# dust collection pipe



## Pop (Aug 6, 2007)

I'm designing a dust collection system. Here's my question: I am going to use 4 inch plastic pipe. I find that there are 2 types available. There's "DVW" & there's "S&D". S&D pipe is lighter with a thinner wall than DVW. It also cost less. (About half) Is one type better than another? Does it make any difference? I would prefer to use the lighter pipe just to make installation easier.

Can someone with experience on this give me advice?

Pop


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## MoPower (Feb 6, 2009)

Either will work but be sure to install a grounding system for it. PVC will build up a wicked static charge. I use the metal snap lock duct in mine.


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## SASmith (Mar 22, 2010)

I use 4" S&D pvc to get as close as I can to my machines. Then I use this to make the final hook up. It fits 4" S&D perfectly. I also make my own blast gates using the 4"S&D.


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## BobM001 (Jan 8, 2012)

Hi Pop,

DWV is "Drain Waste and Vent. S&D is "Sanitary and Drainage". The lighter is what I believe they call "foam core". Have you explored that the cost of 5ft sections of 30 gauge 4" metal pipe is? Remember, ALL plastic pipe intalls need to have a bare ground wire pulled through them. Or it is HIGHLY SUGGESTED. Metal doesn't but has to be ground connected at some point. But consider this as well. I just got quotes for metal vs PVC.

I got these prices from a local plumbing and heating supply company I do business with. Go there instead of a big box DIY store. I'll bet the prices will be lower. Get quotes for materials.

4" X 10' foam core PVC $16.61
4" PVC 90 $8.49
4" 26 ga 5' $10.65
4" 26 ga adj 90 $3.25
4" 30 ga 5' $6.54
4" 30 ga adj 90 $2.07

The pipe for PVC may cost less, but the fittings are what kill you. I don't know if 30 gauge pipe will collapse under a vacuum with all the blast gates closed. It might. I doubt that 26 gauge will. Especially 4". Plus with metal 90's you can adjust the angles to whatever you need. Once you get it all installed seal the "gores" with silicone and tape the pipe joints. Plus metal will be lighter than the PVC for install.

The only variable I didn't reasearch is metal blast gates vs PVC. I bet the don't give those away either.

Bob


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## SASmith (Mar 22, 2010)

4 inch pvc S&D 10' at menards $6.49

4 inch 90 degree sewer elbow $2.38

Lowes price on the the pipe is similar but the fittings are cheaper at menards.


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## mrtoasty (Jan 13, 2011)

I don't use anything but the light duty stuff, not sure what it is called. I just went out to the shop and looked and all I could fine is sewer pipe listed on the sections. If you have a problem with static build up in any lines just run a small bare wire through the pipe and ground it to your green wire in any panel or plug. That will take care of it.

Just slip fit the fittings together and run a self tapping screw into them to hold them together. That way you can change as required. The blast gates fit the pipe great.

Les


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## MoPower (Feb 6, 2009)

I use the snap lock ducting that you can get at lowes. I use 6 inch through out and reduce it at the machine. The pvc works very well to but I had trouble findings fittings that would make up on my equipment most of which is 5". With metal ducting i didn't have any problems at all.


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## Pop (Aug 6, 2007)

Thanks Guys,

You told me what I needed to know.

Pop


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## Tomj (Nov 18, 2011)

One thing I want to add is most 4" abs blast gates fit the green S and D astm 3034 pipe with a snug fit. I looked at all the prices comparing sewer and drain PVC and 26 gauge metal duct, in the end it would me cost me about $ 800 dollars to go all out with what I want to do compared to $600 with PVC. In the beginning I was going to go with PVC then I looked at metal duct prices and at first glance seemed not to cost much more and I wouldn't have to glue everything but in the end I realized if I was careful and planned out my system right with the right PVC I wouldn't have to glue it. I want to be able disable this stuff and use it again down the line if I paid $600 overall for it and yes I will ground the system so I don't get shocked. I guess I added a couple of things.


