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Thread: Dust Collector too small (HP) and locating in garage create dust on cars?

  1. #1
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    Dust Collector too small (HP) and locating in garage create dust on cars?

    I bought a 2HP Super Dust Gorilla in December of 2008. My new shop with attached garage is now complete. I mounted the dust collector but have not installed pipe. Still playing with pipe design in Sketchup.

    After some time using Sketchup I decided it would make more sense to put the dust collector on the garage side, you know, the side that is supposedly for cars and meant to remain somewhat clean.

    I am the only user so only one machine operating at a time.

    All piping is to be 6" S&D from DC to each tool.

    Distance from DC to SCMS would be about 31' 270 degrees of turns.
    Distance to TS would be about 40' and 360 degrees of turns.
    Most other machines are further,maybe 45'. Jointer, router table, band saw, drill press.

    So my questions are:

    1. Is my DC underpowered? The more I read the more I see people using 5 HP DCs (mostly clear vue folks). I emailed Oneida mid-day today (Friday) to see if I can get a more powerful motor for my DC. Haven't heard back yet.
    2. Locating the DC in the garage has benefits, lower noise, DC is not taking up shop space. But will I regret it if it creates dust on the garage side? Has anyone had the canister connection fail and end up with a giant dust cloud? (Hopefully this is very rare.)

    The Super Dust Gorilla is very heavy! I want to relocate it this weekend but won't bother if the consensus is to sell it and get something bigger. Weight is not an issue once mounted, but moving it, oh boy!

    The Super Dust Gorilla is a very nice looking machine with it's bright yellow paint job. The clear Vue is highly regarded, just doesn't look as nice.

    Keep it?
    Upgrade it to a bigger motor (is this possible?)
    Put it on Craig's List and get a more powerful machine?


    Thanks for any and all advice/opinions.

  2. #2
    I run a 2HP and have much shorter runs than you. Longest is maybe 25 feet. I sometimes wish for more power but, couldn't physically fit a larger unit. Maybe others with long runs could chime in.
    “If liberty means anything at all, it means the right to tell people what they do not want to hear.” -- George Orwell


  3. #3
    Those who slavishly follow Bill Pentz as the authority will tell you that nothing short of 5HP with one of his designs with the appropriate ramped vanes, yada ydada will suffice.

    I've got a 2HP griz which has a 7" input wye-d down two 2 6" trunks around my shop. Works fine. The cyclone itself sits outside the shop in the adjacent aircraft hangar. Believe me, sawdust in the air out there would have my wife going crazy. Don't get obsessed over your configuration unless you realize and actual problem.

  4. #4
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    It's bed time over here Todd, but some basic points:

    1. It depends on what CFM you are shooting for. Around 400CFM is the recommended min for chip collection on most (smaller) floor machines, but up to and above 1,000CFM on especially larger machines if you buy the Pentz doctrine (which practice shows time and again checks out) on creating a large enough low pressure volume around the cutting process to capture the fine dust. You then need HEPA cartridge filters from a reliable source to catch that fine dust, and a cyclone to stop them blinding too quickly.

    2. To get up towards the higher numbers requires around 3HP minimum, and that's with short hose runs as found on say a mobile unit. Longer runs and more bends will drop you back towards the lower CFM numbers.

    3. Longer runs like what you seem to have require more like 5HP - that's maybe something over 4HP running steady state.

    4. There's no point fitting a larger motor on a fan - it won't move any more air. For a given RPM the CFM at a given pressure is determined by the size of the fan impeller. It takes a 15in or better still 16in like the ClearVue to properly load a 5HP 3,450 RPM motor. The other advantage of a larger impeller is that it delivers much better performance at higher pressures, and so is less disturbed by the likes of a slightly restrictive hood or an extra bend or two.

