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  • #16

    Re: dust collector confusion

    Re: dust collector confusion

    You got some good advise about Dust collection. Read everything you can from Bill Pentz. One thing to consider is the hell that Oneida put Bill through, that caused him to start his dust collection crusade. I personally wouldn't buy Oneida if it was the last DC available on the market. There are a lot of other good DC's out there and some good info on this site about some of the newer space saving DC's and their inefficiencies. Not all DC's are good and most come with major amounts of BS in their specs.

    John

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    • #17

      Re: dust collector confusion

      Re: dust collector confusion

      Some thought should also be given to the types of chips and dust you will be generating. Wood shop cyclones vary somewhat in design and are not built to be particularly efficient at separating fine dust. Long stringy shavings from a straight knife planer need more cfm than chips off an insert head. Factor your needs into the design. Oneida recently went to a material similar to Clearvue on some of their units. It would be good to know if they incorporated some of the features that make the CV better at separation ( Ramped inlet, helical fins ) that their steel units lack. Commercial cyclones like Torit, Dustkop, STernvent etc have included some better designs for years but the cost is much higher. They can sometimes be found cheaply used. I paid $400 for a used Torit 20-5 cyclone, motor and impeller. Added cartridges, made a plenum, and added a vfd to control speed and allow for soft start. All wood cyclones are rated for dust over 10 microns and are more like 50-60% efficient for smaller particles so the filters need to be easy to clean if you are doing much sanding. I run cartridges on the main system but have a direct bagger with oversize Singed polyester felt bags on the Widebelt. The Baldor motor used by ONeida is a very good motor. CV uses a smaller frame ODP on their single phase system but a larger frame on their three phase. Larger frame is better as the shaft and bearings are better. CV has better separation ( IMO- no real data is available ) and a taper lock bushing rather than double set screws which is a better way to attach the impeller. Neither unit is built anything like the commercial units. Filter area is very important. Slowing the air going through the filters helps with the cleaning and most systems will really benefit from an additional filter. Most systems utilize a curved blade low pressure impeller to keep from overamping the motor so getting the pipe size right is a big deal. Lots to study. Dave

      I'm not criticizing either Oneida or CV here. They sell units that are cheap and affordable. People here tend to cheap out on DC. Euro units like the Felder and others run more like 4-10K as do commercial systems. We have to realize that there are compromises to buying a complete system for under 2K.
      Last edited by beckerkumm; 02-08-2015, 09:15 AM.

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      • #18

        Re: dust collector confusion

        Re: dust collector confusion

        Chris,
        Brand bashing aside.......

        Depending on what you decide to do in your shop, the entire collection circuit must be right. You can buy mega cfm rated single stage units, slap a so called HEPA cartidge of the exit and quickly have mini cfm flowing.

        1. Capacity. You say 800 CFM. Sustained flow at the tool is where this number is meaningful. How do you ensure this can happen? At the design stage, apart from hiring an engineer, the only tool I know of is Bill Pentz Static calculator.
        http://www.billpentz.com/Woodworking...staticcalc.xls

        What this teaches you is there are limits to how much air a given fan size and motor HP can deliver through a given size of duct. So you will very quickly understand that the 4" based dust collection industry in North America is promoting some very questionable performance specifications. The cool part of this bit of knowledge, is you can take an underpowered single stage blower, knock off the splitter suction, attach a 5" or 6" duct and service one machine economically without having to run costly ducting all over your shop.

        2. Vortex or Mechanical Separation. The last thing you want to rely on is the whole process for clean air is the exhaust filters. You want extremely efficient physical separation in the cyclone. This efficiency should be rated in % of particulate size , not % of particulate weight. Simple logic is, if you are extracting 99%+ of the particulate by size in the cyclone, the weight will be there as well. This is a tough one to research and verify. Pentz says his design takes out 99.% of particulate down to 4.7 micron. It would be nice to have comparisons. good separation, regardless of device means more trips to empty the waste bin. A waste bin overflow is totally bad!

        3. Exhaust Filtration.
        • [*=1]Surface Area. Anyone who has converted a single stage DC from felt bag to pleated cartridge should have noticed a significant performance increase. The main reason for this is the increase in surface area reduces the pressure drop across the filter. An all to often ignored specification. You should target for 1 square foot of filter surface for every 2 CFM of capacity. The pressure drop is not linear. According to Wynn Environmental, a 200 sq ft element has 1/4 the pressure drop of a 100 sq ft element.
          [*=1]HEPA. People get all excited over HEPA. True HEPA was originally developed to trap AND hold radioactive particles. It now common in many clean room operations. True HEPA is typically the last stage in a progressively more rigorous filtration process. The question is, if you can clean a HEPA element, doe you have HEPA? I do not know this answer. I would think any cleaning would destroy or seriously damage the structure. The best answer would be that the cyclone in front of the element is so efficient that minimal particulate gets through, greatly extending the life of the element. Is this possible? I think not. Companies like Wyn Environmental, Camfill Farr and Donaldson do not promote HEPA elements in their wood working offerings. Everyone should read about HEPA, not just the numbers.


