# dust collection



## Rob G (May 11, 2014)

I'm planning out my dc system and I need some help. I have a small 2 car garage with a basic tool setup. Table saw, miter saw, planer, jointer, band saw etc. I'm not sure what size pipe to use. I'm using pvc to keep cost down and I already know about grounding it. I don't understand all the cfm stuff I've read online. My buddy is a hvac journeyman and he told me to use 4 inch everywhere cause 6 inch will cause a loss in suction in the system but that contradicts everything I've read. I also should note that I will never have more than one machine running at a time. Any suggestions. Thanks, Rob


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## Fred Hargis (Apr 28, 2012)

Your buddy is partly correct. With a smaller DC, using 6" pipe will be a problem. It's not so much a lose of suction as it is a slower air flow. That combo will have have such a slow air flow particles may drop out of the air stream leading to clogs. But if you have a large DC (call it 2+ HP), putting a 4" duct on it will be wasting money, that DC can pull much more air than the 4" duct will allow. In all this, you didn't mention what you will have for a DC....which is a key part. Now, for the "CFM stuff", air flow is important...good DC requires moving huge amounts of air. One well known fellow suggests 1000 CFM at the tool to capture it all. No problem for a 1300 CFM DC, huh? Not exactly, DC CFM numbers are mostly fiction, about as accurate as the 6.5 HP your shop vac has. A rule of thumb_ might_ be to figure they deliver about 1/2 what they claim; though I suspect that's being overly generous. Much simpler to just plan for the biggest DC you can work into your space/budget/other constraints and go from there. In all this don't forget the filtration...a DC with 30 micron filtration (usually bags) is no better than a big dust pump, putting the dangerous stuff right back into the air, and your lungs. I suggest 1 micron or tighter for filtration. Lastly, "you know about grounding". What exactly is that you know? It's unneeded and a terrible complication when you makes changes to the system in the future....besides costing money. You know, but I'll mention it anyway, all this is my opinion. But you can read some good stuff at the Bill Pentz site; start with FAQ, there is a mind numbing amount of techno babble there and you want to get to some of the basics early on.


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## NetDoc (Aug 6, 2013)

Interesting read. Thanks.


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## mobilepaul (Nov 8, 2012)

Fred Hargis said:


> Your buddy is partly correct. With a smaller DC, using 6" pipe will be a problem. It's not so much a lose of suction as it is a slower air flow. That combo will have have such a slow air flow particles may drop out of the air stream leading to clogs. But if you have a large DC (call it 2+ HP), putting a 4" duct on it will be wasting money, that DC can pull much more air than the 4" duct will allow. In all this, you didn't mention what you will have for a DC....which is a key part. Now, for the "CFM stuff", air flow is important...good DC requires moving huge amounts of air. One well known fellow suggests 1000 CFM at the tool to capture it all. No problem for a 1300 CFM DC, huh? Not exactly, DC CFM numbers are mostly fiction, about as accurate as the 6.5 HP your shop vac has. A rule of thumb_ might_ be to figure they deliver about 1/2 what they claim; though I suspect that's being overly generous. Much simpler to just plan for the biggest DC you can work into your space/budget/other constraints and go from there. In all this don't forget the filtration...a DC with 30 micron filtration (usually bags) is no better than a big dust pump, putting the dangerous stuff right back into the air, and your lungs. I suggest 1 micron or tighter for filtration. Lastly, "you know about grounding". What exactly is that you know? It's unneeded and a terrible complication when you makes changes to the system in the future....besides costing money. You know, but I'll mention it anyway, all this is my opinion. But you can read some good stuff at the Bill Pentz site; start with FAQ, there is a mind numbing amount of techno babble there and you want to get to some of the basics early on.


Couldn't agree more on everything said by Fred! Additionally, if you can vent to the outside, the better the inside air will remain. If you cannot, the better filter you need. Look hard at the Wynn Environmental filters. If you have any doubts about which one, call them, they are very helpful. Bill Pentz, lately, has been updating his site, beginning with the cyclone testing pages. I assume we should see updates in most categories as time permits.


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## woodnthings (Jan 24, 2009)

*A dust collector is an air pump ....*

So is an automobile engine. Everyone is always concerned with the intake side until they realize all that air has to escape also... Hedman headers anyone? As the dust collects on the bag surface, 2 things happen. The flow is reduced, but the filtration is increased. Canister filters have way more area, so they are preferred, but also more expensive.

The Pentz site is brain numbing, as Fred says but if you can glean the basics, you will be better off. Impeller size and speed are big factors for extracting every smallest particle and keeping it airborne until it reaches the separator or filter. The CFM ratings are "mystery" stats and there is no standard of reference that I know of, maybe someone does? So, the basics say get a bigger system than you think you'll need as losses in pipes and tubing and bends all add up. 

The Harbor Freight 2 HP is a favorite all over the net and here at WWT since it can be purchased for $150.00 or even less. Then you replace the 30 micron bag which will stop the larger insects and stuff with a 1 micron or even a .5 micron bag or a Wynn canister filter.

Blast gates at each tool are preferred by some, others just move the DC around on it's dolly up to the machine in use. That's my approach. This save running piping overhead and drop and all the other stuff. 


