dust/chip collection

[John Piwaron]

I was reviewing some of what Bill Pentz has written on his website. It occurs to me that this could become very involved. And there's his apparent recommendation for using 6" tubing to connect tools to the dust collector.

It's overwhelming.

What are you using? Have many people gone the whole "Bill Pentz route" or something less than that?

What are *you* doing?

I can say that right now, I'm at the point of deciding which dust collector to try shoehorning into my micro sized shop. I actually use a shop vac with a cleanstream filter as the collection device for my planer and soon my TS. That's about it at the moment. There's more to come, but I want a sense of how far to take this. I'm a hobby woodworker building maybe 2 or 3 serious projects in a year.

[Al Willits]

John, no expert but it seems to be a rags or riches kinda deal.
Those with both the funds and room seem to go for the major DC systems and those who have less room or money go for something else.

If your like me and don't have the room to put a full blown DC system in your shop/garage/whatever, you might consider one of the portable units, I have the JDS Dust Force which works well for me, and its on wheels so I can move it around if needed, I'm also running the 4" ducts and they seem to work fine.

Most here go by the bigger is better theory, and that's fine I guess if you have the room, kinda hard though for some of us.

Good luck with your choice, it can be confusing.

Al

[Don Baer]

A shop vac won't work very well. Presently I use the 2 HP 1200 CFM from harbor freight. It costs less then $200 and does a great job of chip collection. When I build my perm shop I'll go with the pentz design.

[Jim Becker]

My main run starts at 7" (which is determined by my particular cyclone, an Onieda) and generally is 6" from the first major branch until it steps to 5" near the end. Drops are 6", 5" or 4", depending on the tool and location on the system. Your duct work needs to be matched to your dust collection system's requirements and capacities.

[Art Mulder]

It's overwhelming.

Yup, it is. People can argue passionately about it, and it is hard to argue with them about safety. (Ditto for the Sawstop, by the way)

Sounds like you have a small shop though. I work out of a basement shop and I settled on a 2HP single stage import DC. It has a decent sized fan on it. And I bought a good quality 1 micron bag for it. And I run a 4" PVC pipe about 15' down the side of my shop, and have some 4" flex hose to my major tools. I might convert to a 6" main at some point, but 6" PVC is not easy to come by.

I'm pretty satisfied at the job it does of keeping the dust out of the air.

[Matt Moore]

WARNING... WARNING.... THIS MESSAGE WILL SELF DESTRUCT IN 10 SECONDS.....

Now seriously, this can be a heated topic.

A key point that you made is that you only do 2 to 3 serious projects per year. If you do that and you are doing this in a open garage setting, then the impact of the dust is not nearly as much as a completely closed in basement shop.

There are so many variables to the issue and it can get really complicated. Most people will have some sort of dust collection and maybe an air filter and lust after something larger/better. Some are able to justify the larger/bigger solution due to either the availabiliy of funds or the amount of time they spend making dust or maybe both.

I think the biggest point is to take the dust seriously but realize you are not in your shop 40 hours a week. If I were in there that much I would definately have a full fledged system like BP recommends.

[glenn bradley]

I'd love a cyclone but in my "real" world of hobbyist woodworking I get by on a $200 Delta "chip" collector with a trash can seperator. I only task it with one machine at a time and take great caution to get the most out of my ducting that I can. The seperator puts a helluva hit on the CFM but (here comes the lazy part) I can empty the trash can a half dozen times or more before I have to clean out the DC bags.

I'm in SoCal and can work with the Garage, er . . Shop doors open almost year round so it stays pretty clear in there. In the DC world I 'strive for perfection but settle for realistic'. By that I mean realistic for me and my cash flow. Your health is well worth the investment if your working environment calls for it. Just MHO.

[Jeffrey Makiel]

This subject need not be 'overwhelming'. However, I can see your point.

One doesn't need to be an automotive designer and mechanic to drive a car. So why does one need to be a HVAC engineer and industrial hygenist to add a dust collection system for the home hobby woodshop?

If you are on a budget, as with many folks that do woodworking as a hobby, a single stage 2hp dust collector with quality bags and 6" dia duct (PVC or metal) is the simple choice. Add some simple blast gates, 4" duct branches for small machines and flex duct. Also, make some box hoods for tools that need them like miter saws or radial arm saws.

If you want added convenience and ease of maintenance, consider a remote on/off switch, or a two stage cyclone, or perhaps even electrically activated blast gates. But I view these as conveniences that can only be judged necessary by the individual's time spent in the shop, budget, and willingness to do maintenance. The only caveat I can think of are hobbyists that have drum sanders which demand a two stage system.

Just my opinion...and I've been wrong before!
-Jeff :)

[Christopher Kochan]

My personal approach is to use a 2hp dust collector for chip collection and helping keep my shop (garage) clean, an air cleaner to help catch little stuff that stays floating in the "shop" after I'm done, a box fan to help flush dust out of the garage while I'm working (I try to keep the door open), and a good 3m half-face respirator.

The respirator is what protects my lungs, and to be honest, even with a killer dust collection system with 5hp, 7" ducts, and my equipment modified to the max, I still don't believe I would be able to effectively catch dust with my miter saw, handheld sanders, or free hand sanding to the point where I would NOT need to wear a respirator.

