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Trying to set up a dust collection system

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Forum topic by huyz posted 01-18-2016 07:00 PM 692 views 0 times favorited 11 replies Add to Favorites Watch
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huyz

48 posts in 323 days


01-18-2016 07:00 PM

Topic tags/keywords: dc dust collection dust collector dust cyclone air air filter filter

Hey all, I’m trying to set up some kind of dust collection. I currently have a miter saw, a Delta 36-725 table saw, which I assume I can just hook up a DC to without needing mods for better dust collection under the throat plate. Will probably add a band saw, a planer? From reading through the blogs and reviews here, and it seems like there are a few common ways you all are doing this.

1. Shop vac + cyclone
2. A movable DC like Harbor Freight’s 2HP (http://lumberjocks.com/reviews/3431) with an added .5 micron filter. This seems almost like option 1, but with an air filter? Some of you hook this up to a cyclone too. Trying to figure out why and if it’s worth the cost if I don’t already have a cyclone.
3. A central DC with a tube system that hooks up to all your tools. Probably expensive, I’ll pass.
4. An air filter. To remove dust particles in the air while you work, or after you’re done working. This doesn’t seem dust-proof as dust will still get into the air/your lungs before it hits the filter. I’ll probably wear a respirator and have this filter be the last purchase in this system.
5. A dust extractor. Not sure how this differs from the rest.

I’m leaning towards option #2, with a fan in the doorway, garage door open, and wearing a respirator. And just move the DC to whatever tool I’m using. Still worried about sawdust flying everywhere from above the throat plate though. What are you guys using for dust collection here?

Any tips would be great.. thank you!


11 replies so far

View Fred Hargis's profile

Fred Hargis

3932 posts in 1955 days


#1 posted 01-18-2016 07:33 PM

Opinions on these questions will vary a lot, but some basics: #1 and #2 are not the same. There is quite a difference between a vac and a DC. (while I’m here, just quickly; an extractor is a vac with a very expensive price). The DC will moves lots of air, but only with low drag on the system, large ducting, no choke points like 2.5” hoses) and the vac moves small volumes of air at high drag (static pressure) with small hoses and the like. You need both, IMHO. Your statment about the air filter is correct (again, IMHO) that by the time it catches the dust, it’s already in your lungs. That doesn’t mean it’s not needed, just that it’s not needed (as much) for health reasons. Even a world class DC doesn’t catch all the dust, and cleaning the air is a good thing with one of these filters. One other thing: good DC is expensive, though probably less than a lung transplant. OK, on to cyclones. A cyclone is a separator, it removes dust/chips from the air stream before it gets filtered. This, in turn, allows your filters to stay cleaner and allow maximum air flow that enables it to catch all the fine dust particles. It has the disadvantage of adding a lot of drag (SP) to the system and reducing air flow, that’s why most of them have bigger impellers/motors for a given air flow. But they also (usually) make emptying the collected dust/chips easier, and give you more dust bin capacity (the reason for putting them on a vac). All of these are more easily assessed if you determine what you expect from the system. If you want to catch every possible spec of dust and contain, it’s gets fairly expensive fast. If you want to avoid sweeping the floor, it can be done for a whole lot less money. So, where are you on what you want to see from your efforts? Of course, all of this is just my take on it….I’m pretty much closer to “capture and contain every possible spec” end of the stick.

-- Our village hasn't lost it's idiot, he was elected to congress.

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huyz

48 posts in 323 days


#2 posted 01-18-2016 08:04 PM

Fred, thanks for the long reply!

My goal is first, for sure I don’t want dust blowing all over stuff in my garage, reduce sweeping, clean-up etc.

“Capture and contain every possible spec” would be ideal but I don’t think this is possible under.. $500-1000. If everything below the table saw gets sucked up, there’s no point in a super expensive system that traps everything through the DC tube if the top of the table saw is still blowing out dust, right? Or do you have a solution for that :)

View clin's profile

clin

510 posts in 458 days


#3 posted 01-18-2016 08:32 PM

It really comes down to how much you are willing to spend, how much dust you really expose yourself to. I.E., are you in a shop 8 hrs a day, 5 days a week, or an afternoon once a month. And, how much you value your health.

If you can keep the dust level down enough to be healthy, it’s going to be enough to keep your shop clean.

As to your list. #4 is a separate issue from dust collection. A room filter is a way to capture dust that wasn’t collected at the tool. Room filters serve to help keep the shop clean and to help your lungs. Not sure why some say that filtering the room doesn’t help your lungs. A typical room filter will move 1000X or more air than your lungs and will lower the dust level in the air you are breathing.

But I will agree, a room filter does not replace the need for good dust collection at the tool and a respirator.

