Dust Collector Dilemma

[Marc Prudhomme]

Bill,
Just remember that if your machines do not have a 4'" dust port then you will have to modify them or you wont get the full cfm rating on all that money you spent.
I bought the Delta 1 1/2 HP with 1 micron bag at woodcraft on sale for 200.00.My rigid tablesaw onl has a 2 1/2 dust port,so I bought a reducer to hook up to the Delta.Well aparently I am not getting the full CFM from my Delta now unless I jump through hoops and ladders in modifications.
If I could do it all over again I would buy high end shop vacs for each machine.
ITS A GIANT P>I>M>A
Marc
P.S.
Please,no one send me any links on how to modify my saw.I HAVE THEM ALL and I am not interested

[Cliff Rohrabacher]

That to my mind is the dilemma. If a DC isn't trapping and filtering particles all the way down to something less than One Micron it's a Dust Pump.

To get that level of performance from a DC you will pay a lot. You can build one cheaply enough but you'll still need a powerful and noisy impeller and motor.


If you are going to try and do DC on a budget you might first want to consider whether you want to clean the air you are breathing or whether it's the crap that builds up under the saws etc.

For my money (and space) I'd rather clean the air and sweep or vacuum the chips. There are a lot of guys who built their own air filters from plywood using slide-in air filters using progressive filters down to less than 1 micron. they use squirrel cage fans (which are pretty quiet) and usually hang 'em from the rafters to catch the air borne dust particles.

One micron and smaller is the size that can enter the blood stream through the lungs ( or so I am informed).

[Bill Leung]

Cliff, I already use a Jet air filter and I did notice a big difference in air quality.

Marc, my TS and BS have 4 inch ports so that isn't a problem. To your point, Dust collection is a system and only as good as the weakest link. If you don't have sufficiently sealed hoods on your machines, a lot of the fine dust might not even make it to the DC.

You guys are addressing my original question. I wanted to know if the 1100 cfm DC's are good enough for a small shop or would it still be not sufficient once the filters start getting clogged. It seems like the cyclones move more CFM with lower HP and need less cleaning which are pluses. My main concern is reading articles like in the FWW shops edition, they listed a 1.5hp only being sufficient with a 4ft flex. In my mind that sounds to me like your DC needs to right up against the tool which is not always convenient or possible. I could live with 8-10ft as that would be more workable in a small shop. This prompted my post...are these "bag" DC's just a band aid.

Another point that you guys are bringing up is the environment. Dust collection in a basement shop is much different than a garage that you can open doors and windows. The requirements seem to be much differenct for those cases.

[Wilbur Pan]

Bill,

One of the things you'll find on Bill Pentz's website, if you haven't already, is an Excel spreadsheet that calculates the resistance of the ducting plan you have.

If I plug in the numbers for my setup (8' of 4" flex hose directly to a machine), the resistance is minimal -- about 3 inches of static pressure. Since the static air pressure is so low, a 1.5 HP, 11" impeller, 1100 CFM dust collector should be able to pull 700-800 CFM against that level of resistance.

My conclusion was that an 1100 CFM unit was good enough for a small shop, IF you used short duct runs (8-10 ft of 4" flex hose) and IF it was used in conjunction with a secondary dust clearing system, like an air cleaner or open windows/doors.

I think that the Fine Woodworking recommendation of a maximum of 4' of 4" flex hose is based on the 1100 CFM dust collector being the only unit collecting dust -- no air cleaner, no open windows.

It's best to think of dust collection as a system. Even if the dust collector can't trap all of the dust, having one will make it easier for the air cleaner.

[Brian Kent]

I got the Delta 50-760 for the same size work area. I have had it since December and have much happier lungs and wife.

I got it after reading as many reviews as possible. The clincher was that it already has a 1 micron shaker felt bag. I am sensitive to dust and have had a much better experience with this in place. I still use a respirator when using tools that don't connect to the Delta (such as buffing with diamond dust) and a Jet air filter when there is ambient dust.

[Bill Leung]

Thanks everyone, this has been a good discussion. Sounds like you guys have had good success with the bags. This certainly helps with my decision.