    Bill P's tables in sections 1 and especially 5 here provide a pretty good summary: http://billpentz.com/woodworking/cyclone/DCBasics.cfm

    ian

  5. #5
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    Quote Originally Posted by ian maybury View Post
    It's bed time over here Todd, but some basic points:

    1. It depends on what CFM you are shooting for. Around 400CFM is the recommended min for chip collection on most (smaller) floor machines, but up to and above 1,000CFM on especially larger machines if you buy the Pentz doctrine (which practice shows time and again checks out) on creating a large enough low pressure volume around the cutting process to capture the fine dust. You then need HEPA cartridge filters from a reliable source to catch that fine dust, and a cyclone to stop them blinding too quickly.


    4. There's no point fitting a larger motor on a fan - it won't move any more air. For a given RPM the CFM at a given pressure is determined by the size of the fan impeller. It takes a 15in or better still 16in like the ClearVue to properly load a 5HP 3,450 RPM motor. The other advantage of a larger impeller is that it delivers much better performance at higher pressures, and so is less disturbed by the likes of a slightly restrictive hood or an extra bend or two.

    Bill P's tables in sections 1 and especially 5 here provide a pretty good summary: http://billpentz.com/woodworking/cyclone/DCBasics.cfm

    ian
    1. The whole CFM calculations thing make my head hurt.

    4. That makes sense. I wonder if I can get a bigger fan and motor for my system.

  6. #6
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    Quote Originally Posted by Ron Natalie View Post
    Those who slavishly follow Bill Pentz as the authority will tell you that nothing short of 5HP with one of his designs with the appropriate ramped vanes, yada ydada will suffice.

    I've got a 2HP griz which has a 7" input wye-d down two 2 6" trunks around my shop. Works fine. The cyclone itself sits outside the shop in the adjacent aircraft hangar. Believe me, sawdust in the air out there would have my wife going crazy. Don't get obsessed over your configuration unless you realize and actual problem.
    Thanks Glenn. I think part of my problem is reading on line and thinking my setup is insufficient, maybe it is, I just don't know. I'm hoping people like you will chime in and tell me if their system is acceptable. I have never run a DC. My shop has wood chips and saw dust all over the place. I'm not looking for "white glove" clean, but I do want to capture most of the dust. If the 2 HP is sufficient then that's great!

    Glad to hear dust in your hanger, DID HE SAY HANGER? LOL is not a problem.

  7. #7
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    Runs 40-45' ft long with lots of ells will not work effectively with a 2 hp 12" or so impeller system. Too much resistence in the pipes and not enough cfm will be moved to make your investment in time and money make sense. Six inch pipe over long runs simply needs more fan capacity. I have runs that long with a 5 hp 15+" impeller and actually run it at 63.5 hz to achieve fully loaded amps. You may find that with your machines a 3 hp 14" impeller might be adequate but that will be as low as you can go and not waste your money. I'm not a Pentz follower but have done enough actual testing of velocity and cfm over pipe sizes and distances to know the numbers. Dave

  8. #8
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    Todd,
    We can all offer opinions, but as they say, "your results may vary". Have you tried using Bill Pentz's Excel based worksheet (staticcalc) to calculate your needs? You will need the fan curve for your machine and your ductwork info (sizes, lengths, bends, etc) what machines you are using and where they are placed. Once you plug all of this into
    his spreadsheet out will pop the answer based upon your situation. As I recall in using his tool I had to decide what level of collection I was after: chip collection, most fines, medical level.

    billpentz.com/woodworking/cyclone/staticcalc.xls

  9. #9
    Hi Todd,

    If you do any searching at all you will find nothing that generates so many threads (and some of them somewhat heated), as dust collection. There are some philosophical aspects, some specific aspects of your exact layout, and some technical aspects (with little common generalized understandings).

    The Bill Pentz site does try to help guide you through these various aspects, while at the same time providing his own views/opinions on the subject.

    So good luck on your decision - here is my experience (so far):


    I had a 2hp bag system that filled my shop with fine dust every time I used it (I limited use to planing and my drum sander). I knew I was inhaling bad dust, so finally decided that yes I should make my health more of a priority and suck it up and do the dust collection. So I thought I could use some of the existing parts and add a cyclone, and do a permanent install and vent to the outside (thinking that I didnt care if it didnt separate great, because in my area I CAN vent to the outside so this is the best way and just let all the little stuff get blown out).