Therefore I do the best I can to keep the garage clean, clean freeborn particles during and especially after I leave the shop (so it's reasonably clean the next day when I come in), and wear a respirator to do the important work (which I would wear regardless).

Effective for a good portion of the dust, and doesn't break the bank. Perfect? Not by a long shot, but I do the best I can.

Oh, and take a shower after a long day in the shop. It'll wash all the stuff that's settled on you while your working, rather than stirring it up later.

My itsy-bitsy 2 cents worth.

Best,
Christopher

[Lou Ferrarini]

John,

I, like you, were using a shop vac on my planer and quickly came to the conclusion that it was crazy trying to empty that thing 3 times a day. The planer will fill it quickly.

My solution was to go with the Jet DCK1100 (with cannister filter - highly recommended) which I piped to my tools with 4" PVC S&D pipe. It does a good job if I only open one gate at a time. If you are starting from scratch, I highly recommend you use the 6" pipe if you can get it.

Also, Don't forget an air cleaner. It will remove the small particles from the air that will usually end up in your lungs. I use the Delta, it hangs from the celing out of the way, is remote controlled and has a washable filter.

[Ted Miller]

John, Yes it will make you crazy, I have few good freinds who are "old wood guys" and we usually sit around and talk about who has the biggest jointer or what dust collection is the best, since these guys have been chipping wood for 30-40 years they have some lung problems so we discuss this topic often. Bill Pentz is with out a doubt the master when it comes to "air safety" due to his lung issues, I have learned alot from him and I noticed switching over to his ideas and I even breath better when chipping wood, yes it was not cheap to fit my small garage/shop but I do sleep better at night, I also went one step further and I vent outside, so no returning air has to be filtered to return to my work area...

[John Piwaron]

John,

Also, Don't forget an air cleaner. It will remove the small particles from the air that will usually end up in your lungs. I use the Delta, it hangs from the celing out of the way, is remote controlled and has a washable filter.

That's what I forgot to add to my original posting - the air cleaner. I do have one of them. Not the big rectangular kind most people seem to get, the smaller triangular shaped one from Delta, the AP100. The big ones simply won't fit in my space. I set it up on a timer. It runs while I'm in there and continues after I leave, shutting itself off.

[Robert Mickley]

I'm poor so mines cobbled together :D I do have JDS dust force which I got at an auction for $60. Scrounged some tin from a nephew and built a cyclone based on BP's plans. Ran 4 inch duct work since that was what was able to scrounge together.

It's changed some since this was taken. The bag holder is now down further, bag is on top and I have a clear plastic bag on the bottom to collect anything that gets past the cyclone. I think I messed up my air ramp since some dust does get by but it works fairly well.

Keep in mind I'm no metal worker so its kind of ugly but it gets the job done.
http://www.sawmillcreek.org/attachment.php?attachmentid=47922&d=1159900525

I'm working up a design for a filter satck with a shaker to clean the filters with every night, then the bag goes away completely

(http://www.sawmillcreek.org/attachment.php?attachmentid=47922&d=1159900525)

[JayStPeter]

I started with a shop vac, then got a Jet DC1100, and now a big cyclone. Over the years I've increased the size of my shop and the amount of dust created. I have also been willing to spend some cash to avoid the blowing of brown boogers. That includes the DC and some Festool products for handheld use. There are plenty of hidden expenses to getting all your equipment collecting dust reasonably. To me, having to wear a mask and/or having everything covered in fine dust makes the hobby less enjoyable. I have had to put off getting other tools to improve the dust collection capabilities first. Gotta make choices with the yearly shop budget. My tool funds are allocated based on keeping the hobby enjoyable and improving my productivity during the too little shop time I get.

[Bill Pentz]

I was reviewing some of what Bill Pentz has written on his website. It occurs to me that this could become very involved. And there's his apparent recommendation for using 6" tubing to connect tools to the dust collector.

It's overwhelming.

What are you using? Have many people gone the whole "Bill Pentz route" or something less than that?

What are *you* doing?

I can say that right now, I'm at the point of deciding which dust collector to try shoehorning into my micro sized shop. I actually use a shop vac with a cleanstream filter as the collection device for my planer and soon my TS. That's about it at the moment. There's more to come, but I want a sense of how far to take this. I'm a hobby woodworker building maybe 2 or 3 serious projects in a year.

John,

We each need to look at the risks and then decide what level of dust collection is ample. Based on my personal experiences I believe most small shop woodworkers leave dust collection as one of our last priorities when protecting ourselves from fine wood dust should be one of our first. Based on my reading and study, the medical research is clear there is no safe level of wood dust exposure. Every wood dust exposure causes some measurable loss of respiratory function and exposure over time creates permanent damage and increases risk of cancer. We know that some woods are fairly toxic and some cause us to build up allergic reactions fairly quickly. I personally have a large pile of some of the nicest tools that money can buy sitting in a pile unused for the last seven years because of my own reactions. I also can tell you that finding yourself exhausted and broken out in a heavy sweat like I was yesterday from less than five minutes of wall painting is not a fun way to live. We know that over time most full time woodworkers who work in large commercial facilities protected by regular government air quality regulation and testing develop long term wood dust related medical problems, some serious like mine. That is why ACGIH came out with their five times tougher standard and later the European Union came out with their now fifty times tougher standards. I think all woodworkers should work outside with a good dust mask and jumper that they remove before returning into their homes, or they should build for themselves a good dust collection solution.