The other factor in this whole equation is that if I eventually get tired of tripping over ducting and moving the DC around the shop I would need a cyclone as the 1100 cfm models will not be sufficient to support permanently plumbing. If a good bag DC is going to cost a minimum of $400-$500, maybe a cyclone might be justified if the bags have limited usefulness.

[Wilbur Pan]

Bill,

You don't have to spend $500 on a dust collector. My JDS Dust Force lists for $350 at Woodcraft. On sale, I got it for $310 and free shipping. Amazon lists it for $300, plus shipping, but they also have free shipping sales every so often.

The Delta 50-760 that Brian mentioned goes for $300-350. The only reason I didn't get that machine is because I have low ceilings in my basement which would not accommodate the height of the bag on that machine. Otherwise, I would have gotten the Delta machine instead.

If you are concerned about costs, remember to factor in the cost of permanent duct work if you go the cyclone route.

As far as moving the dust collector around, my shop is arranged so all the machinery is at one end, which allows me to park the dust collector at that end and just move the flex hose from machine to machine. If your machinery is placed across your 10' x 20' shop, then placing the dust collector in the middle of the shop would be an ideal spot.

[Bill Leung]

Wilbur, I know the pricing of the DC itself will run 350ish. I'm including the cost of a Wynn caninster which adds another $80 plus shipping etc. That's how I get the price to $500. The Jet 1100 cfm 1.5 hp is even $450 on the current sale. I guess the question is are the stock 1 micron filters that come with these units adequate? From Bill's site, it doesn't sound like it which is why I added that into the price.

My garage has 8ft plus ceilings so I'm good on height. As far as big powertools go, I currently only have a TS, CSMS, and BS so moving around the duct should not be an issue but when I get the router table, jointer and planer, that may make it a bit harder to squeeze things to one side. My thought around the cyclone is that I could still run flex line until I figure out the shop layout and then start laying permanent plumbing when I have all the main tools.

Cost is always a concern but not really the reason for the post. I am trying not to upgrade equipment after a short time though and be smarter that way, saving money in the long run. Even if I bought a DC for $300, if I were to upgrade, I wouldn't get more that $150 on resale.

My question was really targeted at determining whether the DC can really do the job (within reason). It sounds like from Bill's site and magazine articles, their effective operating window is pretty small. Although I believe there is merit there, I found it hard to believe that these systems don't perform as I know just from this forum that 100 or 1000's of WW's like yourself are using them successfully and not scraping them to buy a 3hp+ cyclone. Since I don't have a DC yet, I have the luxury of going either way. It helps a lot to hear that people are in fact doing fine with the $300 models and not coughing up a lung after a wood working session. I started thinking about this post after reading what people are saying about the Sawstop. People can justify spending 5k or to prevent loosing a hand or finger, so I started thinking why is dust collection any different. How much are we willing to spend to save our health? I know many on the site recommend cyclones but unlike saws which you know will cut wood great without the safety features, do the non cyclones, do just as good a job (without the maintenance).

I am not trying to justify a cyclone but trying to find out if the bags can match up and do the job.

[Ray Phillips]

I went through this process about 3 months ago. I have a small shop 13x30. I have all my equipment on wheels. I ended up purchasing the Jet 1100 DC and the 750 air filter. I placed the DC in the center of my shop against a wall and ran 4" PVC ducts with blast gates to my RAS, BS and router table. I then ran a duct across the shop to the other side 13 feet to my mini lathe and sanders. Since I am just a hobbiest and not a pro I can only use one machine at a time. When I use a particular machine I open that blast gate only. This system has worked very well for me. If I had a larger shop I would have purchased a cyclone system, but I am very happy with what I have now. It beats a broom and dust pan and a shop vac.

[glenn bradley]

I'm in approx. 20 x 30 feet of gara . . er, shop. I have a 1HP Delta with a second stage trashcan. Along with the fact that I can open the garage door and the side door, this little guy does a good job on one tool at a time. If I were in an enclosed space or couldn't open the 'wall' and get flow through ventilation I am sure it would be inadequate.