If you haven’t, go to Bill Pentz’s web site and read up on what he has to say about dust and your health. It’s sobering information.

http://billpentz.com

Bill has lots of general information and points out the benefits of very simple concepts to consider, rather than just assuming you need a DC with fine filters and re-circulating air.

In my case, I run a shop vac (with HEPA filter) and dust deputy (small cyclone) and a Jet room filter. I also wear a good respirator while making cuts and well after.

It works okay for me at the moment. I’m still building out my shop and I’m not necessarily a woodworker. Occasional wood projects, hobbies etc. So it could be that a full blown ducted, DC system is just overkill for me. But, now that I will have a dedicated shop space, I might find I really want to do more wood working and if so, I’d likely install a DC system.


If everything below the table saw gets sucked up, there s no point in a super expensive system that traps everything through the DC tube if the top of the table saw is still blowing out dust, right? Or do you have a solution for that :)

- huyz

You’ll never get it all, but getting even just 50% is better than none. Plus, tools can get clogged up with dust, so sucking out as much as you can from a dust port on a tool is still a good idea. Even with my cyclone and shop vac, I’m collecting 5 gal buckets of dust regularly from my TS (I’m building shop cabinets). Without the shop vac connected to my saw, much of this dust would still be inside the saw and the rest spewing out the back. Even when I can’t use my blade guard and it’s dust port, much more of the dust goes out the bottom than the top.

I’m pretty sure the nature of the way dust comes off a table saw blade is that it is cut, as the blade is going down through the wood, and then getting flung out underneath the table. Also the more you suck off the blade underneath, there’s less that’s going to came back around and get thrown out on top.

-- Clin

View Fred Hargis's profile

Fred Hargis

3932 posts in 1955 days


#4 posted 01-18-2016 09:01 PM

I do have a solution for the dust coming off the blade, an overblade guard that has a dust pickup on it. The one I have isn’t perfect, but it gets probably 90% of the fine stuff. I’ll second clin’s suggestion, go to the Bill Pentz site and do a little perusing. Since there’s enough techno babble there to give most a headache, start with the FAQ section and check out what’s of interest.

-- Our village hasn't lost it's idiot, he was elected to congress.

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huyz

48 posts in 323 days


#5 posted 01-18-2016 09:17 PM


The DC will moves lots of air, but only with low drag on the system, large ducting, no choke points like 2.5” hoses) and the vac moves small volumes of air at high drag (static pressure) with small hoses and the like. You need both, IMHO.

A cyclone is a separator, it removes dust/chips from the air stream before it gets filtered. This, in turn, allows your filters to stay cleaner and allow maximum air flow that enables it to catch all the fine dust particles.

- Fred Hargis

Also if my table saw has a 2.5” output, there’s going to be a choke point even if using a DC right. I see that people are using a DC in combination with a cyclone, but not really seeing how it’s done. Do they both hook up together, then to the table saw?

I did start reading Pentz’ site, and there’s a LOT of info there. Will finish it up. Thanks!

View Fred Hargis's profile

Fred Hargis

3932 posts in 1955 days


#6 posted 01-18-2016 10:29 PM

DC rule #7: Do NOT be constrained by puny factory ports on tools. If you have a good DC and ducting do whatever you can to open those ports up to accommodate your ductwork. Many factory ports are about as useful as, well, nothing. I’ve completely replaced dust hoods (drum sander) and cut holes into panels (band saw) to open them up for better DC. There will be a few cases where there isn’t anything possible, but most of them can be modified fairly easily.

-- Our village hasn't lost it's idiot, he was elected to congress.

View clin's profile

clin

510 posts in 458 days


#7 posted 01-18-2016 10:39 PM


Also if my table saw has a 2.5” output, there s going to be a choke point even if using a DC right. I see that people are using a DC in combination with a cyclone, but not really seeing how it s done. Do they both hook up together, then to the table saw?
- huyz

While the 2.5” port on the tool may be the narrowest point, it’s not the same as running the whole system on 2.5” tubing.

What happens with the narrower openings, tubing, and pipes, is the air speed has to increase. The faster the airspeed, the more resistance to airflow due to the friction with the walls of the pipe. This added resistance creates a larger pressure loading on the vacuum and generally lowers the total flow of air.

Also, as you might image, if transitions from one size to another are not smooth, this creates air drag ultimately increasing the load on the system.

Even if your tool has a small port (2.5”), you would normally still run a large pipe as close to the tool as you can. However, the pipe can be too large. If the pipe is too large for the amount of air being moved, the the air speed will be too low inside the pipe to keep the dust and wood chips moving. In this case the pipe may clog.

