dcsimg

Vacuum VS Dust Collectors??

Viewing 20 posts - 1 through 20 (of 54 total)
  • Author
    Posts
  • #271069
    thedude306
    Moderator
    Foam Lake, SK

    I want to thank to Pros for bringing this up:



    @overanalyze



    @Toolshead

    A dust collector like that works so much better than a vac does for use on table saws, router tables, planers, jointers, etc. A good vac is still better on a miter saw, track saw, sanders etc.

    Don’t forget the difference between the vac and the DC – one is lots of flow, the other lots of (negative) pressure.

    I have to be honest, I don’t know when to use one over the the other. I know that the Vac is big suction, low volume and that the dust collector is big volume and low suction.

    When I contacted a DC vendor for use as a vacuum they highly recommend against it. And outside of sanding and source dust collection (router, Js) the vacuum doesn’t cut it as a dust collector.

    My bosch vac is 150 cfm with 97″ of water suction.
    My general DC is 1550 CFM with 11 1/4” of water suction

    Quite the difference on both ends of the spectrum!

    So my take is that things with big dust clouds or high volumes of dust use the dust collector. Things like the table saw and the planer/jointer.

    But then I got thinking about it, why not on a router? Or a sander? They create a lot of dust? Same with the miter saw? But you never see (or rarely perhaps) see dust collectors on these tools. It’s almost always vacuums. Same goes for DC on concrete equipment. That’s a HUGE dust maker and they always got to a vacuum.

    I’d like to get your scoop on when and why the difference?

    Brad T
    Self employed Pro since 2014!!

    #271077
    crotalusco
    Pro
    west bend, wi

    I dont see why you couldnt hose down a DC to do mobile tool collection if you were using your blast gates properly. A boom arm as well. The only thing i can think of would be drag on the machine as it may not move enough air trough the small hose. Love putting your hand over the end of a vac hose.

    Even then you could eliminate that some. A router table at least can have a fence and a machine hose, The sanders could have the hose and down draft and so on. That or open a blast gate on a stationary tool some

    Portability is the main reason to have a vacuum

    #271080
    kurt@welkerhomes.com
    Moderator
    Owatonna, MN - Minnesota

    I think a lot depends on where you are using the tools. In a dedicated shop, I see most everything hooked up to a dust collector. The high volume that it pulls will handle a table saw, miter box and router table just fine. If you are looking for localized dust collection such as on a jobsite or when using a handheld router or tracksaw, then the vac would be best.

    The collection method may be different on a miter box with the different methods. A vac would go right to the port on the saw, but a dust collector would probably be hooked up to a hood on a stationary saw. The dust collector for sanding would probably be better on a downdraft table than on the sander itself.

    Concrete by itself is a whole different animal. Typically you are not grinding, cutting or drilling concrete in a shop where you would have a stationary dust collector so the portability of the vac would dictate its use. Also weight of the particles to size would be more for concrete so I would think the higher velocity air would be better at retaining the particles than the higher volume.

    Reducing the hose on the dust collector would create a higher velocity air stream which would help in some cases but it could also starve the DC and cause it to overheat.

    #271094

    I think a lot depends on where you are using the tools. In a dedicated shop, I see most everything hooked up to a dust collector. The high volume that it pulls will handle a table saw, miter box and router table just fine. If you are looking for localized dust collection such as on a jobsite or when using a handheld router or tracksaw, then the vac would be best.

    The collection method may be different on a miter box with the different methods. A vac would go right to the port on the saw, but a dust collector would probably be hooked up to a hood on a stationary saw. The dust collector for sanding would probably be better on a downdraft table than on the sander itself.

    Concrete by itself is a whole different animal. Typically you are not grinding, cutting or drilling concrete in a shop where you would have a stationary dust collector so the portability of the vac would dictate its use. Also weight of the particles to size would be more for concrete so I would think the higher velocity air would be better at retaining the particles than the higher volume.

    Reducing the hose on the dust collector would create a higher velocity air stream which would help in some cases but it could also starve the DC and cause it to overheat.

    So is that why when I use my Kapex my midi DC works better with the 50mm or the Bosch 35mm hose as opposed to the 27mm?. When I use my TS55 I use the 27mm as well as on my router and Carvex. The 27mm works perfect on these guys.

    #271129
    staker
    Pro

    In my book a vacuum is for cleaning and a dust collector is for collecting the dust and shavings for machines.