    It just didnt work. Low suction at the tools. I thought about messing around with the ducts and tweaking and trying to get it to work on the ones that put out the most dust, but slowly had to acknowledge that it wasnt going to be adequate. Recommendations of air speed monitors, dust particle counters, pressure gauges, etc to take quantitative data to validate against design calculations had my head (and wallet) spinning (and Im an engineer!!! (or used to be) I have a day job, dont want to spend my hobby doing this crap). So in the end I am going to just add a super giant monster motor/blower to the cyclone and swap some pipes to 6 inch and be done. Then I dont have to worry about upgrading in the future (to add more equipment, or the DC itself). I can know its about as good as it gets in terms of keeping the dust down (and lungs clean - just the other day I cut some MDF on the table saw and can say I was wanting for better DC then).

    For reference, I do subscribe to the philosophy that its the little stuff that is the worst health problem. So that really fine stuff floating around in the air (like every time you shut your car door - if its settling on the cars - isnt good for you. When I was younger I paid no attention to this stuff. Now I do. (age has a way of curbing immortality)

    Another poster recently stated the two things they used most, was their table saw and their dust collector.

  10. #10
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    If you kick up your main horiontal run from 6" to 7" you will reduce your pipe losses, but with PVC you would need to go to 8" which is likely too large for a 2 hp. I have the 2 hp Super Dust Gorilla, my main run is about 30 feet of 7" steel and works fine with my planer at the far end.

    If you put the DC in the garage, will you leave the door open to allow that 1000 cfm back into your shop? Lots of issues with remotely located DC, particularly if you have a furnace.

    If your '08 unit has the HEPA filter, dust in the garage won't be an issue.
    Last edited by Ole Anderson; 03-17-2012 at 10:17 AM.

  11. #11
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    The more marginal the fan HP vs the size of the system, the more dependent it all becomes on getting the details exactly right if it's to work - and even then you'll be pulling the devil by the tail.

    This has all been covered lots of times before, but the key choice is what minimum airspeed you decide to design your system to deliver. There's absolutely no argument about that in industry where dust systems are regulated - it's around 4,000ft/min. Which delivers 785CFM in a 6in duct.

    Bill P sets out the background to these numbers (which he didn't invent) in the page I linked in the post above. The calculator that Carl linked will be based on the same. Cincinatti Fan in their Engineering Data manual (a .pdf download on their site) list 3,700ft/min for 'light shavings', 3,700ft/min for 'sawdust', and 4,500ft/min for 'heavy woodchips'. They don't even list data for transportation of any material for airspeeds below 2,600ft/min.

    One problem with dropping below these numbers is that it leads to an increasing risk of dust accumulating in the ducts leading to fire and other risks.

    It's hard to predict exactly because such small differences in pressure drop make such a big difference to CFM with a small fan like a 2HP when it's heavily loaded like this. Your ducting runs are very long for a system of this size. It's safe to say though that this discussion wouldn't be happening in the context of an industrial system - as a solution it'd be rejected instantly as hopelessly underpowered.

    Depending on how the cards fall in your case you'll probably end up somewhere around 350CFM plus or very likely significantly minus which is very marginal (about 1,900ft/min in a 6in duct - see above on speeds) - depending on how finely tuned the set up and what equipment you are using it may or may not reliably do the basic job of picking up chips. It's certainly not going to be able to reliably handle say a 12in planer in a heavy cut, or do much to help capture fine dust/clean the shop air. Even a slight increase in restriction due to a dirty filter is likely to have very noticeable effects.

    I took a look at the maker's data for the unit you have. They publish a curve, but don't list the impeller size. What I can say though is that I'd need some help to understand how they get a (presumably sustained - nothing else has any useful meaning) 1,349 CFM at 2.3inWG out of a 2HP fan using a BC radial impeller.

    The highest that Cincinatti Fan claim from any low pressure (SPB) impeller and fan combo at 2HP is 1,108CFM, and that's at 1in WG - so low a pressure as to be useless for the sort of dust system we are talking about.