I have the Jet 1 1/2 HP systems with remotes and they are the greatest. Remote are so handy that I wouldn't want to be without one. You can also use a heavy duty switch box on a heavy duty cord to remotely turn the DC on or off. Another DC I have has this type with a magnet on the switch box which I just slap on the machine's cabinet I'm about to use.
Read the dust collection forum here, it will take a few weeks, but you will learn a lot. :yes:


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## mobilepaul (Nov 8, 2012)

I apologize for the mixup, Bill Pentz updated the cyclone measurement section most recently, not the testing section...


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## Rob G (May 11, 2014)

Fred, thanks for all your insight. To answer your questions and I think someone else mentioned this also, I'm going with the 2 how model at harbor freight but I will be upgrading to a better filter probably a Winn (did I spell that right) and adding a seperator. As far as the grounding, I plan on wrapping the pipe with grounding wire and at various junctions installing bayonets so if I need to add or just do a clean out I can just unplug the grounding wire. I was thinking with this system I would use 6 inch for my main lines at 4 inch to each tool. Is this accurate.


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## Rob G (May 11, 2014)

Also I think I read that the ground wire needs to be sort of bonded for lack of a better word to the pipe at each junction with a 1/2 in. screw and loop connector but I'm not sure if I understood that right. I'm just concerned about static building up. My wife is against spending money on the system(I know. Don't get me started) so I'm trying to make it as safe as possible. So beleive me, she is the google queen so if someone on the internet says its necessary then she will beleive that it is.


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## mobilepaul (Nov 8, 2012)

Rob G said:


> Also I think I read that the ground wire needs to be sort of bonded for lack of a better word to the pipe at each junction with a 1/2 in. screw and loop connector but I'm not sure if I understood that right. I'm just concerned about static building up. My wife is against spending money on the system(I know. Don't get me started) so I'm trying to make it as safe as possible. So beleive me, she is the google queen so if someone on the internet says its necessary then she will beleive that it is.


well, if she needs to read something, have her read what Bill Pentz has to say about grounding....


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## Fred Hargis (Apr 28, 2012)

I've not had first hand experience with the HF DC. I have read many folks have used 6" duct with it and seem to be happy. My guess is it's on the edge of not being adequate for 6", but that's only a guess. The grounding might offer some comfort from static shock (or not), but it's easier to just avoid touching the ducting. The thing is it doesn't do anything for safety (physical injury/property damage) just personal comfort. (Side note, if you talk on the cell while you get shocked I suppose it's possible the phone might be damaged...or I Pod...or I Pad). Back to the ducting, if you read Pentz i think you'll find that having large duct and choking it down just gives you the air flow at the choke point, in other words running 6" and then going down to 4" at the tools gives you 4" of air flow. So why not just run 4" all the way? This does give you more static pressure (resistance to flow) than the 6" but will be far less likely to clog because you will have a higher ait velocity in the duct. BTW, when you price the ducting, especially the 6", look at the cost of the fittings...that right there might drive you to 4". Forgot to add: be sure to look up Thein Seperator, having on of them will make life a little nicer.


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## Marv (Nov 30, 2008)

Here's a dust collector comparison that includes the HF (Central Machinery)

www.portercable.com/uploads/PCD/Documents/News/182DustCollectors.pdf


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## Rob G (May 11, 2014)

Fred, you the man. Thanks for your advise.


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## Jeff5254 (2 mo ago)

I have a PM1300, I built a cyclone separator from shop notes. it worked for years with a wood Teck I inherited from my dad's shop. It did not work very well when i tried it in my 2nd shop that had 10 foot walls. I bought the plan from Onida air systems that had a 5-inch main. Now in my 3rd shop. 8- foot ceilings 20X24. should I plan on 5-inch mains with 4-inch lateral Ts at 4 machines. Plan on long radius elbows at the 4 drops. plan on all metal pipes excluding hook up to each machine. Or should I make it all 4 -inch? and will there be any advantage to mounting a motor on my separator?


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## B Coll (Nov 2, 2019)

Rob G said:


> I'm planning out my dc system and I need some help. I have a small 2 car garage with a basic tool setup. Table saw, miter saw, planer, jointer, band saw etc. I'm not sure what size pipe to use. I'm using pvc to keep cost down and I already know about grounding it. I don't understand all the cfm stuff I've read online. My buddy is a hvac journeyman and he told me to use 4 inch everywhere cause 6 inch will cause a loss in suction in the system but that contradicts everything I've read. I also should note that I will never have more than one machine running at a time. Any suggestions. Thanks, Rob


Your in a small shop in your garage. I am sure you are somewhat limited. Here is what I have learned. I use 4" PVC. Unless you are running a commercial operation everything I have read indicates that static problems are a non-issue, which has been my experience. I would take the time to layout your piping. I have a good size shop with 10' ceilings and a concrete floor, so I ran my piping on the ceiling with drops for each machine. I have also found that the quality of the blast gates you use, especially with smaller DC's is very important. Get metal blast gates and the best quality you can afford. My DC is a cheapo 1 1/4hp that I have had for over 20 years, It runs my cabinet saw, band saw, RAS, spindle shaper and jointer flawlessly. I have a 15" stationary planer which will bog it down from time to time if I am doing long runs of wide widths, but it does not happen that often. I also use a cheap cyclone lid on a 30 gal. garbage can as a chip collector. This has served me well over the years and doing custom furniture pieces to complete kitchen cabs. If I were to purchase a new one I would go for 2hp only for the sake of the planer.


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