I wish installing a good fine dust collection was easier, but the reality is today you need to either spend big bucks to buy a professional system guaranteed to meet government standards, build your own, or go without. Building your own is not that hard, but does take some study and work because almost all you can buy off the shelf are “chip collection” solutions that do a great job of collecting the sawdust and chips we would otherwise sweep up with a broom. To build your own you need a multi pronged approach. I strongly recommend buying or building a good downdraft table. Likewise I think most smaller tools require us to buy a far better shop vacuum than most traditional units. Most need a heavy commercial grade unit like the big Fein 18 gallon stainless steel vacuum (or Festool or real commercial) shop vacuum that pulls a real 90” or greater pressure and will take a HEPA filter (add a Sears red-line HEPA for the Fein). We need a strong shop vacuum for our tools with smaller ports. Next you need to follow the guidelines laid out by the professional dust collection firms that provide and install the dust collection equipment used to meet government air quality standards.

These professional air engineers long ago learned that, fine airborne dust spreads so quickly that to pass the anticipated OSHA air quality regulations the fine dust must be collected at the source as it is made before it can spread then that dust needs eliminated. These firms shared what they found works for good fine dust collection and most of it applies to small shops because our larger tools are mostly identical to smaller large shop tools. What they learned for small shops is the cost to replace existing tools is mostly cost prohibitive, so the only way to get good fine dust collection at most of these older tools designs is by upgrading to hoods that contain, control, and deliver the fine dust for collection. They shared that most larger tools need about 800 CFM airflow to amply collect the dust to meet OSHA standards. That airflow climbs to about 25% more to meet the higher medical air quality standards now already adopted in the European Union. In short it takes double to triple the airflow for good fine dust collection as it does to just collect the chips unless tools are built from the ground up to totally contain the dust as it is produced. The magazine testing shows most 1.5 and 2 hp dust collectors only move ample air when wheeled between tools with minimal ducting. For shops with a full set of ducting we really need at least a 3 hp dust collector. I personally use a 1.5 hp Jet DC in that role which has been upgraded with a fine filter and 6" smooth walled flex. Because cyclones add about a third more overhead to force the air into a tight separation spiral the magazine testing results show we mostly need a bigger than 3 hp cyclone to move the needed air in shops with ducting. Because air at typical dust collection pressures is more like water and barely compresses at all, any small port, duct, hose, roughness, or sharp bends will severely limit airflow similar to closing a water valve. Their tables show that all 6” duct for the 800 CFM systems is appropriate and 7” is needed for the 1000 CFM systems unless we want to step up to oversized motors and blowers that generate higher than normal pressures. They found getting rid of the fine dust requires separating off the larger chips and sawdust, and then either venting the remaining fine dust outside or returning the air after filtering through fine filters. Because of the high airflows and dust levels typical with woodworking operations they found that in all but the most extreme climates it most cost effective to use a cyclone to separate off the heavier sawdust and chips then blow the fine dust away outside. That let them continue to use existing cyclones and dust collectors already designed to freely pass the 30-micron and smaller particles. In instances where climate or local requirements required filtering the air, they developed and recommended staged separation and filtering systems that took the fine dust laden air normally exhausted outside then cleaned it using fine filters effective down to about 2-micron sized particles.

Sounds easy, but it is work, painful to change your tools, takes time and is often expensive. I think it is worth it which is why I have spent so much time sharing on my web pages.

bill

[Ted Miller]

Bill, Thank you for the post, I know after I installed the Clear Vue and jointing 100s of bf in a row I can not even smell the dust in my shop, now I do vent outside and I wish I would have found your site earlier in my woodworking years, but I guess better late than never. I look at it like this, I only do things 110%, I buy the best tools I can buy, so why not have the best air I can breath while I am working, I know living in Southern California had its advantages not having to worry about losing hot and cold air from my shop when the cyclone comes on, so venting outside is not a problem, but I do feel better about how I treat my lungs now than I did years ago, thanks again for your knowledge...

[Bob Dodge]

It's overwhelming.

What are you using?
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John,

Dust collection can basically be divided into two components; 1. The amount of air you want to move at your machines, and 2. The filtration stage.

If you're comfortable moving your dc close to your machines, you won't have to worry about a duct-network, so there's really no point in going there. However, if you do want to place your dc in a fixed location, then you'll have to take a closer look at optimizing your duct-runs. Basically, all that entails, is adequate velocity (through proper sizing).

The filtration stage is pretty well self-explanatory. Ideally, you'd want properly sized filters (for low pressure-drop) and an easy to maintain, well-manufactured filter (tight-fitting/no leaks/triple-stitched seams), and, efficiency in small particle capture. With many consumer-model dc's, a filter-upgrade is almost mandatory, however, some manufacturers/re-sellers such as Delta, and some of the General International, provide reasonably high-quality filters as "standard issue". You'll see many claiming to be "1 micron filters", but don't let the ratings fool you. There simply are no "mandatory testing standards" for consumer-model dc's. I'd highly recommend that you consider 16 oz needle-felt filtration.

Quality electricals may be a concern to heavy-users, as well as waste-capacity. Small capacity dc's means you'll have to shut-down more frequently to empty the dc. While these features can be desirable, it's up to you to decide whether or not you want to spend the extra money.