    #271169
    woodman_412
    Moderator

    A lot of it has to do with the size of the port and collection area on the tool. Portable tools such as mitre saws, sanders, routers etc tend to have small collection ports and the area where the dust is created is smaller so they need higher velocity more concentrated suction to effectively collect the dust. Bigger machines like tablesaws, thickness planers, jointers etc have big ports and produce high volumes of chips and dust that need a big volume of air movement to match.

    The reason that it doesn’t work well to hook up a portable power tool to a big dust collector is that when you step down say a 4″ line to a 1 1/2″ line you get the air moving at pretty much the same velocity(which is much lower compared to a vacuum) but lose the volume so you have now lost the advantage of that system. Air moving through a small port at big port velocity just isn’t enough to give good collection. The same goes the other way if you use a vac hooked up to a 4″ port. The velocity of that air will drop considerably once you step from the vac sized hose to a 4″ line and since it’s a vac you don’t have volume on your side either.

    One rule of thumb that I read awhile back about dust collection systems is that at dust collector pressures air will not be compressed. So basically the smallest diameter pipe or hose in your system will be your limiting factor. Air will not compress and speed up when you step down the line in size, it will just limit the volume and velocity for the whole system. I found that to be very helpful when designing a dust collection system so I just thought I would throw that in there as a side note.

    Dan

    danpattison.com

    #271239

    Dan nailed it!! Excellent explanation! You will love using a dust collector on a table saw or your planer Brad. I think even the router table will work well using the DC over the vac.

    Andrew

    A Working Pro since 1995!

    Member since March 26, 2014.

    #271254

    Good information @woodman412 . Thanks for the post .

    Always willing to learn .

    #271417
    thedude306
    Moderator
    Foam Lake, SK

    Yup, so I was doing some experimenting tonight and this is what I found, and it kinda makes sense.

    It has to do with the machine and dust collection set up of that machine… Trying to use the shop vac on a a large volume collector like the table saw or planer just doesn’t work. Same goes for using the DC on a small high velocity collector like the miter saw or sander, it’s useless.

    The vacuum doesn’t create enough flow on a 4″ hose. Like almost none. Barely sticks to a board.

    Same goes for the dust collector. It doesn’t make suction on the 32mm hose. Like almost none. You can here the impeller cavitating try to produce vacuum.

    My router table was designed for a 4″ hose on the bottom side and a 2.5″ on top. I bought one of those 4″ – 2.5″ y so I am hoping that works OK. If not I will put the DC on the bottom and the vac on top.

    I am going to do the same with the table saw. I am going to add a plate on the bottom with a 4″ hole and use a Y to the 2.5″ hole on the back side of the blade.

    I am glad I am going to have both in the shop. And I have learned a lot on DC over the last two days. The biggest being I am going to add a cyclone and having a filtered room to put the DC machine in for the new shop is a must, for both noise and dust in the air.

    Brad T
    Self employed Pro since 2014!!

    #271425
    theamcguy
    Pro
    Fayetteville, NC

    Great post Dan. Thank you for the explanation.

    Automotive Pro
    Fayetteville, NC

    #271439
    Toolshead
    Pro
    In the Rice Fields, South TX

    Lots of good explanations above. Being kind of simple, I think of it as ‘clean out nooks and crannies – vacuum with crevice tool, lots of stuff already moving in the same general direction – DC’.

    In my shop, everything except the grinder (sparks) is hooked to the DC – RAS/shaper: chute behind blade, router table: top through fence and bottom behind bit, bandsaw through port, table saw through port, scroll saw through sealed riser box underneath, drill press through box underneath, stationary belt sander through port, sanding table through box underneath, and hand power tools through their ports and 2″ hose. Everything connects through hose to 4″ hard pipe (should have gone with 6″ for main line…) to a chip separator to the DC.

    Keeping the dust suspended in moving air is key to good extraction and avoiding clogs. Every layout differs. I find that sometimes cracking open a gate midway helps get more air in and keep dust moving where otherwise it may fall out.

    To continue with the line of what @woodman_412 said, if you are sucking a large cavity where there’s not a focused flowpath, any extraction will be more difficult. An example is underneath a router table. My tabletop is relatively dust-free where the dust goes through the fence. Where dust drops into the cabinet I get lots of build up. If I remember to crack the door open, then more air can get in and more dust gets sucked out. If I went to 4″ below, or isolated the router into small cavity under the table, it would probably solve the problem. I can’t see where much dust at all would get collected from beneath saw table mounted router. There’s just too much free air space to focus flow (it would likely fall onto the floor instead of into the motor, though).