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## Pop (Aug 6, 2007)

Thanks guys, I'm going to use the light S&D pipe and fittings. The static thing is a great debate. According to most of the great writers of books the inside wire does nothing. The ideas include wire inside, outside and any other place you can run a wire to brass screw in the pipe wall at 6 inch to 1 foot intervals The other end of the spectrum is the gentleman from MIT who wrote an article in FINE WOODWORKING with the help of a professor with a PHD in static electricity. They both stated that there was no way in heck a small PVC pipe in a home woodshop was going do do anything but collect dust. After a few detractors told him he was nuts he wrote a 2 or 3 page document with great amounts of math to nail the lid on the subject. Most science folks agree with their conclusion. Your guess is as good as mind.

Pop


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## MoPower (Feb 6, 2009)

He can do all the math he wants, I've been zapped enough times to know that static does build up. Now there has been an argument back and forth as to whether or not that the charge can build up enough to cause a fire or explosion like in a grain elevator. I personally don't think so based on the fact that I have never heard of it happening, and the fact that the ones making the argument that it could happen had never heard of it actually happening. There really is a difference between theory and reality.


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## mrtoasty (Jan 13, 2011)

POP

Scot is right, I have a 26" drum woodmaster sander with a 1500 cfm dust collector. I have 4" pipe ran all the way to the sander. Before I added the wire it would stand your hair on end if you got close. I have a roll of #14 stranded bare wire that I grounded to the sander, ran inside the pipe until it got to the main run, drilled a small hole and brought the bare wire out of the pipe and grounded it to the green lug inside a wall plug. Problem solved! I have since added wire to my planner run and am getting ready to add to the TS run. I would be glad share pictures if you would like.

If they tell it won't work, OK but I just know what works for me.

Good call on the thin pvc pipe. It stretches the hell out of the budget.

If you look at my shop pictures you can see the sander line going up out of the unit.

Les


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## Pop (Aug 6, 2007)

Guys, The guy didn't say there was no static, just not enough to blow the place up or start a fire. There is a difference between a 4 inch shop pipe and a gazillion ton grain elevator.

About the static and the wire inside the pipe. From what I'v found out about this subject over many years is that the problem was eliminated when you nailed the machine to the dust collector. The wire could have been inside the pipe, outside the pipe or hanging from the rafters. It's grounding those 2 things that discharged the static. Yes, Grounding machines to the DC is a good idea and makes for a more pleasant woodshop. Now, if you're going to ground the machines to the DC the most logical way is run the ground wire with the DC pipe. While you're at it, might as well loop it around the pipe or run it inside and err on the side of caution.

Pop


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## woodymays (Jun 10, 2009)

I used sachedule 20 pvc pipe 4" diameter and it work out well. There are fittings that work with the schedule 20. Also, you don't have to glue the sections together either. The sections fit together at close tolerance and you can used the metal worm screw clamps.


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## buffalosean (Feb 15, 2009)

that article, the author states that is is unlikely, and every time he mentions the likelyhood it used terms like "probably" and "unlikely". That is WAY different than saying 'It Could Never Happen".

Dust can ignite. The author says "any such sparks are UNLIKEY to be strong enough to cause ignition." Just because he thinks there can't be an issue, does not make it a new law of physics. Someone who went to MIT is well educated, that does not mean the individual is smart, cognizant of true reality or has any street smarts.


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## Grandpa (Jan 28, 2011)

What I have read about grounding says there has never been a documented case of static causing an explosion in a home workshop. Secondly you cannot ground an insulator so grounding the machine is what we are doing. More precisely I think we are bonding the machines to each other. That is probably the correct terminology. If the plastic and static were a problem then Clear Vue Cyclone collectors would be out of business. I think the REAL problem is the static knock the fire out of people when they get near it. That doesn't feel good even on a good day….right. 
I did read one paper on the subject where the guy thought the best way to take care of this problem was to wrap the pipe in sheets of foil wrap much like we use for cooking. I thought of the industrial or commercial grade since it is about twice the thickness of the other. I wondered if some spray contact cement would work. I don't know but it would be an interesting thing to try.