There's a cyclone in my future (at least in my mind) and plans to re-deploy the 1HP to fixed duty on whatever tool seems to make sense as the shop progresses. For now, my environment, as described is very workable.

[Wilbur Pan]

I am not trying to justify a cyclone but trying to find out if the bags can match up and do the job.

Bill,

Long story short, the cyclones certainly will do a better job, but I think that the performance benefit for a small shop is minimal.

I certainly don't want to discourage you from getting a cyclone system if you have the budget and space for one. However, I don't worry so much about the performance of the 1 micron filter bags that come with the 1 1/2 HP dust collector systems out there. There are two reasons for upgrading the filter. The first is that the bag may not be truly be a 1 micron filter, so that you are pumping 1 micron dust throughout your room. This would be a concern only if your dust collector is the only way to trap dust in your workshop. The fact is, even the best cyclone system can't trap all the dust at the source. If you do a search here on SMC, you'll find a thread outlining the fact that even high quality cyclone setups will result in airborne dust. If this is the case, I'm not going to worry too much about the performance of the bag in a 1 1/2 HP dust collector, as long as it's a 1 micron bag. Instead, I would concentrate on plan B (ways to trap dust that the dust collector missed), be it a high quality air cleaner or opening doors and windows. Furthermore, as the bag gets caked with dust, it will trap finer and finer particles. I agree that Wynn makes excellent filters, but I have not seen the need to upgrade my dust collector bag. If I was going to do any filter upgrading, it would be in my air cleaner. I do think that upgrading or adding air cleaner units is the most cost effective way of increasing the collection of fine dust, second only to opening windows.

The second reason that there are concerns about dust collector bags is the thought that as they become caked with dust, the performance of the dust collector will drop. However, the resistance of your ducting will have a far greater effect on dust collector performance than how clogged your filter bag becomes. The impact of a clogged dust collector bag would be decreased ability to trap 100% of the fine dust at the source, but as we've already established that this is not possible, we're back to dealing with plan B again.

If you have the budget and space for a cyclone system, I would go for it. The main reason I don't have a cyclone is that I did not have the space for it, not budget. If you decide that you need to go with a 1 1/2 HP 1100 CFM system, as long as you can keep ducting runs short, I wouldn't lose too much sleep over it. In either case, I would concentrate on plan B -- air cleaners and/or windows and doors.

[Steven Wilson]

You guys are addressing my original question. I wanted to know if the 1100 cfm DC's are good enough for a small shop or would it still be not sufficient once the filters start getting clogged.

The typical 1100 CFM bag collector (which is free air CFM without any bags or duct attached) runs at about half to 2/3 of that CFM which means it's marginally able to collect from machines with the needed 600-800 CFM of flow at the DC hood. If you hook it up to a bunch of pipe it won't be sufficient. As for filtering capacity, the typical bags sold are useless for filtering the fines. You either need properly made bags (which will have a lot more filter area and reach your roof) or a pleated cartridge. So, a Jet DC1100C using a short segment of 6" hose will work quite well on many hobby machines if you wheel it from machine to machine.

2 1/2" and 4" machine ports are generally there for marketing, not your health, and aren't designed for proper collection. You will need to redesign and rebuild these ports if your serious about dust collection.

Your lungs breath the same air that Air Cleaners are cleaning. For filtering fines while you're working air cleaners are useless. To clean up ambient air prior to finishing air cleaners are usefull. Air cleaners will not help your lungs at all.

If you can't collect it properly at source wear a respirator.

[James Hebert]

I recently installed a Harbor Freight 2hp unit for a 1 car garage size hobbiest shop. I ducted allt he stations with 4" sewer and drain PVC and plastic Jet blastgates for each station. I have 6 stations/blast gates and the farthest about 20ft from DC. I normally open one gate for a machine but on occasion get lazy and keep the tablesaw and the chop saw gate open and stillt here is plenty of plenty of suction. I also installed the Wynn Environmetal filter which improves the HF 30micron 30sqft filters to 0.5 micron 300sqft filter with clear plastic collection bag. It works phenomally well and im sorry I didnt do this years ago. Prices paid are below:
HFDC $134 on sale and with 20% off coupon, 2hp 1600cfm
Wynn kit $91 (mail order)
4" pvc sewer and drain (Lowes) about $0.70/ft and fittings about $1.25 ea.
Jet Blastes gates from Amazon, $1.50
Some flex hose. Rockler has the best clear flex hose.