Let's look at the air-requirements of each of your machines. Many hobbyist shops will have a 10" table-saw, a planer, a jointer, possibly a bandsaw and a router-table.The table-saw will have one of the highest air-requirements. Buy a dc that can handle that saw, and you should have enough power to handle the others.

Ideally, you'd want two-point collection at the saw; one duct to the base, and another hooked-up to an overarm blade-cover (OA-BC). The OA-BC will dramatically reduce airborne waste (fines), especially if you work with "dirty" materials like MDF, Melamine, and particle-board. At the saw's base, a 4" hook-up should be more than adequate if it's properly set-up. If your dc is placed close to that saw, a well-designed 1 1/2 HP dc like the Delta 50-760 (11.5" impeller) will easily address that requirement. It would also run on 110v or 220v. For general hobbyist use, you won't find a better "standard equipment" filter. No upgrade required. Approximately $300. This was Fine-WoodWorking Magazine's "top pick" in the 1 1/2 HP category.

http://www.deltamachinery.com/index.asp?e=136&p=5815

If you do decide to run a duct-network, that 1 1/2 HP Delta should be placed reasonably close to the saw, and then run a properly "sized" duct to your other machines. If the dc will be placed "at a distance", in a "convenient location", well, I'd recommend that you consider a slightly more powerful dc.(2 HP/ 12" impeller / 6"+ porting / twin filters) A dc like the 2 HP Delta 50-761 will give you all of those features, with double waste-capacity, and 7" porting; along with twin over-sized filters (41 sq.ft.) Roughly $500.

http://www.deltamachinery.com/index.asp?e=136&p=5816

Beyond that price-point, you're starting to look at small industrial 2 HP sinlge-stages with heavy-duty Baldor motor, and twin 16 oz. needle-felt filtration, like the Pyradia/Belfab "J.J.". This dc has an ultra-small foot-print (21" x 21"), and is just under 7 feet tall. All 12 gauge steel construction, and built like a tank. High quality bearings, and balanced 12.5" non-sparking aluminum impeller. I use one of these im my shop, and it's an excellent performer. Pulls roughly 1100 ACFM at just under 5" SP. Availability can be quite limited depending on your location.

http://www.belfab.net/jj.html

In this same price-range, you might also want to consider one of the better-designed 2 HP cyclones. You'll lose mobility, and waste capacity can be a little small unless you have the ceiling-height to mount them higher with a larger-capacity drum. If not, you could always add a secondary pre-separator near those machines that produce the most waste. (planer/jointer). That market is currently very competitive, with excellent value to be had.

Regardless of which price-point you jump in at, you want to focus due-attention to your duct-work. Even the most powerful dc's will be brought to their knees by improper ducting. This can be especially important with a marginal dc. Ideally, you want a free-flowing network, devoid of unneccessary twists and bends, and limited use of small-diameter flex-hose. A good dc system, is all about "proper balance".

Good luck,

Bob

[glenn bradley]

I'll second the air scrubber although some folks feel they stir up more dust than they catch. I'm happy with my shopmade version. 1100 CFM gable fan on sale at the BORG, $35, filters on clearance at the BORG $1 each, scrap wood from the neighbor tearing down an old shed $0.

[John Piwaron]

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Ideally, you'd want two-point collection at the saw; one duct to the base, and another hooked-up to an overarm blade-cover (OA-BC). The OA-BC will dramatically reduce airborne waste (fines), especially if you work with "dirty" materials like MDF, Melamine, and particle-board.
Good luck,

Bob


Who makes overarm blade covers? That sounds good. The information on dust collectors is good too.

Bill's posting in this thread is usefull too. I want to acknowledge his contribution.

For me, money is an issue at this time, but only in light of my very recent TS upgrade. Upgraded for the purpose of being able to collect dust. That and an air cleaner were bought at the same time. Now I have to digest that. And while I'm digesting, I'll use the information every has (or will) contributed in defining my own course of action for my next move in the area of collecting the mess. My shop, er, "studio" :) is in my basement. I live in Milwaukee, so venting outside isn't gonna happen. I can't blow heated air outside. And my A/C barely keeps up in summer, so not then either, thought I must say, when summers here, the tools are mostly silent.

So in the hopefully before too long, I can implement better dust collection than the shop vac can do.

BTW, when I looked, the clear vue stuff looked good and wasn't priced all that unreasonably.

[Matt Moore]

There a number solutions for a overarm dust collecting guard.

Many are please with the shark guard.
http://www.leestyron.com/sharkguard.php

Many have something like the Penn State guard. There are several brands that are similar to this. I only put this one here since it is the first one I thought of and knew where to get the link.
http://www.pennstateind.com/store/tsguard.html

[Bob Dodge]

John,

If you're going to add an overarm blade-cover. I'd seriously consider the Excalibur. Not only is it well built, put it also has the best dust-collection. "General" now owns Excalibur. Any General, or General International dealer will carry that item.

There are also plenty of fine shop-built overarm guards I've seen posted by the members here.

Here's a discussion about OA-BC's that appeared elsewhere.