    You're the customer Todd - and it's you that gets to pay your money and make your choice. You're going to have to do the work if you want to make an informed decision on this. There's as Carl suggests though one hell of a pleasure in having a system that does a really good job, protects your health, and does this regardless of the phases of the moon or the wind direction...

    ian
    Last edited by ian maybury; 03-17-2012 at 11:28 AM.

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    Paul, I didn't see the calculator on Bill Pentz' web site I'll check that out. Thanks!
    Sounds like the 2 HP is too small. I have no problem selling it and getting a bigger unit. I'll invest in a 5HP unit. Health matters!
    I could increase my main duct to 7" but then I have to deal with transitions back to 6" PVC. Maybe it's not that big of a deal.
    Yes I will have a means for air to return to the shop, open door or other opening of some kind. My shop is not heated or cooled.

    I appreciate you taking the time to help a fellow wood worker. Lot's of valuable information in all of your posts.

    Thanks to all for your help!
    Last edited by Todd Brewer; 03-17-2012 at 12:44 PM.

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    Todd,

    I didn't want to color my original response to your question, but I also wound up with a 5hp unit (ClearVue). I use a 6" PVC duct system all the way (the CV main inlet is 6" and I have an around the room duct with the run approaching 50'. I'm in a basement with the cyclone in a separate room from my shop. Tremendous pull from the cyclone and very quiet since there is a room separating me from the cyclone. I have severe lung issues so I wanted the best collection I could. I am very pleased.

    Paul

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    Todd, as Paul said, with a 5 hp motor and 6" mains you will still have approx 1000 cfm. You will only be using about 4 of your 5 available hp but unless you have a machine that needs more cfm- 24" planer, edge sander, shaper- you will be fine. When you get to the 3 hp level you need to be careful to maintain enough filter area and limit the bends to keep the cfm up and minimize the resistence. The benefit of the larger motor is you avoid the real testing and run the motor a little under capacity. When you get to the 1200-1500 cfm level you need to watch the components of the 5 hp system to max it out. Dave

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    Quote Originally Posted by ian maybury View Post
    Depending on how the cards fall in your case you'll probably end up somewhere around 350CFM plus or very likely significantly minus which is very marginal (about 1,900ft/min in a 6in duct - see above on speeds) - depending on how finely tuned the set up and what equipment you are using it may or may not reliably do the basic job of picking up chips. It's certainly not going to be able to reliably handle say a 12in planer in a heavy cut, or do much to help capture fine dust/clean the shop air. Even a slight increase in restriction due to a dirty filter is likely to have very noticeable effects.

    I took a look at the maker's data for the unit you have. They publish a curve, but don't list the impeller size. What I can say though is that I'd need some help to understand how they get a (presumably sustained - nothing else has any useful meaning) 1,349 CFM at 2.3inWG out of a 2HP fan using a BC radial impeller.
    ian
    Ian, I am not going to take time to run his system through a pipe analysis, but 350 cfm in a 6" duct with that cyclone, just doesn't seem correct, nor do your conclusions based on that assumption. Oneida's curve shows 8" of suction at 785 cfm with a clean filter in place. http://www.oneida-air.com/Images/Sta...-fan-curve.jpg

    An independent test of that Cyclone by American Woodworker in 2006 was in the same ballpark. http://www.oneida-air.com/PDF/AWW article jan 2006.pdf in fact their test shows the Oneida 3 hp at around 11 inches of suction (static pressure). I was not quickly able to pull up the CV fan curve, if someone would post a reference I would appreciate it.

    At 350 cfm, most cyclones max out their static pressure at 10-15 inches, so at those low flows, you aren't going to see much practical difference between manufacturers, or in fact between models within one manufacturer, it is at the higher flows that the differences become more apparent to the woodworker.

    To look at static pressure at very high flows does not make sense for the typical woodworker with only one large (6") blast gate open, it would make much more sense to compare the static suction numbers from the fan curve at 4000 fpm in a 6" (common size) duct as you have, 785. The result would be a comparison of cyclones at the normal required system flow of 785 cfm. 785 cfm would adequately serve a TS with a 5" bottom and 3" top connection.
    Last edited by Ole Anderson; 03-17-2012 at 3:02 PM.

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