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## buffalosean (Feb 15, 2009)

if static electricity or sparking is not an issue. I'm wondering why its code for commercial/industrial shops to ground. metal pipe and ground wire is not an extreme price increase for piece of mind.

If theres a chance something can happen, precautions should and must be taken…......

The absence of evidence does not equate to the evidence of absence!!


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## Grandpa (Jan 28, 2011)

Because Industrial units are SO much larger and have more velocity etc etc. Besides the danger is in the shock from the current. The human or any other heart is fired by an electric impulse. If you are shock at exactly the right time….you heart cannot be restarted. CPR is out. Now do you want to run the risk of a shock? that is the question. Still no home fires from dust collectors though.


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## buffalosean (Feb 15, 2009)

also, metal does not burn like PVC…. if god forbid, there was a fire.


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## Grandpa (Jan 28, 2011)

http://home.comcast.net/~rodec/woodworking/articles/DC_myths.html
So can you ground an insulator (PVC pipe is an insulator)


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## buffalosean (Feb 15, 2009)

no. I'm not taking about the shock factor. I'm talking about the spark factor inside the pipe where the dust is. If you feel you don't need to ground PVC…. good for you. I personally would only use metal. The is a forum, and I am just expressing my opinion. Using metal and erring on the side of caution is never a bad thing.

just like I ran my whole house in type L copper. I could have used type M, but I'd rather over-build than under-build. Once again,erring on the side of caution is never a bad thing. If I over do something, I spent more time and money. If I under do it, then I have problems, and the only man to blame is the man in mirror.


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## Grandpa (Jan 28, 2011)

everyone on here seems to agree that you can put it on the outside and bond the machines and the problem goes away.


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## Fuzzy (Jun 25, 2007)

I'm in the "grounding is useless" camp, and I have challenged those of the opposing view to provide valid documentation showing that a dust related explosion has ever happened in a non-commercial shop … this has appeared from time to time on several forums … to date I have not had a single taker.

To support a dust explosion, the concentration of super fine dust must be so dense (inside the ductwork) that you could not see your hand in front of your face … now, I don't make that much combustible sized dust in my shop using any tool that I own. In a commercial shop running several wide belt sanders simultaneously … different situation … they would be far more likely to have conditions conducive to an explosion, although still rare.

If you are in an extremely dry climate and the static pops are annoying you, try running a small humidifier … you will feel better, and it is good for your wood to not let it get too dry. About the only tool where I ever notice any static pops is my planer, and it's not likely to cause me to flinch, sticking my arm in the planer, so, other than being a little uncomfortable, the pops are just a minor nuisance in my shop. Now, I AM in S.E. Tennessee, and low humidity is rarely a problem.


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## Pop (Aug 6, 2007)

The reason the terms "unlikely or not improbable" are use is called CYA. If sometime in the infinite future in a galaxy far away something happened that could in some strange way be linked to static in a home shop the guy would rather not be sued. There's a;ways a attorney out there who will try anything to make a buck.

NOTE: The MYTH BUSTERS tried everything in their power to get an explosion in a DC pipe with no luck. They concluded that the dust explosion in a home shop DC pipe was a MYTH.

Bill "Pop" Golden


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## MrRon (Jul 9, 2009)

I have never heard of an explosion or fire being caused by an un-grounded DC, but Lets say the shop is in a garage where gasoline fumes or other flamable vapors my exist. Is it possible for flamable vapors to be sucked into the DC and if the air to gas ratio is right; BOOM?


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## Pop (Aug 6, 2007)

MrRon, *You better believe it!* The years I spent involved with training at the Charlotte Fire Academy gave me a very healthy respect for both gasoline & propane. We've had a good many fires some deadly, from hot lawn mowers plus gas hot water heaters in a storage shed. Fumes weather in a DC system or just floating around your shop is something you DO NOT want to deal with.

