Dust collection

[Peter Christensen]

A hot wire anemometer is a better tool for checking velocities in DC pipes because it blocks less of the duct causing turbulence that the fan ones do. Some hot wire types are not able to read high enough so you need to have a test pipe of 8 or 10 feet with the anemometer nearer the end of the pipe so the incoming air has a chance to settle and straighten out. An average of several readings across the diameter is needed too. There are some that can read the higher velocities in DC pipes where you wouldn't need the test duct like this one. https://www.ebay.ca/itm/LCD-Hot-Wire...QAAOSwhcJWIb4x

Or this one. https://www.ebay.ca/itm/Hot-Wire-Dig...0AAOSwqd1ZyivX


This one is nice because you use it with your smart phone. It may need the test duct though. https://www.ebay.ca/itm/Testo-405i-H...EAAOSw0UdXwDCT

[Ted Derryberry]

Saw dust used to pile up in my old cabinet saw but I still ran the dust collector as it kept the fines from floating into the air. I actually preferred shoveling out the bottom of the cabinet over emptying the dust collector so it worked for me.

[Larry Frank]

I used a hot wire anemometer to test my system and measured several spots across the diameter. I used the data to make a performance curve of static pressure versus cfm. Now, to determine cfm, I just check the static pressure and use the curve to find the cfm.

I also did a test with a hand held anemometer and found you could get numbers all over the place and not reliable.

[John K Jordan]

A hot wire anemometer...like this one. https://www.ebay.ca/itm/LCD-Hot-Wire...QAAOSwhcJWIb4x
...

Peter, do you have experience with the ones you linked? The price certainly looks good but reviews I found on the first one were not encouraging. (Amazon https://www.amazon.com/Perfect-Prime.../dp/B077VQ8HC2)

From my initial looking around it appears most with good reviews are in the $250 to $500+ range, however at that price the number of reviews are few (not surprising with such a specialized tool!)

Is there any place to read unbiased reviews? For example, this one is inexpensive and has good reviews on Amazon, although only a few: https://www.amazon.com/TPI-565C1-Ane.../dp/B0095X8YZG

JKJ

[Peter Christensen]

Actually John I haven't. I would get the Testo because on the Aussie WoodWork Forum a guy had one and was testing his system with it. Because it sends the data to a program on the app it saves the data that if desired and can be played with later. I just checked the spec on it and it can measure to 6000 feet per minute so you wouldn't need to make a test duct either and it reads higher than the other self contained units I linked.

[Ole Anderson]

Here is my advice: Consider the dust collection system your most important shop tool, the tool that will compliment all of your other tools. The tool that will make your shop cleaner, your work flow smoother and your health, well healthier. If you are in a position to do it, do it right the first time and you won't regret it. That means getting a cyclone that can pull 800 cfm at 8" of suction. That 1200 cfm bag unit, well it might get 800 cfm at 4", not enough. Look for something about 3 hp. Use snap lock steel duct and size your main at 7", the sweet spot for 800 cfm velocity. Buy your pipe and fittings from a local HVAC supplier or better yet search out a local sheet metal shop for good pricing. No huge shipping costs. https://sawmillcreek.org/showthread....all&highlight=

[Jim Becker]

Here is my advice: Consider the dust collection system your most important shop tool, the tool that will compliment all of your other tools. The tool that will make your shop cleaner, your work flow smoother and your health, well healthier.

This is absolutely a very accurate statement...

[Bill Space]

I have no argument with any of the great advice and guidance above.

But I have one small hair to split, something that popped into my mind a while back. That is the difference between dust collection and air purification.

To me, dust collection is gathering up most of the chips produced when we cut wood. It does not really consider the health concerns of small dust particles that may end up floating in the air.

Air purification rides on top of dust collection in my mind. It removes the small particles that may be hazardous to our health. It is the ultimate solution.

The systems we each install exhibit performance somewhere between the ultimate and nothing.

But each time a dust collection thread comes up, it seems to evolve into an air purification thread. This is fine, and perhaps helpful to those who have not considered the importance of air purification.

But I can’t seem to equate dust collection and air purification as being the same thing. I see dust collection as a first step, to be enhanced into an air purification system if one can afford/desire to do so.

But ofter these threads seem to drift towards something like “anything less than good air purification is a waste of time!”

But they are two different breeds of the of the same animal (or a continuous spectrum from nothing to everything). Both serve a purpose.

How crazy am I?

[Rod Sheridan]

Bill, you're not crazy, however from a technical perspective dust collection is the collection of fine dust, which also includes chip collection.

A dust collection system should do both, at source..............Regards, Rod.

[Marty R Schlosser]

Hey, Bill,

To me, I equate the term "Dust Collection" to mean "Dust and Chip Management" in my shop.

As Rod and others have stated here, you have to look at this from a systemic perspective. And if all a system does is look after the chips, it is woefully inadequate because that person's health is being compromised. In my shop I use brooms, a shop vac outfitted with a Dust Deputy, a central Oneida cyclone with a HEPA filter, modified hoods on nearly all of my machines - big and small. And I wear a dust mask whenever I am doing anything that generates a lot of fine dust that always seems to get into the air (the worst one in my shop is my lathe while I'm sanding).

Oh, and by the way, I don't think you're any more crazy than the rest of us! You're in good company!!

I have no argument with any of the great advice and guidance above.

But I have one small hair to split, something that popped into my mind a while back. That is the difference between dust collection and air purification.

To me, dust collection is gathering up most of the chips produced when we cut wood. It does not really consider the health concerns of small dust particles that may end up floating in the air.

Air purification rides on top of dust collection in my mind. It removes the small particles that may be hazardous to our health. It is the ultimate solution.

The systems we each install exhibit performance somewhere between the ultimate and nothing.