        Many have commented over the years that we seek to have our workshops cleaner than the street, and probably they are correct other than for the fact that for brief periods of time, our exposure gores off the charts. I know I cannot see anything smaller than 40 microns unaided, I doubt there are many who can. Can anyone say for sure that 1 micron bag is better than a 10 micron? For about 10 minutes, then it is so plugged up, the ,overall efficiency drops. A 1 micron bag is between 30 an 50 sq ft. Repalce with a 100 sq ft cartidge and you notice the cfm seldom dropping.

        I do not believe any of the devices available negate the need for a good personal respirator if you are generating hazardous dust.

        You have to walk the line and decided. All of the opinions you read are totally subjective, base on no real comparative science. There are no performance standards for the equipment, no accountability to the manufacturers.
        Read Bill Pentz. He gets criticism only for commitment, no one has ever challenged his science - that I have read.

        This hobby is dangerous. There are all manner of unknown toxins in the wood we work with. Cedar, walnut, kentucky coffee tree can get you as badly as peanuts at a baseball game.

        In the end, you wan to move the bad stuff away from you and isolate it.

        Good collection/hoods at the tools, good cfm at the tool, excellent mechanical separation and clean air back to the work space. If all of these elements are not present, your results will not be optimal.

        another DC soapbox.

        Don

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        • #19

          Re: dust collector confusion

          Re: dust collector confusion

          How you dispose of the toxic dust inside the filter is another place to be careful! It is easy to get a few mouthfuls while emptying it.
          Rob

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          • #20

            Re: dust collector confusion

            Re: dust collector confusion

            Originally posted by iamtooler View Post
            How you dispose of the toxic dust inside the filter is another place to be careful! It is easy to get a few mouthfuls while emptying it.
            Rob
            You too 😱!

            Don


            Sent from my iPad using Tapatalk

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            • #21

              Re: dust collector confusion

              Re: dust collector confusion

              Don gives good advice. Every filter media is rated for cfm per sq/in and that rating should not be exceeded. Operating cfm at the machine will be much different than the ratings from the manufacturer. A 3hp 14" impeller will deliver in the 600-1000 cfm range depending on a million variables, a 15" 5 hp will be in the 800-1200 range and not fully max the motor. A 16" impeller will get you in the 1000-1400 cfm working range. Curved impellers will deliver more cfm/ amp at low pressure, radial straight blade will deliver more cfm at higher pressure and should be considered if the piping is a little undersized, runs are long, or speed control is used. Keep in mind these numbers are approximations. Different cyclones cause different pressure drop, as do different filter media, radius of ells, size of pipe, and velocity of air. Cyclone efficiency is optimized if the velocity going into the inlet is within the design of the cyclone diameter and cone length. Fine dust cyclones typically are much longer, have an involute inlet, a vortex breaker, and more pressure drop than a small system can handle. That means the filters must allow themselves to be cleaned without degrading the media. Questions to ask are about cfm rating, cleanability, length of time before the media degrades, and then about filtration efficiency. Most people ask the questions in the wrong order. Also keep that in mind when converting a direct bagger to cartridges. Might get more cfm initially but oversize bags can get you to the same place and clean more easily as the chips don't get caught in the media. I run 8' bags in my dedicated direct portable machines rather than the cartridges in the main system. Dave

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              • #22

                Re: dust collector confusion

                Re: dust collector confusion

                Originally posted by iamtooler View Post
                How you dispose of the toxic dust inside the filter is another place to be careful! It is easy to get a few mouthfuls while emptying it.
                Rob
                Good point Rob, if you have the foresight you buy washable filters that can be cleaned by filter services that trucks and heavy equipment use. That dust, in the concentration it's in, is more toxic then anything will will get in your shop while actually woodworking.

                As for what Don says about good particle separation before the filters, that's key and if you email Bill, he and his team have tested hundreds of systems and may have the data you are looking for on a particular setup. Observation over the years of using a system is also extremely valuable.

                As for brand bashing some companies have ethics and tactics lower then snake st!t, you and anyone else can buy from who you like, that's your choice as well as mine.

                John

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                • #23

                  Re: dust collector confusion

                  Re: dust collector confusion

                  John,

                  Where did you get your information regarding Oneida having been the company which caused his health to fail? That's the first time I've ever heard such a claim...

                  Originally posted by John JMK View Post
                  You got some good advise about Dust collection. Read everything you can from Bill Pentz. One thing to consider is the hell that Oneida put Bill through, that caused him to start his dust collection crusade. I personally wouldn't buy Oneida if it was the last DC available on the market. There are a lot of other good DC's out there and some good info on this site about some of the newer space saving DC's and their inefficiencies. Not all DC's are good and most come with major amounts of BS in their specs.

