucket.

So not ONE dust system as I had hoped, looks like I will have THREE. Fein/CV mini for the ducted 2 inch high lift tools, Big 5 HV CV1700 6 inch for BS, TS and mobile planer, jointer, sander, and a third cheap Ridgid vac, no cyclone, dedicated for the drill press.

So, IF I did not own the ClearVue, did not own a Craftsman and Ridgid shop vacs, and did not own the Fein, I think a four motor, 500 CFM, 120 inch lift system could do what I need in a one man shop. I would DIY the entire system, plumb in 2 and 4 inch PVC. We are talking well over 5 HP here. I sure understand things a lot better now and hold my viewpoint we should complain to the tool makers about incompetent design and advocate the extractor makers for better description of technology vs. use case. It should be made clear the differences from MERV less than 15 ( useless) MERV 15 about all you can get on a big collector, "HEPA like", true HEPA, actual HEPA 13, and filtering below .03 micron. Not even too sure how to do that. Electrostatic maybe. Actual safe air would seem to imply a lot of outside exchange ( unless you live in Beijing or next to a volcano) and huge burden on HVAC and RH control.

Unless I discover something else new, I'll wrap this up. I still have some machine mod ideas to test. I also have my next couple of woodworking projects on the table. More picture frames and a cabinet for the sunroom. Oriental or Arts and Crafts? Have not decided.

PS,
The IQAir home "exceeds medical HEPA" unit I am sending back. At 40 CFM you can sleep with it, but that is not high enough to be useful. Level 2 you don't want to be in the same room. Level 6, full 400 CFM, it makes as much noise as a shop vac. If you were gone all day you could run it full, then off or speed one while home and it might well be a very good addition to indoor air quality especially if you live in a location with very bad air.
 

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