But each time a dust collection thread comes up, it seems to evolve into an air purification thread. This is fine, and perhaps helpful to those who have not considered the importance of air purification.

But I can’t seem to equate dust collection and air purification as being the same thing. I see dust collection as a first step, to be enhanced into an air purification system if one can afford/desire to do so.

But ofter these threads seem to drift towards something like “anything less than good air purification is a waste of time!”

But they are two different breeds of the of the same animal (or a continuous spectrum from nothing to everything). Both serve a purpose.

How crazy am I?

[John K Jordan]

Air purification rides on top of dust collection in my mind. It removes the small particles that may be hazardous to our health. It is the ultimate solution.
...
But I can’t seem to equate dust collection and air purification as being the same thing. I see dust collection as a first step, to be enhanced into an air purification system if one can afford/desire to do so.
...
But they are two different breeds of the of the same animal (or a continuous spectrum from nothing to everything). Both serve a purpose.
How crazy am I?

My take on this:

You're not the least bit crazy, unless critical thinking is taken for crazy these days! What makes all this very hard is that I understand the permanent lung damage from fine dust may take decades to show up and when it does it's way too late. I personally know and know of several local people who had to quit working with wood completely because of lung issues. One guy, an amazingly creative woodturner, had to give up woodturning and take up metal turning to satisfy his drive to create.

Bill Pentz points out that inefficient collection is actually just visible sawdust and chip collection. Insufficient air flow and poor collection at the source does nothing for our lung health since it doesn't pick up the fine particles. Some are even worse than none if they just blow the fines around (like a bag collector). Bill's strong sermon is to somehow create a system that DOES pick up the ultra fine particles before they get into the shop air.

Air filtration after the fact has been shown to work (my Dylos particulate monitor proves this) but it can take an hour or so to remove what's floating in the air and which you are breathing for after cutting or sanding. Very few people take the effort to design and use effective fine dust pickups at each machine and spend the money for the proper ducting and a collector powerful enough to get most of the fines. If they see the coarse stuff being picked up they are happy, unfortunately, perhaps in ignorant bliss. And although fine dust in the air will eventually settle on something it can get moved around again when disturbed.

Pentz recommends a good cyclone, modifying all machines to accept 6" dia ducts for sufficient airflow, devising special shields and pickups, dumping all exhaust from the DC outside instead of filtering and returning the air to the shop, and wearing a respirator. Almost nobody does all of this. Another great technique is to use big fans to blow all shop air outside during and after working, moving clean air in from the other end of the shop. A friend of mine works at the lathe with a powerful fan like this directly behind the lathe. Unfortunately, this is impractical for most people, especially in sub-zero or 100-deg temperatures.

Some machines are easy to catch all the fine dust. Some pickups are possible but a pain to use and get in the way (e.g. using a hood over the TS blade such as the Excalibur.) Some are almost impossible, such as power sanding at the lathe.

Any DC might be better than none but I don't know of anyone who does dust collection "right". For those who are concerned about lung health: wear a respirator (not a paper dust mask). I know mine is not perfect so use the 3M respirators with P100 filters during and after sanding. I use a 5hp cyclone with 6" ducts. I monitor the air with the Dylos and can tell by the numbers when the levels are as safe as they are going to get. The Dylos will tell me when the air is unsafe, at least the air close to it's intake port.

JKJ

[glenn bradley]

A lot of dust collection threads seem to go the way of the MPG discussions of the 1970's. All sorts of varying attempts to put lipstick on a sow. Unusual claims backed up by poor science and all that . Even though we know that dust collection should be one of our primary spend areas in a shop of any kind that creates a harmful atmosphere, we resist. Even those who will spend big on machines will cringe at the cost of decent dust collection.

There are a lot of things one might want to have but, if the money isn't there, you do what you can. It is a health decision and not one that you get a do-over on if you take a hit. I'm not one for doom and gloom over the dangers of dust and vapors but, I do try to be realistic.

You can easily augment a sub-optimal system with a respirator BUT, you do have to wear it faithfully. If you live where the weather (and your neighbors) are good you can open the doors and aim fans out of them. The thing you don't want to do, is nothing. If you can't build a proper system for your situation right away, take some steps that will serve you now and plan/save or build in steps as you can. Above all, stay safe and have fun.

[Ted Derryberry]

Ideally all dust would be collected completely at the source. But then there is reality.

[Brian Byers]

I just wrote out a long reply and it got erased. I'll try a shorter reply. My wife's giving me 7k out of our house refinancing for tools to make a little more $. I was forced to sell shop full of tools when I got Leukemia (mostly Jet and American made Delta) I've got a few tools now. I've got to keep it cheaper. Maybe I can incorporate the good advice into making a cheaper system. Would a single stage DC unit with upgraded filter and a super dust deputy ($179) on a mobile stand with 6" hose work. I need some tools to make money. I've recently been told I should get a high end sander and extractor for my shop too. I'd hate to have my wife come into my shop in hopes of seeing me make money only to find me out chasing dust bunnies with a 6" hose attach to a cyclone😂😂😂 thanks Brian

[John K Jordan]

I just wrote out a long reply and it got erased. I'll try a shorter reply....

I hate it when that happens. When writing a message before I do anything I usually use Ctrl-A/Ctrl-C to select all the text and copy it to the clipboard in the rare event the text disappears before I can post it. This has not been a problem since I quite using the Enhanced editor in SMC unless I'm switching tabs in Safari on an iPad.

...Would a single stage DC unit with upgraded filter and a super dust deputy ($179) on a mobile stand with 6" hose work....

As mentioned earlier, avoid breathing the fine, practically invisible dust. If there is any doubt it is always safe to wear a good respirator when working in the shop, although inconvenient. The one I showed earlier is widely available, inexpensive, and comfortable to wear.

JKJ