Question
I'm thinking of getting an overarm blade cover to help with dust in the shop. I've looked at Excalibur, Exactor and one offered by Penn State. Does anyone have feedback on these? Are there other ones I should consider? Are there other ways to deal with dust off the table saw that would work better? Any suggestions would be appreciated
Forum Responses
(Dust Collection, Safety and Plant Operation Forum)
From contributor R:
I have two of the Excaliburs and one Exactor mounted on cabinet saws. They are in use daily, so I guess I can give you an honest opinion of these two particular brands.
Excalibur - Good to excellent dust collection, difficult to remove from saw in the event that you need clearance to mill large parts. Very nicely designed dust hood, which is easily manipulated to provide optimum safety and dust collection.
Exactor - poor dust collection. I bought this model because of price ($249 three years ago) and while I do not totally regret the purchase, I have not been very impressed. They advertise as having a 3" dust collection boom, but in reality it is much less because the boom reduces from 3" to 2 1/2" and then even further down to 2" at the dust collection hood. On the plus side, the boom does swing completely out of the way for milling large parts, but I have to say this is the only plus. The dust collection hood is very difficult to adjust and is somewhat flimsy, where the Excalibur's is solid. But here is the final proof of which is better... On any given day doing equal tasks on PM66 saws hooked up to identical 3HP dust collectors, the Excalibur will pick up one full dust collector bag and in that same amount of time, the Exactor will have only picked up about 1/8th of a bag.

[Bill Pentz]

...Bill's posting in this thread is usefull too. I want to acknowledge his contribution.

For me, money is an issue at this time, but only in light of my very recent TS upgrade. Upgraded for the purpose of being able to collect dust. That and an air cleaner were bought at the same time. Now I have to digest that. And while I'm digesting, I'll use the information every has (or will) contributed in defining my own course of action for my next move in the area of collecting the mess. My shop, er, "studio" :) is in my basement. I live in Milwaukee, so venting outside isn't gonna happen. I can't blow heated air outside. And my A/C barely keeps up in summer, so not then either, thought I must say, when summers here, the tools are mostly silent....
John,

Thank you for the kind words.

In terms of your shop, if you don’t want to or cannot exhaust the air outside, then you are going to need to decide on what level of dust collection safety you want then get or make a dust collector or cyclone that will move ample air, fix your tool hoods and ports, move a portable DC between machines or put in large enough ducting, and then use a separator filter combination that will ensure you have good dust collection.

My goal with my web pages is to help others avoid the mess I found when I decided to clean up my shop air quality. When I started in 1999 there was nothing but controversy on just about every dust collection topic. Figuring out if fine dust is bad for us and how much before it becomes a problem was a mess with some experts saying no problem and others saying death would soon follow a fine dust exposure. There is no industry standard for small shops and at least five standards for commercial shops depending upon size and location, yet little has changed since. Small shop vendors still have no standards to meet so build anything they can sell. The next level up for shops subject to regular fire marshal inspections sell good “chip collectors" that do a good job collecting the same sawdust and chips we would otherwise sweep up with a broom. Then we got into equipment and dust collection installations that consistently meet OSHA standards. With too many getting ill at OSHA exposure levels ACGIH came out with a five times tougher air quality standard, so some equipment is built to meet that recommendation. With the announcement that some wood dusts are cancer causing agents, we also have firms that build dust collection equipment that will comply with the fifty times tougher medical recommendations that are now the European Union standard. Each still provides very different advice based on what they sell. We still have serious problems with vendor advertised performance at maximums instead of working levels for airflow and filtering. Most vendors still recommend graduated sized ducting solutions that work poorly for small one machine at a time shops. Likewise, the filter situation remains deplorable where what you get may or may not provide any real protection. Add the fact that most small shop tools still come with undersized ports and hoods that are pretty much useless for good fine dust collection and I fully agree with you that picking out a good small shop dust collection system is a pain.

After finding the equipment situation deplorable, especially the cyclones, I rolled up my sleeves and used my over thirty years of engineering experience to build my own cyclone and blower. It worked and my doctor pushed me into sharing. I shared with some Internet articles, got buried in questions, and in self defense moved those articles and answers to frequently asked questions to my personal web pages. The more I shared the more people wanted. The result soon overwhelmed my small local server so I had to upgrade to a commercial server able to handle the 3 million plus hits a day along with a unique visitor count that went over 18,000. Now seven years later I still get about 16,000 unique visitors a day and in spite of asking people to limit their emails rarely get by with less than four to six hours of email a day.

(edited by John Bailey)

bill



----------------------------------

John,

Dust collection can basically be divided into two components; 1. The amount of air you want to move at your machines, and 2. The filtration stage. This is exactly true for “chip collection”, but for good fine dust collection there is far more involved. My personal testing found that if you do not start with fixing your tools with hoods that amply contain, control, and direct the fine dust for collection there is zero chance of building a viable fine dust collection system. Even the big 5 hp Oneida-Air and 5 hp Pentz designed cyclones I tested with “ideal” ducting, airflow, and filtering had airborne dust levels that failed badly with more than double the OSHA maximums after just five minutes (54 linear feet) up wood cutting.