The HFDC is identical to the Delta, Jet etc 1.5 hp 2 bag units from same OEM but at 50% or less the cost.

[Bill Pentz]

Bill,

I slipped my answers into your questions in blue, plus added some background after. Hope this helps.

bill

Hi all,

I have a question regarding dust collectors. Reading through all the past post has me more confused now then when I started. I need to get a dust collector for a smaller shop (10x20 single car garage) and am a hobbyist, I don't have the tools that make a lot of dust (jointer, planer, oscillating sander) but hopefully will in the near future.

My question is this.
For single tool dust collection, will a 1.5 hp, 1100 CFM (Jet or Delta) be good enough (1 or 2 micron bag)? The 1.5 hp dust collectors are great for “Chip Collection” meaning collecting the same sawdust and chips we would otherwise sweep up with a broom, but almost always lack both the airflow and filtering needed for good fine dust collection. The issue is with a good 6” smooth walled flex hose going to a tool with two ports like a table saw with a cabinet port and blade guard port we still pull about 3.6” of resistance with a clean filter. As the filter builds up a cake of dust the resistance pressure can easily rise to over 6”. At 6” pressure these blowers with 11” diameter impellers only move about 425 CFM. Although we only need about 350 CFM for good “chip collection” to keep our shops look clean, decades of professional engineering shows we need 800 to 1000 CFM at our larger tools to ensure capturing the fine airborne dust. With dust lasting six months to years before it dissipates or breaks down, in an enclosed shop the dust that we miss during collection or that goes through our too open filters will build to very high levels. Airflow from our tools, fans, dust collection systems, air compressors, etc. will launch this “fugitive” dust over and over. Since most of this dust is smaller than 10-microns, roughly one tenth the thickness of a human hair and we can only see down to about 10-microns, it is invisible. The result is we end up with clean looking shops that create a false sense of security because the airborne fine dust levels just keep growing to dangerously unhealthy.

Will you need to put on a Wynn filter anyway (adds another $80-$100 to the price). I have long recommended replacing all of the more open filter bags with a good cartridge filter. Unfortunately, if you don’t also do some serious pre-separation, these cartridges are going to clog, pose a constant cleaning problem, and need replaced roughly every 300 hours of use. Filter material makers recommend at least 1 square foot of filter area for every 2 to 4 CFM of airflow to prevent 1-micron and finer filters from loading up too quickly. A typical dust collector bag has about 30 square feet of area, so these are going to load up and become a constant cleaning problem. This loading kills our airflow by adding lots of resistance, plus rapidly ruins filters from excess cleaning and the increased pressure forcing the sharp particles to cut and tear their way through the filter pores. The exception is of course vendors that instead provide 10 to 30-micron filters which load up far more slowly. Sadly, many vendors play games with filter ratings. The standard set by ASHRAE is indoor filters need measured when clean and new. Most of the filters found on small shop dust collectors and cyclones are measured after the filter has become plugged or at least fully seasoned meaning built up a heavy cake of dust in the filter pores that does not come out with normal cleaning. That dust improves filtering, but kills our air flow unless the filters are big which is near impossible to achieve with a bag or smaller cartridge. Adding enough dust to any filter will eventually get any desired level of filtering, but we also lose our airflow needed to collect the dust. So to answer your question I personally use a large Wynn all poly cartridge filter on my Jet DC-1100 or use my cyclone with its fine filters. I also always use an exhaust fan sitting in a doorway, plus wear my 3M NIOSH approved mask whenever making fine dust.

With the total cost coming to around $500, does it make sense to get a lower end Cyclone with cost $800+shipping which brings the price to $1000. My own testing shows most small shop cyclones are “chip collectors” that have fine filters added. Since these separate little better than trashcan separator lids, I don’t recommend them unless you can forget the filter and vent directly outside.
Thanks in advance.