    FWIW- the bandsaw DC port is 2″ metal with a spider (*). Rip cuts that leave stringy ‘dust’ quickly clog it. The hacksaw will come out some day to cure it.

    Some folks do use the DC as a vacuum. You sweep the floor into a big pile and open a gate to a port at floor level. It’s more of a dust pan than a vac. I don’t just because I want to protect the impeller from any hardware that may have been gravity assisted. That’s also the reason for the chip collector. Some people use one of the many cyclones out there. I have a big box with a labyrinth inside
    hanging on the wall next to the DC in a small room next to the shop. It’s made of scrap T111 screwed together and caulked.

    I started out with a big Shopvac and a trash can separator and moved it from tool to tool. I spent more time cleaning out filters than woodworking. Since the vac was pretty much always drawing on a sealed system, that motor didn’t last long.

    And I still use a leaf blower to push what’s left out the door. πŸ˜‰

    #271440
    woodman_412
    Moderator

    No problem guys. I’ve learned a lot about dust collection over the years both from reading and from trial and error. I used to have a 4″ dust collector hooked up to a 2 1/2″ system in my first basement shop. The system ran around the whole shop to every machine. I quickly learned that it didn’t work well and ended up taking the system out eventually. I’ve learned from mistakes like that over the years.

    When I got my Super Dust Deputy last year for my dust collector I did a bunch of reading on the physics of dust collection and the science behind it which I found a huge help. I designed and built a new dust collection system in the shop that I worked at after we moved last year and it worked really well. The line that came off the dust collector was 8″ and then I stepped it down as it got further away from the collector. I put into practice the science that I had learned and it paid off with great performance.

    Dan

    danpattison.com

    #271718
    Anonymous
    Inactive

    Gee whiz, This all makes me a little dizzy. Thanks Dan for the splainin, That helped a lot. I had no idea stepping down a DC would make it suck less, I do understand how stepping up with a vac to say like a 4″ hose would make it suck less…It’s all very confusing though, For me and my uses rather than having both I think I’ll stick with a 2 1/2″ hose on a vac and step it down where I have to and hope for good enough..Thanks guys

    #271719
    Anonymous
    Inactive

    When I got my Super Dust Deputy last year for my dust collector I did a bunch of reading on the physics of dust collection and the science behind it which I found a huge help.

    Ooooops forgot to say, And of course I’m going to build a Dust Deputy for a vac. Those things are awesome

    #271728
    thedude306
    Moderator
    Foam Lake, SK

    yup, the dust deputy is pretty nice.

    I am glad I have both systems now.

    Brad T
    Self employed Pro since 2014!!

    #271803

    Interesting thread Brad. Basically, it sounds like you are gonna force me to get a dedicated dust collector once I get into larger machinery. Grrrrrrr. πŸ™‚

    Thanks for explaining it so clearly Dan

    John S

    #271815
    thedude306
    Moderator
    Foam Lake, SK

    It’s not just large stuff. I used it on my router table today. Dust free routing. And it’s going to be great with a downdraft for a built in miter saw.

    you need one. It’s light and portable and moves around.

    πŸ˜‰

    Brad T
    Self employed Pro since 2014!!

    #271859
    woodman_412
    Moderator

    I have the Dust Deputy on both my vac and my dust collector and they are excellent. It really transforms the performance of both of them making them much more efficient and easier to empty. One of the cool things about the plastic Dust Deputy for the vacs is they are clear so you can see exactly how much dust you are collecting and watch it swirl. I was noticing that today when I was using my track saw and saw how much dust was getting collected.

    Dan

    danpattison.com

    #271897
    staker
    Pro

    With my planer I added a drop box and it works great, had one for the 6″ jointer to but it doesn’t work with the 12″ jointer. Helps on not filling up the 35 gallon barrel to quickly. Make sure everything is grounded don’t want a fire starting. I heard some guys think its BS but no need to take a chance.

    #272330
    Anonymous
    Inactive

    yup, the dust deputy is pretty nice.

    I am glad I have both systems now.

    Yep having both covers it all, It actually worked out for the better πŸ™‚

Viewing 20 posts - 1 through 20 (of 54 total)
  • You must be logged in to reply to this topic.
© Robert Bosch Tool Corporation 2014, all rights reserved.
queries. 0.374 seconds