If you're comfortable moving your dc close to your machines, you won't have to worry about a duct-network, so there's really no point in going there. However, if you do want to place your dc in a fixed location, then you'll have to take a closer look at optimizing your duct-runs. Basically, all that entails, is adequate velocity (through proper sizing). Again ample velocity will gather the chips, but you also need ample volume to cover the surface area needed to also capture the fine dust. Layout, ducting material, minimizing run length, and having smooth clean runs with long radius bends is very important to keep the airflow we need for our minimal sized blowers to provide good fine dust collection. One of my friends who uses a 5 hp cyclone of mine that we built together started off with a nice looking all 6” HVAC ducting system, but he chose to use some harsh T and 90 degree bends. That cut his total airflow by almost a third below what we got after changing out some of his duct fittings..

The filtration stage is pretty well self-explanatory. Ideally, you'd want properly sized filters (for low pressure-drop) and an easy to maintain, well-manufactured filter (tight-fitting/no leaks/triple-stitched seams), and, efficiency in small particle capture. With many consumer-model dc's, a filter-upgrade is almost mandatory, however, some manufacturers/re-sellers such as Delta, and some of the General International, provide reasonably high-quality filters as "standard issue". You'll see many claiming to be "1 micron filters", but don't let the ratings fool you. There simply are no "mandatory testing standards" for consumer-model dc's. I'd highly recommend that you consider 16 oz needle-felt filtration. The experts say we need 1 to 2-micron filtration for good OSHA level fine dust collection and only 30-micron filters for good “chip collection”. A standard sized top filter bag that is about 20 square feet in area is more than ample filter area for a typical “chip collection” 30-micron filter to take care of an 800 CFM dust collector. The heavy 16 ounce felt rated at 1-micron when fully seasoned needs to be setup with at least one square foot of filter area for every 16 cubic feet of airflow according to Donaldson-Torit, one of the premiere suppliers of commercial dust collection systems for customers subject to regular OSHA air quality inspections. For the 800 to 1000 CFM airflows needed to meet OSHA or higher medical air quality standards this calls for a filter bag that is 40 to 50 square feet in area. A big filter bag today is one that has a 20” diameter and stands 4’ tall. That gives a top and side area of under 25 square feet. A typical fine dust collector bag is half that size. If you dig deeper, you will find in the Donaldson Torit and other filter material application notes that they actually recommend using at least double that minimum area. Doing so quadruples filter life and quadruples time between cleanings. Most that use these bags eventually tire of their turning hard like plaster and always being a messy pain that leaves us covered in dust during cleaning. Moreover, as these bags age, they tend to build very high resistance. My aftermarket fine filter bag developed such a thick cake of dust that it added over 4.5” of resistance. That was enough to all but smother the airflow from my good quality 1.5 hp dust collector. I strongly recommend either putting the dust collectors outside with a standard 30-micron bag or instead doing your homework and get ample bag area.

Quality electricals may be a concern to heavy-users, as well as waste-capacity. Small capacity dc's means you'll have to shut-down more frequently to empty the dc. While these features can be desirable, it's up to you to decide whether or not you want to spend the extra money.

Let's look at the air-requirements of each of your machines. Many hobbyist shops will have a 10" table-saw, a planer, a jointer, possibly a bandsaw and a router-table.The table-saw will have one of the highest air-requirements. Buy a dc that can handle that saw, and you should have enough power to handle the others. The table saw “chip collection” requirement is 350 CFM with only collection below the blade. For OSHA level collection the recommendation is 440 CFM below the blade plus use of a good blade guard with another 350 CFM for a total of 790 CFM at a typical 10” table saw. Add about 25% more CFM to get the collection needed for the higher standard. This is the easy part. Unlike commercial industrial blower technology which is mature meaning you get near identical performance from identical sized blowers from almost every vendor, the small shop blowers are all over the map making picking a properly sized blower difficult. The small shop tool marketplace is intensely competitive with low cost import tool vendors who have a long history of exaggerating their tool performances, especially for dust collectors and cyclones. Based on Fine Woodworking Magazine testing you might get by with a 1.5 hp Delta or Jet, but by the time you add overhead for much ducting you will be hard pressed to have ample collection to meet OSHA air quality.

Ideally, you'd want two-point collection at the saw; one duct to the base, and another hooked-up to an overarm blade-cover (OA-BC). The OA-BC will dramatically reduce airborne waste (fines), especially if you work with "dirty" materials like MDF, Melamine, and particle-board. You only need lower collection for good “chip collection” and need the two point collection only if you are going after OSHA or better air quality. Although over arm blade covers with collection are nice, many get excellent dust collection with splitter mounted blade covers. The best of these arrangements I’ve seen uses a Biesemeyer anti kickback riving knife splitter with a Hammer/Felder blade guard hood connected to a larger shop vacuum. If you are not willing to pay the big bucks to get a vacuum with a real 90” or better draw, then you should consider using a 4” blade guard hoods. The new Shark Guard looks good, but I have not tried one. At the saw's base, a 4" hook-up should be more than adequate if it's properly set-up. A 4” connection attached to a typical small shop dust collector like the Delta 1.5 hp unit described will support about 350 CFM which is great for “chip collection”, but to get our needed 440 CFM for fine dust collection we really should use a 5” lower connection. This means also using a 6” down drop and at least 6” ducting main. The exception we already discussed and this is instead using a powerful vacuum on the blade guard instead of a dust collector connection. If your dc is placed close to that aw, a well-designed 1 1/2 HP dc like the Delta 50-760 (11.5" impeller) will easily address that requirement. It would also run on 110v or 220v. For general hobbyist use, you won't find a better "standard equipment" filter. No upgrade required. Approximately $300. This was Fine-WoodWorking Magazine's "top pick" in the 1 1/2 HP category. I worked out the impeller sizing that Delta followed to make this unit a top performer. I also consulted on the Fine Wood Working magazine testing done by Michael Standish, someone I regularly talk with. The reason he chose to use my recommended cartridge filter upgrade during his testing for that article is there is such a wide difference in filtering level and quality. He wanted a consistent good quality filter that did not severely impede airflow. Yes, the Delta and the Jet that rated so well on his tests are both excellent machines. I own the Jet myself. However, neither is ample to support more than minimal dust collection when wheeled between machines even when using a short length of 6” smooth walled flex hose. Use 4” hose and have a dirty filter and you suddenly have a machine that will give great “chip collection” but be short of the air needed for good collection. Almost all who buy these eventually upgrade to bigger units.