On the subject of DC safety I think the most dangerous thing you can put in a system is a floor sweep. You sweep a piece of metal in, it hits the impeller, the spark falls in the saw dust, smolders an hour or two, and when you're out of the shop the fire starts. Bad news.

Bill "Pop" Golden


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## Visions (Sep 12, 2011)

I agree with Pop 100%.

I have researched the whole static and grounding thing quite a bit, as I am building my own DC system currently, though I have now opted to run spiral-wound galvanized steel piping over PVC as I can get it cheaper than the PVC (through a connection in the HVAC trade). I searched and searched, and I could not find one instance of a fire starting in a home DC system due to a static charge. As well, all the testing done had to use a much stronger spark than can occur in a PVC system to cause ignition, and with a lot more fine dust in the duct than we normally produce through normal woodworking, even with a large drum sander running.

I also talked to several friends who are fire-fighters, and a friend who has a couple degrees to do with electricity and such, and everyone I talked to told me there was much more danger from sucking up a piece of metal, it causing a spark, smoldering in the dust bin and igniting, than there was any danger in static causing me any issue other than a light shock.

You simply can not ground PVC properly as it is an insulator, and you can not ground an insulator. You can ground it enough so that it doesn't shock you, but trying to ground it and the dust inside completely is futile. As well, it is my belief that running wire or other things inside the PVC will be more of a pain in the a-and a clogging hazard than it's truly worth.

If you want to avoid getting shocked, I was given a link to a copper tape with conductive adhesive that looks like it would be easy to run around the exterior of the pipe. You can find it HERE.

If you wanted to get really ambitious, drill a hole every 4" to 6" to glue a copper tack into, and then run the tape over the tacks. This will give you as much grounding as you'll get, and it's easy enough to do.

Good luck.


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## jonmulzer (Feb 7, 2011)

Even if you were to ever get enough of a spark to cause ignition, you will still never reach the Lower Explosive Limit in a home shop. LEL and UEL (Upper Explosive Limit) are very important considerations and the LEL for sawdust or chips is so dense that it becomes an impossibility in a home shop dust collection system. There is just no machine that generates enough dust to reach LEL within the ducts. The relatively low volume and vacuum that a home dust collection setup is able to produce means that the ducts would clog well before you reached explosive limit.

As for smoldering and burning, that is also so improbable as to be impossible. The impeller on a dust collector simply cannot create enough impact force to heat a piece of metal to 500F without completely destroying the dust collector first. You could take any screw, nail, nut or bolt in your shop and place it on an anvil and strike it with a 15lb sledgehammer and you would never reach the temperatures necessary to cause the smoldering that was brought up by floor sweeps, and that sledgehammer would have 100's of times the impact force that a dust collector impeller is able to produce.

Gasoline vapors and other hydrocarbons were brought up also. While technically possible, you would still be in the realm of improbable to the point of being theoretically impossible…...unless you do something REALLY foolish. Ambient fumes in a normal workspace pose no danger. If you were to pour gasoline into a container with a wide opening like a bucket and placed your dust collection hose directly over the surface of it, then you would run a serious risk of explosion. So don't do that. Keep gasoline stored in narrow-necked vessels that are closed but able to burp pressure and you are fine.

The only feasible possibility you would ever have in a home shop where you might have to worry about reaching LEL with a home dust collector would be if you had a 5+ HP wide-belt sander and a 5+HP Cyclonic dust collector. I have my doubts that even a 5HP wide-belt would do it though. I will however guarantee you that you will never even get close to LEL with a table saw, band saw, jointer or planer. It is just not possible.


