Downdraft Sanding Table/Cabinet?

[Kevin Gerstenecker]

I am interested on building a Downdraft Sanding Cabinet utilizing a Squirrel Cage Blower assembly and filtration. I would like to make the cabinet mobile, so I can easily roll it out of the way when it is not in use. I thought this would also be a good way to filter the shop air of the fine dust that I produce, mostly when sanding on the lathe. One of my 'bestest" SMC Buddies has generously offered a swap of a Squirrel Cage Blower unit for some things I have, and I think this will be a nice addition to my shop. I know I saw plans somewhere for a unit like this, but I cannot for the life of me remember where. Does anyone know of plans available? Or, better yet, has anyone built a unit like this, and if so, what are the things that work great for you, or what would you do different if you were building one today? Any information, such as hole size for the top, baffles, and the like would be greatly appreciated. Thanks in advance for any and all ideas, advice or suggestions! :D

[Dave Malen]

I am interested on building a Downdraft Sanding Cabinet utilizing a Squirrel Cage Blower assembly and filtration. I would like to make the cabinet mobile, so I can easily roll it out of the way when it is not in use. I thought this would also be a good way to filter the shop air of the fine dust that I produce, mostly when sanding on the lathe. One of my 'bestest" SMC Buddies has generously offered a swap of a Squirrel Cage Blower unit for some things I have, and I think this will be a nice addition to my shop. I know I saw plans somewhere for a unit like this, but I cannot for the life of me remember where. Does anyone know of plans available? Or, better yet, has anyone built a unit like this, and if so, what are the things that work great for you, or what would you do different if you were building one today? Any information, such as hole size for the top, baffles, and the like would be greatly appreciated. Thanks in advance for any and all ideas, advice or suggestions! :D

Kevin,
Try Fine Woodworking magazine Issues 153 and 160.

Dave

[Ken Salisbury]

Check Terry Hatfield's web site. I know he built one - maybe it is on his site

[Ron Jones near Indy]

Like I said I have no suggestions, but I do have appropriate questions. I understand the concept involved here. You use the blower to draw air and sanding dust into the table and exhaust the air through filters, thereby trapping the dust in the filter. What type of filter do you plan on using? I've seen these shop made varieties using only a furncae filter. My question is, would using a DC (assuming you have one) bringing the air and dust into a 1 micron bag filter be better in terms of filtering out sanding dust? Furnace filters are not nearly as effective are they? Did you plan on using a different type of filter? Sorry to have so many questions and no answers. :confused:

[Terry Hatfield]

Check Terry Hatfield's web site. I know he built one - maybe it is on his site
I have the build up on my site, but it's cyclone powered not squirrel cage powered.

t

[EliotMason]

Rockler sells a kit for this too - maybe a visit to their webpage or a store will yield some clues. They aslo sell some none-slide goo you can paint the surface with so the belt sander won't launch your panels.

[Martin Shupe]

I think Woodsmith or Shopnotes had a plan for one a while back. It is on my list of things to build, but I am out of room right now. It will have to wait until the new shop in a couple years.

[Noah Alkinburgh]

Kev,

I thought I was your "bestest" SMC buddy :D

I have a set of plans for one in a magazine at home. If I remember correctly it fits everything you have mentioned as what you want it to do. If you want I can try and dig it up and get it to you.

Noah

[Kevin Gerstenecker]

Noah, you ARE one of my Bestest SMC Buddies too..........notice in the thread I said "one of", because I have so many here! :D I have a couple of ideas I have found on the 'Net.......but the more the merrier. I figured the more ideas I have, I can incorporate the best of these to build a very nice unit. Thanks for the offer Noah, that is very kind. If it is not too much trouble, I would like to see the plans that you have too. :)

[Brent Anderson]

Not necessarily detailed plans, but will get you the general idea

http://www.woodworkersworkshop.com/plansshare/air_filter_downdraft_sanding_table.htm

[Dan Stuewe]

My question is, would using a DC (assuming you have one) bringing the air and dust into a 1 micron bag filter be better in terms of filtering out sanding dust? Furnace filters are not nearly as effective are they? Did you plan on using a different type of filter? Sorry to have so many questions and no answers. :confused:

Ron,

I think those 3M Filtrete are pretty comparable to a 1 micron bag. They're available all over the place. I put two in my over head air cleaner with a washable one taking out the biggest stuff (three total filters). I like the way it works, but I'm also concidering converting it too a down draft table, not because I have more room than I know what to do with, but because it could also be a work surface.

[Ron Jones near Indy]

Ron,

I think those 3M Filtrete are pretty comparable to a 1 micron bag. They're available all over the place. I put two in my over head air cleaner with a washable one taking out the biggest stuff (three total filters). I like the way it works, but I'm also concidering converting it too a down draft table, not because I have more room than I know what to do with, but because it could also be a work surface.


Thanks Dan. I'll check out the 3M Filtrete next time I'm at the borg.

[Kevin Gerstenecker]

Dan pretty much nailed what my thought was on the Downdraft Sanding Table Ron. There are very good filters available now, and getting filtering capacity equal to the 1 micron bags on my DC unit is possible. I am building this unit for several reasons: First, to further clean the air in my shop, and to give me a good collection area in which to sand. Second, it will double as an outfeed table for my TS, which will be a nice addition, and third, because I just want to build one. I plan on using a 2 stage filter system.................installing double filters to further the filtering capacity, and to help the 3M Filtrete filters last a little longer, as they will be used for the final filtration. There may be some "trial and error" things to try to get everything just right, but that is half of the fun of undertaking a project such as this. I will let everyone know how things go when I get the unit up and running. I have a few paying jobs to get out of the way first...........but I plan on getting on this as soon as I can.