As for the DC and cyclone. The cyclone falls into a category called a separator. The air runs from the tool to the cyclone, through the cyclone to the DC impeller (fan). Through the impeller to either a fine filter and back into the room, or through the impeller and outside.

So the cyclone is put in-line between the DC and tool. You’ll find all sorts of YouTube videos showing what they do that will quickly make it clear to you how they are used.

In the end, a good cyclone will catch all the chips and even most of the dust. Then if you are recirculating the air through a fine particle filter, that filter won’t get clogged with the larger particles and wood chips.

I have a small cyclone (Dust Deputy) on my shop vac. It is amazing how well it works. I think when I fill the 5 gal cyclone bucket with dust, I’m not sure a spoonful of dust makes it through the Dust Deputy. It really does work very, very well.

I also use a bag in my shop vac and a HEPA filter. I can’t find any sign of dust on the HEPA filter. Though presumably some very fine dust get through the cyclone and bag. In the end, it’s great to have a shop vac that sucks really well and doesn’t clog. Also, it doesn’t function as a fine dust pump like a typical shop vac does.

-- Clin

View rwe2156's profile

rwe2156

2190 posts in 942 days


#8 posted 01-18-2016 11:16 PM

Haven’t read the posts so I apologize for any redundancy.

You can position the machines very close or else moving the hoses and/or unit around will get old real quick.

I find a shop vac works best for my miter saw, router table and small belt sander.
Shavings producers like a planer or jointer are easy to collect but dust producers like bandsaw, TS, drum sander etc the more CFM’s the better.
.
From what I’ve read, the HF 2HP unit seems to work for a lot of guys. No comparison to a shop vac!!

A ducted system in a garage is probably not warranted just keep in mind flex hose degrades DC performance so you try to keep it to a minimum.

-- Everything is a prototype thats why its one of a kind!!

View JeffP's profile

JeffP

573 posts in 853 days


#9 posted 01-19-2016 12:34 AM

There are, of course, several DC related posts every week, and I find many of them illuminating.

One tree that we seem to forever chase our collective tail around though and can’t seem to get any closer to a solution on…

...if a tool has a 2.5 inch port, are you better off hooking that specific tool to a DC or to a shop vac?

My limited experience so far suggests that those tools (typically low budget “consumer” tools, or mobile tools like a sander or biscuit jointer ) is that tools with smaller ports have smaller entry points for the dust to be pulled in from the tool. With a severe air restriction at the “entry” to the tool, a DC simply doesn’t have enough static pressure to pull any dust through that small system. On the contrary, a shop vac often will be able to suck some of the dust through that limited system, and performs better than a DC.

So, we clearly have some experts out there (Bill, et. al.). So what’s the science say. No doubt they would first say “start by getting a better tool”. Assuming that won’t always be practical…is a restricted tool better with a DC or with a shop vac?????

-- Last week I finally got my $*i# together. Unfortunately, it was in my shop, so I will probably never find it again.

View shipwright's profile

shipwright

7167 posts in 2260 days


#10 posted 01-19-2016 02:12 AM

This is the system I just set up. It is a HF based cyclone type piped in collector but at a lot lower cost than you might think. Your call of course but have a look.
http://lumberjocks.com/shipwright/blog/76186

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fibreglass trees. http://thecanadianschooloffrenchmarquetry.com/

View huyz's profile

huyz

48 posts in 323 days


#11 posted 01-19-2016 09:23 PM

Thanks for the help guys. I read and re-read through lots of the FAQ on Pentz’s site—there’s a dizzying amount of information there but it’s helpful.

Looks like I should get an air quality monitor to see if my setup works and to make it stay efficient over time. I want to keep it cheap since I’m not in the shop every day so will probably work with a fan in the side door & leave the garage door open. This is to avoid needing an air filter… I don’t really see a need to be recirculating air unless it’s super hot or cold outside.

I’m going to start with a good respirator and a cyclone for chip collection. Will use my table saw’s standard dust port for now, and mod if necessary. Still debating if I should use a DC or shop vac for the table saw. If going with a DC, a < 1 micron filter upgrade is probably not needed if I can just fan out the shop until air quality improves right? If using a DC and venting it outside, is a filter even needed?


I also use a bag in my shop vac and a HEPA filter. I can t find any sign of dust on the HEPA filter. Though presumably some very fine dust get through the cyclone and bag. In the end, it s great to have a shop vac that sucks really well and doesn t clog. Also, it doesn t function as a fine dust pump like a typical shop vac does.

- clin

Shop vac, bag, and true HEPA filter seems good too. You could use the vac to clean up any debris missed afterward. Unless the DC is that much better at collecting. I’d still be fanning out the shop during & after working until the air clears.

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