http://www.deltamachinery.com/index.asp?e=136&p=5815

If you do decide to run a duct-network, that 1 1/2 HP Delta should be placed reasonably close to the saw, and then run a properly "sized" duct to your other machines. If the dc will be placed "at a distance", in a "convenient location", well, I'd recommend that you consider a slightly more powerful dc.(2 HP/ 12" impeller / 6"+ porting / twin filters) A dc like the 2 HP Delta 50-761 will give you all of those features, with double waste-capacity, and 7" porting; along with twin over-sized filters (41 sq.ft.) Roughly $500. Many firms offer larger dust collectors ample to power the ducting in a small shop. If you go through the resistance calculation and add the overhead for dirty filters, you will find the 2 hp dust collectors exceed the airflow we need for good “chip collection” but fall short of the minimums needed for good fine dust collection. The many who buy then later upgrade from their 2 hp units shows this to be true. Additionally, emptying filter bags continues to be an ongoing concern.

http://www.deltamachinery.com/index.asp?e=136&p=5816

Beyond that price-point, you're starting to look at small industrial 2 HP sinlge-stages with heavy-duty Baldor motor, and twin 16 oz. needle-felt filtration, like the Pyradia/Belfab "J.J.". This dc has an ultra-small foot-print (21" x 21"), and is just under 7 feet tall. All 12 gauge steel construction, and built like a tank. High quality bearings, and balanced 12.5" non-sparking aluminum impeller. I use one of these im my shop, and it's an excellent performer. Pulls roughly 1100 ACFM at just under 5" SP. Availability can be quite limited depending on your location. Few small shop woodworkers use these dust collectors because of their $900 to $1200 price. Their airflows likewise have been shown on prior SMC posts to not stack up very well against comparable Delta and Jet units at half the cost.

http://www.belfab.net/jj.html

In this same price-range, you might also want to consider one of the better-designed 2 HP cyclones. You'll lose mobility, and waste capacity can be a little small unless you have the ceiling-height to mount them higher with a larger-capacity drum. If not, you could always add a secondary pre-separator near those machines that produce the most waste. (planer/jointer). That market is currently very competitive, with excellent value to be had. Take away the overhead to power the cyclonic action, remove the overhead to power the ducting, then add the overhead to power a dirty filter and most 2 hp cyclones again will do okay “chip collection” but end up challenged to provide the airflows needed for good fine dust collection. Unless you have really short ducting runs and a very efficient cyclone design 2 hp is just plain not big enough to move the airflow that over twenty years of air engineering shows we need for good fine dust collection at our larger tools.

Regardless of which price-point you jump in at, you want to focus due-attention to your duct-work. Even the most powerful dc's will be brought to their knees by improper ducting. This can be especially important with a marginal dc. Ideally, you want a free-flowing network, devoid of unneccessary twists and bends, and limited use of small-diameter flex-hose. A good dc system, is all about "proper balance".Although this sounds good and is good advice, I am confused about the specifics of how to accomplish this along with so much else being a mix of good fine dust collection and “chip collection”. That is why I took the time to build my web pages that succinctly define what it is I recommend collecting and all the steps needed to do that job. My web pages are not a one person effort but instead the culmination of many for many years sharing their advice and techniques, plus innumerable professionals helping to keep us on track. In short, I would recommend you take the trouble to study and follow the advice on those pages if you decided you want to have good fine dust collection in your shop.

Good luck,

Bob
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[Bob Dodge]

John,

Let's ask the question "How much is enough?"

Is it possible to have an overkill situation? Is it realistic to recommend to an occasional weekend warrior that he needs the same protection as a career woodworker who will have 20+ years of exposure on a daily basis? If I remember correctly, you have only a few machines, and do roughly "perhaps 3 serious projects per year". Let's examine if it makes sense to spend $2000. on a dust-collection system. (small cyclone with complete ducting system and high-end filtration)

Just what is "overkill"? Where do we draw the line? Let's start directly "at source".

A dust collector, is nothing more than a waste transport system, with a filtration stage. It doesn't matter what style of dc you have, it is solely the suction pressure that your dc generates, that will deal with your dust. This suction pressure, in conjunction with your ducting and hood resistance, will determine your airflow, both in volume (CFM), and velocity (static-pressure).