Bill,

We have three major approaches to dust collection today.

1. There are no standards enforced for small shop dust collection, so whatever we will buy is what we get.
2. For shops in commercial buildings subject to regular fire marshal inspection most must comply with local fire and building codes which mostly come from the National Fire Protection Association (NFPA) guidelines. These guidelines cover a wide range of areas which many call “chip collection” meaning picking up the same chips and sawdust that we would otherwise sweep up with a broom. Dust collectors and cyclones need certified as fire and explosion proof or instead put outside. The cost for certification is expensive, so most put their dust collection outside.
3. Fine dust collection maintains minimum air quality standards compliant with either OSHA, ACGIH, or medical air quality standards used in Europe. OSHA only regularly tests the air quality in the largest woodworking facilities with many workers, so most shops have no enforced standards.

Both “chip collection” and “fine dust collection” have decades of engineering and refinement shared to define exactly what is required.

Chip collection has been done for over sixty years and is well understood. For good “chip collection” we need:

1. Hoods which block and trap the dust being ejected from out blades, bits, and cutters. Our tools tend to launch dust and chips at over 100 miles an hour and our dust collection airspeeds are more like 40 miles an hour so if a hood is not well designed and in the right place, the dust is going all over.
2. Roughly 4000 feet per minute (FPM) airspeed with about 350 cubic feet per minute (CFM) air volume will effectively pick up the heavier sawdust and chips.
3. Ducting with a cross sectional area equivalent to a 4” diameter duct will carry this much airflow at the needed internal ducting speeds.
4. An internal ducting airspeed of about 3800 FPM in vertical runs and about 2800 FPM in horizontal runs to keep the dust entrained, meaning kept airborne. Dust that settles in a duct poses a serious fire risk. When these piles break loose they can damage blower impellers, motor bearings and filters, plus the sudden surge of dust when a duct pile breaks loose creates one of the few instances where a small shop can create a potentially explosive dust to air mixture.
5. Open filter bags that trap particles sized larger than about 30-microns where 30-micons is about one third of the thickness of a human hair. Most airborne dust that does not quickly settle is sized 30-microns and smaller.
6. The 30-micron filter bags need a minimum of roughly one square foot of filter area for every 20 CFM of airflow to keep from clogging too quickly, so a typical small shop 350 CFM dust collector needs at least 16 square feet of filter area. Doubling the filter area will cut both cleaning and resistance four fold so most small shop dust collectors come with two bags for roughly 30 square feet of filter area.
7. Chip collection in compliance with normal building and fire safety codes will use all grounded metal ducting, metal instead of cardboard chip collection, and put all dust collectors and cyclones outside that are not certified to be fire and explosion proof.
8. Note: Using finer filters can pull off the fine dust collected, but does not move the air needed to collect much of the fine dust. Fine filters have far more total open surface area due to the fine filter strands blocking less air, so a new fine filter will move far more air when the filter is clean and new. Unfortunately, this is only a temporary advantage. As fine filters season with a permanent cake of dust in the filter strands that does not come out with normal cleaning resistance increases significantly over more open filters. Fine filters require far more filter area or lots more cleaning. Many vendors confuse this issue by selling fairly open filters which trap much of the visible dust while passing the unhealthiest 10-micron and smaller fine dust. This lets them get away with cartridge filters that only have about 1 square foot of filter area for every 10 CFM and not force too much cleaning. Meanwhile the unhealthiest invisible dust blows right through and begins to collect in our shops soon creating clean looking shops with dangerously unhealthy airborne dust levels. With cyclones that separate off most of the 30-micron and larger particles, open filters can take months to years before they actually provide the vendor advertised filtering. Most who use fine bag and cartridge filters on typical dust collector and cyclones end up being very unhappy with the increased need for cleaning, much worse overall airflow and often poor filtering.