                  John
                  All the best,

                  Marty

                  - Instagram: @apexwoodworks
                  - facebook: https://www.facebook.com/Apex-Woodwo...0243458908979/

                  Secretary of Kingston Wood Artisans Inc. https://kwoodartca.wordpress.com/

                  Master Mistake Fixer (because I've made them all... at least once)

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                  • #24

                    Re: dust collector confusion

                    Re: dust collector confusion

                    An important issue that seems to be overlooked in these discussions is the collection point at the tool. I could have the best dust collection that Bill P could design, but if I hook it up to a contractor table saw with stock collection, I would still have a dust belching saw. The same holds true of many tools. Not many tools are designed for optimal dust/shaving extraction. So, you either make do, or take it upon yourself to do some serious modding of your tools.
                    Grant Wilkinson
                    Ottawa ON

                    Comment


                    • #25

                      Re: dust collector confusion

                      Re: dust collector confusion

                      What a great thread! I wish I had read a thread like this before building my DC system. I made ALL the mistakes mentioned here. I didn't study enough in advance b/c there was just too many opinions on the Internet, I couldn't sort them out. So I just bought a machine and started running pipe. I cheaped out on the machine, and then was shocked to find that I spent more on pipe and hose than the machine! The final result does a satisfactory job clearing chips, but not giving clean air. The machine is underpowered, the pipes are too small, i'm not done upgrading yet and already I have spent enough on upgrades that I could have just afforded abetter system to begin with! Don't make my mistakes!

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                      • #26

                        Re: dust collector confusion

                        Re: dust collector confusion

                        Marty when I first started doing my research in 2006 this info was available in multiple discussions and on Bill's own website. The website has taken on a new look over the years and the info has been refined. Not many names are mentioned now but the inference is still there. A lot of changes have been made in the small cyclone industry as a result of Bill's work but there is still a lot of smoke and mirrors. Don't really care if you believe or not, if your happy with your system that's great.

                        John

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                        • #27

                          Re: dust collector confusion

                          Re: dust collector confusion

                          I didn't realize it was an Oneida system that Bill used that allegedly caused all of his health problems. I think Bill's work has been a great service to woodworkers, and i really hope some day that all DC manufacturers are required to provide independent proof of their system performance from suction/air flow at the inlet to particle capture by their filters. As someone wisely said, that's not the whole picture because it doesn't guarantee complete pickup at the tool, but at least it's a reliable starting point. Right now, there are only a couple of companies that do this, and Oneida is one.

                          I read online that a side by side comparison of Onaida to clearview showed cyclone seperation for Oneida to be 98.4% and Clearview 99%. This doesn't mean that the difference isn't captured by the Oneida, it just means it gets past the cyclone to the filter....which in the case of Oneida (and some others) is genuine HEPA. Does that mean the filter gets clogged faster? The past 6 months or so, my shop has been pretty heavily used, but my compressor wasn't there to blow out the filter, which I normally do daily. I have a back pressure gauge that helps to show when the filters are getting clogged, and even after 4 months of using the DC 4-6 hours a day 5 days a week, my back pressure never got to the point where I was supposed to stop using the DC. It climbed a little bit all the time, but never got to the critical point. So if it's getting clogged faster due to 98.4% separation vs. 99.?% separation it still ain't getting clogged fast! All that to say, I expect the two are pretty much neck and neck in many aspects or performance.

                          B
                          Proud member of the Wadkin Blockhead Club.

                          http://www.youtube.com/c/DovetailTimberworks

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                          • #28

                            Re: dust collector confusion

                            Re: dust collector confusion

                            Bill Pentz is the far end of the spectrum. His personal health issues seem to have pushed him to the extremes. While he may need the alarmist version of dust collection, I do not believe that it is necessary for most people. Just too judgmental on anything most people can afford.
                            Mike

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                            • #29

                              Re: dust collector confusion

                              Re: dust collector confusion

                              Originally posted by timberframe View Post
                              The past 6 months or so, my shop has been pretty heavily used, but my compressor wasn't there to blow out the filter, which I normally do daily.
                              Just some food for thought...

                              Compressed air can damage filter media. A cheap leaf blower operates at lower pressure, but higher volume. If blowing inside out, it reaches into a canister filter too. I don't know if it's the right recommendation, but it works really well.

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                              • #30

                                Re: dust collector confusion

                                Re: dust collector confusion

                                Originally posted by Kevin H View Post
                                Just some food for thought...

                                Compressed air can damage filter media. A cheap leaf blower operates at lower pressure, but higher volume. If blowing inside out, it reaches into a canister filter too. I don't know if it's the right recommendation, but it works really well.
                                You're right. Oneida gives instructions on how much PSI to use, and how close to the filters to put the nozzle.
                                Proud member of the Wadkin Blockhead Club.

                                http://www.youtube.com/c/DovetailTimberworks

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