When you select the volume of air you want to move at a particular tool, you have to consider two aspects. One, is the ambient air-mass surrounding you, and the second is, the high-velocity at the entry of your hood. Naturally, if you hold your open hand 3 feet from the duct opening, you will feel no suction pressure. Air is moving far to slowly at that point. As you approach the duct-opening within a few inches, the air is moving much more rapidly at that point, and eventually, the suction will "slap" your hand against that duct opening. How does that apply to your dust-collection requirement? Well, let's look at that more closely.

If your hood is placed close to your cutter, and you have properly sized your dc and it's ducting, the rapidly moving air will ideally draw all of your waste into the pipe. Not "some of it", but "all of it". If you're not achieving that goal, then some of those waste particles may have enough "escape velocity" to saturate the ambient air-mass around your work position.

That fine waste is best dealt with by a certain amount of CFM. Naturally, the more CFM you have, the quicker that ambient air will be drawn back in to the dc's hood, reducing your direct exposure.

Now, is it possible to have increased your exposure even if you move more CFM? That answer is "YES". How so? Because you may have a large hood opening, that larger CFM amount, is entering the hood at a reduced velocity. If that entry-velocity is lower than the waste-particles' escape velocity, then you will still have exposure. In other words, if you flow 800 CFM through a 6" pipe or hood, that entry-velocity will be roughly 4076 FPM. (roughly 46 MPH). A 10" saw-blade, at 3450 rpm, has a tip-speed of roughly 103 MPH. Some of those rapidly moving particles may escape into your ambient air-mass. This is a very simplistic example, but, it illustrates the principle.

Now, if you flowed 800 CFM into a 7" hood, your velocity will drop even lower, to 34 MPH. If you flowed that same 800 CFM into a smaller pipe, then the entry velocity will be much higher. You'd still be moving the same volume of ambient air, but velocity into the hood itself would increase dramatically. For example, a 4" hood would have an entry velocity of 9172 FPM.(104.3 MPH). Naturally, you'd have to have a dc capable of pulling that required pressure in the first place. With a bell-mouth entry, that would require 5.46" SP at the hood.

Once that 800 CFM has entered the hood, you want to ensure that you have appropriate velocity in your pipe, to support the waste to it's final destinatiion. In a horizontal pipe, 3500 FPM is more than adequate to support any type of woodwaste. The ideal pipe to deal with that 800 CFM volume, is 6" pipe. At 800 CFM, your air-velocity will be 4076 FPM, which would be reasonable. If you chose a 7" pipe, your velocity would be too low for transporting all waste-types. You'd have a velocity of 2994 FPM, which would handle low-density waste, but be inadequate for heavier waste. You'd risk a gradual "settling out" and accumulation in your pipe.

If you tried to move that same 800 CFM through a smaller diameter 4" pipe, you'd have a velocity of 9172 FPM, which would give you an astronomical resistance. With 4" flex, a 30 foot hose will have 28.7" SP. The horsepower required to deal with that load would be 13.8 HP.You'd be operating at 5700 FPM over your requirement. By selecting a 6" diameter pipe, you'll have adequate velocity, and low demand from your dc's suction-pressure.

A 30 foot long smooth-walled pipe such as PVC, would have a resistance of only 1.1" SP. For that particular machine's scenario, you'd require a dc capable of pulling 800 CFM at 6.56" SP. (4" hood, and 30 ft. of 6" pipe) If this is your "worst-case scenario" machine, then anything beyond that is overkill. Wasted energy pure and simple. You could connect a 50 HP Torit-Donaldson cyclone to that machine, and you won't be any better off. Sure , the numbers would be amazing on their own merit, but, there is simply no benefit gained. In fact, it can be detrimental at the far end of the chain; your filtration stage.

With excess air flowing into the filter, your filter's efficiency will drop. A filter's efficiency is directly related to the interstitial velocity at that filter. That interstitial velocity is the speed at which air (and particles) flow through your filter. When you see a certified filter spec, it's not only about particle-size; it's also about particle velocity. For example, you may see a filter with certified 1 micron capture efficiency "AT" a certain velocity. Usually, that will be expressed as particle-size only, accompanied by a "letter", like "G" rating. Well, that "G" rating would be the velocity-spec. In otherwords, that filter will only effectively capture it's stated particle size, perhaps 99% of the time, at or below that given velocity. If the velocity spec is exceeded, that particle-size and capture percentage rating will not apply. Filters are not "brick-wall" for particle size. That's how you calculate the required filter.

This brings us back full-circle to your specific requirement. If your table-saw requires 800 CFM to deal with your ambient air, will a 1.5HP delta be adequate? Acccording to FWW Magazine's test earlier this year, that dc supposedly pulls 925 CFM at 3.5" SP as I recall, so yes, it will accomodate your requirement, as long as you choose the proper pipe-layout. If you try to "squeeze" that 925 CFM through too small a pipe, or too much length, then it simply won't do. With properly sized pipe, and an efficient layout, you'll do very well indeed. If you ask me if i believe those test results, well, no I don't. Mr. Standish who performed those tests, used a centerline velocity-pressure reading only, to calculate CFM. This is not uncommon among consumer-model dc's. Reduce that total CFM reading by roughly 10%, and that will be a more relistic airflow. Still, that same dc would have an airflow of roughly 835 ACFM at 3.5" SP. More than enough to deal with your saw.

Bob