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## Pop (Aug 6, 2007)

As for the spark in the dust bin. There are many cases of this very thing starting a fire.
As for the fumes. Don't under estimate the explosive power of gasoline. Floors cleaned with gas have leveled houses. Gasoline is heaver than air. It sinks and it travels. It is very slow to dissipate. The response I gave to MrRon was to his question. Gas in the general work place is far worse. All it would take is a near by electric motor.

As for the metal spark. Your force example has a problem. A spark can occur from a hammer striking another piece of steel. You can get a spark from a nail hit at the wrong angle. That impeller is traveling much faster and with considerable more force than a hammer. This is the reason brass hammers are used around explosive environments. The best evidence on this subject is that it has happened (fire reports) and will most likely happen again.

Bill "Pop" Golden


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## jonmulzer (Feb 7, 2011)

I stand by what I said. I did not feel it was necessary to expound on it to include "don't mop your floors with gas". If you have your gasoline in a closed container that is able to vent, the dust collector poses you no issue. If you stick the hose into a bucket of gasoline (who has those just sitting around?), it could explode. If you mop a floor with gas, or aerosolize it with a sprinkler system, it can explode. None of those would be isolated to normal conditions and static electricity discharge within the ducts. Under normal circumstances, it is impossible to reach LEL's within a dust collector.

I also would not fill a fire extinguisher with it. 

You can get a spark from sucking up chunks of magnesium that could ignite your dust collector. That is the only conceivable way I see. If you can link to a fire report that shows someone has ever sucked up a piece of metal with a dust collector and that was the direct cause of the fire, I will rescind my comments. Yes, you can glance off of a nail and cause a spark, that will travel less than an inch in calm air. A dust collector is far from an explosive environment.

You are certainly correct though. If you used a dust collector to vacuum up gasoline mixed with screws, you would be asking for trouble.


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## brtech (May 26, 2010)

There are a lot of threads here about this subject.

The consensus, which is NOT universally held is:
a) S&D is good enough, don't need DWV
b) 26 gauge steel is needed, 30 gauge can collapse. Spiral is better, but mucho $$
c) grounding of PVC is not needed for safety, is helpful for comfort

Also
a) Use Wyes, not Ts
b) Use wide sweep elbows or two 45s and a straight section, not a regular 90 degree elbow
c) Minimize flex; ideally none, certainly less than 10' if you can


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## Grandpa (Jan 28, 2011)

Good summary brtech. This pretty well says it.


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## Pop (Aug 6, 2007)

Amen brtech! When I was designing a DC system for the 1st time. The flow loss from flex and "Ts" was astounding.

Bill "Pop" Golden


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## MrRon (Jul 9, 2009)

With my past experience with shipboard design, everything that could possibly cause ignition, is contained within an explosion proof enclosure when volatile fumes are present. This is strictly enforced in the design process upon U.S. Navy ships. Off course these precautions wouldn't be followed in the home workshop, but you can see, the Navy takes this seriously. Here is an example: A magazine on a Navy ship has a static repellent deck covering, all metals in contact with explosives are non-ferrous [aluminum], all tools are spark proof, ventilation ducts are equipped with fire dampers, lights, motors and controlers are explosion proof.


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## MrRon (Jul 9, 2009)

This discussion has brought up a point that hasn't been mentioned before [as far as I know]. We may be planning for *too* much dust collection. With limited resources, my DC system is designed to handle dust rather than chips. Woodworking machines either generate chips, dust or a combination of the two. Machines that do sanding produces the most dust and should be the major focus of a DC system. Machines that produce mostly chips, like jointers, planers, drilling machines; I don't bother with. A table saw produces large amounts of chips and some dust. In my shop, the sanders and saw will have dust collection; the other machines, no. A full blown DC system is nice to have because it can keep the shop nice and clean, but I don't feel it is really necessary for all machines. As Tomj said, $600 for PVC is better than $800 for metal duct. I would further cut that cost down to cover only the absolutely essential machines, like sanders and saws. I say this coming from an economy point of view. Those with lots of money to burn can go the whole 9 yards.


