Dust separators

[tablesawtom]

There is a lot of dust separator up grades on YouTube lately. It is probably because I watch them, when they appear but I am not sure.  One was complaining that he got tired of having to empty the plastic bag, so he  put on  an after market cyclone separator, which dropped the chips into a plastic bucket.  My dust collector  separates the chips from the fine dust and I do have to empty the bag ever so often. If the same amount of work is collected from each, wouldn't the ( bags-buckets ) need to be emptied just as often. What am I missing? Other than adding the cost of the cyclone separator, the bucket and all to other expense of making the change over.

The exhaust is then sent to a big pleated filter and the fine dust is dropped into a bucket. The argument is, it can capture finer partials ( hazardous to your health ) and improves air flow. But when the filter fills up it reduced airflow. When my shop vac, which has a pleated filter fills up with fine dust I loose suctions. And I have to clean the filter.  please read the rest before jumping in.

The bag on my dust collector is maybe 5 micron but as the holes in the bag are filled up it becomes a finer filter, where is the trade of or what is the difference? Next , Yes I do have to hit the bag loosen the particles ang get them to drop into the bag. but the pelted filter can also fill up and need to be cleaned. Where or what is the trade off? The dust drops down into my plastic bag or it drops into a bucket. So the only difference I see is the added expense of a pelted filter, added parts needed and a bucket and the time spent installing it.

Some dust collectors have the pelted filter and an arm that will help keep the filter clean. It is a great upgrade from what I have, but I do not see that feature on the other up grades. 

Before you jump all over me. Fact, no one will ever be able to collect all the dust, fine or not so fine, produced in the shop. An air cleaner really has a place when it come to fine airborne dust. I consider it a different problem it should be address in a different post altogether.

I have a trash can separator hooked to my two planners. It is by the planners and the dust collector in in the basement. It is easier to empty the can than it is to go up and down the stairs dragging the chips up the stairs. And the 20 trash can separator works just fine for the purpose. 

Tom

Whether I empty to barrel or the plastic bag the process is the same. Whether or not I shake out my upper bag or clean a pelted filter. it still should be done when the large partials are removed. All I see is a lot of added expense, with out much, if any, gain.

Or am I missing anything?

Tom

[tablesawtom]

A small cyclone separator is a good addition to a shop vac hooked up to a router table. There are more chips than dust created on a router table and it will save on filter cleanings. Application. Application, Application. One size does not fit all.

Tom

[jteneyck]

A properly sized cyclone will spin out not only large particles, but also almost all the fine dust, too.  Then only the very fine particles are passed on to the filter, so the filter works longer before the static pressure builds up and requires cleaning to do its job properly again.  

Cyclones are used in industry to separate particles into different sizes.  It's no different with wood dust.  DC manufacturers try to balance cyclone efficiency with flow requirements and the power required to obtain that flow.  Everything is a compromise, but the folks who offer well engineered systems, provide a system that gives good separation performance with pretty long cycles before the filter requires cleaning/replacement.  

I ditched filters long ago.  I use a cyclone to remove everything but the very fine particles and then exhaust them outside.  The performance never drops off because there is no filter to eventually clog up.  I live near Niagara Falls where it is cold many months of the year, but the temperature in my basement shop never drops more than a degree or two even if I run the DC for an hour at a time.  

I use a Fein dust extractor with a HEPA filter with my CNC.  I have a Dust Deputy cyclone before the Fein.  It removes all the chips and most of the fines, so I only have to change the bag in the Fein a few times per year.  The HEPA filter hasn't blinded yet in over a year of use.  

Forget YouTube separators and buy a cyclone designed for your DC needs.  

John

[tablesawtom]

Yes cyclone separators are used in industry, but we are not talking about industry but home shops. I checked Grizzly and their cheapest cyclone was slightly over $ 1,000 for a 1 1/2HP separator.  I found a Wen ( regular top and bottom bag) for a little over $300 and I Know Harbor Freight is cheaper. What do you consider properly sized for the average home shop. Even if a cyclone filters out the particles it still needs to be emptied. Volume of chips is volume of chips. If you don't do a lot of producing chips then it needs to be emptied less often but when it needs emptied, it needs to be emptied. And whether it is a canister type or a bag for the dust, both need cleaned. So we are back to value. And if I had Grizzly's cyclone dust collector then I wouldn't need to upgrade my system   

Again is the cost of doing all the upgrading to your system worth it? If we  are talking about a mini portable dust collector for $125 then a I would put a cyclone in front of the impeller to make it easier on me to not have to empty the bag as often. But in doing so I fast approach the cost of a better dust collector. And there is a lot of difference between a 525 CFM and a 1280 CFM unit. Again is the value there.