Likewise, fine dust collection has been done for decades and is equally well understood. The tough part is ignoring hobbyist and small shop “chip collection” advice and staying focused on professional firms whose customers must pass regular air quality inspections. Fine airborne dust spreads so quickly that decades of testing established there is almost zero chance of either an exhaust fan or air filter pulling down the dust level fast enough to avoid failing an air quality test. I use a good air cleaner as it helps with the inevitable dust missed during collection and it saves on dust ruined finishes. Regardless, this means we either figure out a way to collect the fine dust at the source or we will not have good fine dust collection. Festool and a few others have shown that by using tools designed from the ground up with good fine dust collection built in to totally contain the fine dust a good shop vacuum provides ample fine dust collection. Unfortunately, most of us instead use larger tools which are copies of units made often without even good “chip collection” built in. For good fine dust collection on our traditional tools that captures the fine dust air engineers have found we need:

1. Hoods which block and trap the dust being ejected from out blades, bits, and cutters. Plus our hoods must also contain the fine dust that is often launched from other parts of our tools. I did extensive air quality testing during the last quarter of 2006 and not one single shop passed its air quality test at any level regardless of the size of cyclone or dust collector if the table saw did not have a good blade guard dust hood that blocked the fine dust from being ejected.
2. Roughly 4000 FPM airspeed to effectively pick up the heavier sawdust and chips, plus roughly 50 FPM airspeed all around the dusty portions of our tools to pull in the fine dust before it can be spread by normal room air currents. We have to provide that 50 FPM over a large area. From using our vacuums we know that sucked air which comes from all directions maintains its air speed for only a very short distance. To cover a larger area we need to move lots more air. Careful testing shows that our larger tools need about 800 CFM to pull in enough dust to meet OSHA air quality standards. We need about 900 CFM at our larger tools to meet the five times higher ACGIH standards that most commercial firms voluntarily follow. And, we need about 1000 CFM to meet the fifty times tougher than OSHA air quality standard that pulmonary doctors recommend which is already the standard in the European Union.
3. Ducting and tool ports with a cross sectional area equivalent to a 6” diameter duct will carry the 800 CFM required to meet OSHA air quality standards. We need either a higher pressure blower or ducting sized 7” in diameter to meet ACGIH and medical air quality standards.
4. An internal ducting airspeed of about 3800 FPM in vertical runs and about 2800 FPM in horizontal runs to keep the dust entrained, meaning kept airborne.
5. We need roughly 2-micron filters to meet OSHA air quality standards, 1-micron filters to meet ACGIH air quality standards and 0.5-micron filters to meet European Union and medical recommended air quality standards. The filter material maker tables show at the OSHA 800 CFM and 2-micron filter level we need a minimum of about 100 square feet of filter with most recommending at least 200 square feet or more. At ACGIH 900 CFM levels and 1-micron filters we need more like 150 square feet of filter with most recommended at least 300 square feet or more. At medical air quality 1000 CFM levels with 0.5-micron filters we need more like 200 square feet of filter with most recommending at least 400 square feet or more. And yes, I am fully aware that this is a controversial area where many claim half as much will work just fine. Half as much filter area will work but you then need to replace expensive filters four times as often.
6. Like chip collection good fine dust collection in commercial facilities subject to fire marshal inspection also requires compliance with normal building and safety codes using all metal ducting, metal instead of cardboard chip collection, and putting all dust collectors and cyclones outside that are not certified to be fire and explosion proof. If we build good systems that keep up enough air speed to keep all clear, the science and physics shows that we can use plastic ducting, cyclones, and other components, but I still recommend use of metal collection bins in lieu of cardboard bins simply as a good fire prevention measure.

As you can see, there is far more to good fine dust collection than "chip collection". I recommend you spend the time on my Cyclone and Dust Collection Research web pages to figure out what is most appropriate for you.

bill

[James Hebert]

itll work fine and even more then you need. Just put a 20 gal trashcan for chip collector before the impeller and it will difuse the chips and so heavy loads like from planer wont be a problem at all. Dont get sucked into the dust paranoia/fanatic dilusions. The $ spent for what they claim is minimal will buy you .01% improvement over the $135 2hp 1600cfm HF DC. The Wynn $91 filter is nice, but the 30 micron bags that come with the unit will suffice just fine.