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## Pop (Aug 6, 2007)

MrRon, I like your observation. The exception to your idea is the jointer & surface plane. While both of these machines produce chips they produce such a great quantity that they require consent removal.. The jointer less so than the surface plane. For the surface plane a DC is a must.

Pop


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## Visions (Sep 12, 2011)

I disagree with MrRon, to a degree. Especially with the planer. A surface planer creates a HUGE amount of waste, and in short order. I know this full well, as my grandfather shop, though very well equipped with some incredible vintage machinery, including a 1930's Unisaw and 16" Powermatic planer, it completely lacks any dust collection.

I do still use his planer often when I purchase large amounts of stock, as I buy from my best-friends grandfather (also who supplied my grandfather years ago) who runs a sam-mill in the same town as my grandfather's shop. On a recent trip, after planing apprx. 20 pine boards from 6" to 10" in width and 8' long, I spent 45 minutes , and maybe longer, sweeping up and carrying six (6) trashcans of chips into the woods. And I was rushing during clean-up, as it was getting dark and making it into the woods was getting difficult.

A simple dust collection system would simplify this a great deal, and make clean-up much easier. Rather than sweeping everything off surrounding benches, tools and floor, I could simply empty a separator trashcan a few times and be done. No other serious clean-up necessary.

In my shop, it is even more of a pain to clean-up should I allow my planer to simply blow chips wherever they land. I have a basement shop that has plenty of stuff in it, and letting the planer just blow shaving all around makes a mess the likes I'd prefer never to deal with again.

If it were me, and my shop was large enough that piping everything to one dust collector was cost prohibitive, I would do my best to buy two or three small collectors and some "5-gallon bucket Shop-vac's", and put collection on everything I could.

And while multiple collectors may sound expensive, it's really not in the grand scheme of things. If you were to buy the smaller 13-gallon collector from Harbor Freight (HERE), you could purchase two for the cost of their larger collector,or 3, 4 or even 5 before reaching the cost of one of the "Big Name" collectors. And by piping them into Thien baffled trashcans, you could have pretty efficient chip collection (and even decent dust collection) for a very reasonable price.

Now add a few "bucket vacs" for smaller machines and those that benefit from higher static pressure, and you have a really nice and complete collection system for a good price compared to a high-dollar collector and a ton of piping.

Before my DC (and even after), I used a few bucket vacs with thien baffled 5-gal. buckets for collection on some smaller machines, like my 8-1/2" miter saw and my Ridgid OSS, and they work well for the $20 a pop I paid for them. And by piping them in with mostly PVC, I retained plenty of flow, and they actually work pretty well with the separators.

Just a thought and alternate point of view.

I understand money can be tight, I know it all too well. But once you see how much easier life is with a good DC, you'll see why people make them a priority.


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## MrRon (Jul 9, 2009)

As I mentioned in my previous post, economy is the driving force in designing my DC system. I only want to deal with fine dust. That is the major health concern. My jointer and planer usage is not very big. My cabinet saw gets the most use and that's where my focus on DC is. I have sanders, but don't use them all that much. My DC system so far has cost me around $200 including the DC, duct and flex duct. I make all my own adapters.


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## Visions (Sep 12, 2011)

MrRon,
I can see the point in economy. And I know that the majority of waste from planers and jointers are large chips, but they do still produce fine dust. So if fines worry you, find a way to move the DC to the other tools or bring the tools to the DC. A mobile DC is a very easy way to spread dust collection around the shop without needing to invest in pipe.

And trust me, I know all too well about financial limitations. The ONLY way I can afford this hobby is by selling 80% of everything I make. And when it comes to making decisions on where to spend in the shop, I think long and hard before I do anything.

If you don't collect from the planer, jointer and other tools, at least run an air filter or wear a good mask.

An awesome and low-cost air filter is a pleated 20" x 20" furnace filter on the back of a 20" box fan. Under $25 total and very effective.

Good luck and stay safe


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