The  outside temperature this morning was 8 degrees and the high is expected to get to 18 degrees.  A vacuum can not exist in the natural world so if I pump air out of my shop at 1280 cubic feet per per minute I loose a lot of heat and what goes out must come in,  so I would also have 1280 cubic feet per minute of cold air coming in. Somehow I drought the exchange would be in my wallets best interest interest. Here we make certain that the door is completely closed when we enter or leave.

A lot of people do not have the means to just buy what they need. If you do then you are very fortunate. One day a person is living in a $5,000,000 home and today he has the cloths on his back.

[GaryMc]

I'm sure there are some on here that remember the "Thien baffle" that was all the rage several years ago - Google it.  Many articles on how to install within a DC or a "poor man's" cyclone dust separator. More years ago than I want to admit I built one into a 2hp Penn State Industries DC with big lower plastic bag and upper pleated filter (with cleaner paddles).  Almost all the chips fall into the bag along with some of the finer particles.  With the DC off, swiping the filter with the paddles or just banging on it causes most of the trapped dust to fall onto the baffle.  Then on startup most of that gets "cycloned" into the lower bag.  Still works well after - what, almost 20 years for this hobbyist.  Still need to empty the bag maybe twice a year but small price to pay.  And yes, I have a Jet cleaner circulating air in the shop to clean up any traces of really fine dust in the space.

Gary

[jteneyck]

If you use any kind of dust collector you need to empty the bin or bag or both, no getting around it. If you don't want to empty those things then don't use a DC or blow it all outside.  

As I said before, I blow over 1200 cfm outside. I have a window open across the shop for makeup air.  Temps in the Winter often go down to 20F, sometimes down to zero.  There is so much mass in the concrete walls and floor of my basement shop, plus everything in it, that the temperature just doesn't change much, a couple of degrees at the most.  You may choose to not believe that; it doesn't change the facts.  

There is no better dust collection system for continuous use than one with a cyclone.  Manufacturers have designed systems for most every situation, from single machine setups to central systems.  You asked what properly sized means for a home shop.  There's no universal answer.  It depends upon what machine or machines you want to collect dust from.  There is information readily available for how many CFM you need for most types of machines and how much static pressure drop there is for dust collector duct work, fittings, hose, etc.  Online calculators will walk you through how to determine the size system you need based on your needs.  Some DC companies will take your input and design a system for you. 

In the end, if you want improved dust collection, less filter cleaning, healthier air, whatever the objective, you have to spend some time and probably money.  In my case, I built a static pressure gage and measured the pressure drop at every location to determine why my old DC couldn't keep up with my new bandsaw.  Those data showed me I had too much pressure loss between my cyclone and DC fan, the filter bags, and in some of my ductwork.  Those low micron bags I had installed a couple of years earlier cut the CFM by almost half.  I ended up re-engineering my system by putting the DC fan directly on top of the outlet of the cyclone, and by eliminating the bags and blowing the air out a window.  Those changes gave me enough CFM that the DC now has no trouble taking care of all the dust my big bandsaw spits out when slicing wide veneer.  It ain't pretty, but it works very well.  

I started with something like this:



And this is how it looks now.  I got the cyclone for free off an old industrial vacuum cleaner system.  



Besides the shavings and sawdust from my planer and saws, this shows you how much fine stuff the cyclone removes when running my drum sander.  



Not much goes outside. 

John

[tablesawtom]

Have you looked at any of the videos' to see what I am talking about? probably not.
Tom

[jteneyck]

Have you looked at any of the videos' to see what I am talking about? probably not.
Tom

I would if you posted links.  But really, what's your point with your post?  If you think there's no gain by adding a baffle, cyclone, whatever, because you still have to dispose of the same amount of material but now split into more than one bucket or bag, that's your prerogative.  

The responses you got from your post over at SMC are pretty consistent with what has been said here.  

John

[fixtureman]

I have a Thien separator on my HP dust collector.  I get very little fine dust in the bag as most are in the Thien barrel

[fixtureman]

I would if you posted links.  But really, what's your point with your post?  If you think there's no gain by adding a baffle, cyclone, whatever, because you still have to dispose of the same amount of material but now split into more than one bucket or bag, that's your prerogative.  

The responses you got from your post over at SMC are pretty consistent with what has been said here.  

John

Yes I still have to empty my barrel but it is easier then reattaching the bag