[Ron Jones near Indy]

Dan pretty much nailed what my thought was on the Downdraft Sanding Table Ron. There are very good filters available now, and getting filtering capacity equal to the 1 micron bags on my DC unit is possible. I am building this unit for several reasons: First, to further clean the air in my shop, and to give me a good collection area in which to sand. Second, it will double as an outfeed table for my TS, which will be a nice addition, and third, because I just want to build one. I plan on using a 2 stage filter system.................installing double filters to further the filtering capacity, and to help the 3M Filtrete filters last a little longer, as they will be used for the final filtration. There may be some "trial and error" things to try to get everything just right, but that is half of the fun of undertaking a project such as this. I will let everyone know how things go when I get the unit up and running. I have a few paying jobs to get out of the way first...........but I plan on getting on this as soon as I can.


You convinced me Kevin. This goes near the top of my to do list. Right after a good work bench to replace the junk one I now use. :)

[Kevin Gerstenecker]

I'll keep ya posted on the project Ron.............if I run across anything significant, I will let ya know. I have some good information I have scrounged up, and I have a few ideas of my own...........as well as ideas and help from the Creeksters..........should be a nice project, and welcome addition. ;)

[John Preston]

Like I said I have no suggestions, but I do have appropriate questions. I understand the concept involved here. You use the blower to draw air and sanding dust into the table and exhaust the air through filters, thereby trapping the dust in the filter. What type of filter do you plan on using? I've seen these shop made varieties using only a furncae filter. My question is, would using a DC (assuming you have one) bringing the air and dust into a 1 micron bag filter be better in terms of filtering out sanding dust? Furnace filters are not nearly as effective are they? Did you plan on using a different type of filter? Sorry to have so many questions and no answers. :confused:

Ron,

The question is partly of horsepower. A DC sucking 900 CFM is probably a 2 hp motor pulling about 8-10 amps of 220v juice. A furnace fan is 1/3 horse draws an amp of 110 and can push 1500 CFM or more. The furnace filters available now are excellent, just check out the selection at your local Wally World or Box store.
The rest of the equation is that most DCs do not filter nearly as well as an air cleaner. That fabled 1 micron filtration is with what is referred to as a dust cake lining the walls of the bag. That dust cake helps filter the air, and also decreases the volume of air the DC moves considerably.
My air cleaner (same filtration principle as a downdraft sander) uses three different filters and should clean the air better than my cartridge filter on my DC.

Regards,
John

[Ron Jones near Indy]

Ron,

The question is partly of horsepower. A DC sucking 900 CFM is probably a 2 hp motor pulling about 8-10 amps of 220v juice. A furnace fan is 1/3 horse draws an amp of 110 and can push 1500 CFM or more. The furnace filters available now are excellent, just check out the selection at your local Wally World or Box store.
The rest of the equation is that most DCs do not filter nearly as well as an air cleaner. That fabled 1 micron filtration is with what is referred to as a dust cake lining the walls of the bag. That dust cake helps filter the air, and also decreases the volume of air the DC moves considerably.
My air cleaner (same filtration principle as a downdraft sander) uses three different filters and should clean the air better than my cartridge filter on my DC.

Regards,
John

Thanks John,
Then that also explains why many feel a 2 micron filter on a DC is actutally better than 1 micron bags doesn't it?

[Paul Kunkel]

Kevin, I built one w/ a 1500 cfm blower and think I have the plans here somewhere. I'll look for you. I couldn't get along without mine, it sucks not only the dust but acts as a hold down for panels as well.
Found the plans- Badger Pond. The link still shows on my computer, but I can't post it here. I'll try some screen shots when I have time and I'll send you the link by email

[John Guerra]

Hello Kevin,

I've been lerking on this site for a while but think this is my first post. Anyways, Woodmagazine featured a nice side draft sanding table that uses a swirl cage unit. Check out issue #133 - you can see it here:
http://www.woodmagazine.com/woodmag/133/images/workbench-lg.jpg

Also Wood featured another one that was an overhead unit that used a swirl cage, you might be able to get some ideas from it. It is issue 120 (Winter/99).

John

[Chad Pater]

I have question about the fan size. I have a small squirrel cage fan from a cloths dryer that blows a lot of air but is too small for this. (right?) How do you know the cfm's, is it on the furnace (if that is where you got it)?

[Kevin Gerstenecker]

Chad, I would think you would want to be up around 800 CFM or higher to really have the Downdraft Table to it's job effectively. I am not sure, but I would think that a fan out of a clothes dryer would not move enough air to be effective. Most of the squirrel cage blower units I have seen will have the CFM rating on a tag on the unit. Yes, most of the Squirrel Cage blowers are from furnaces.........at least that is where most of them come from that I have seen. The one I am using did come from a furnace. Check with any HVAC Contractor, they just might have one laying around they will give you.........or at least have an old Forced Air Furnace in the junk pile that you can get one out of.

[Garry Smith]

This might give you some ideas. I built on something like you are thinking about. I leave mine running most of the time I am in the shop just to keep the air cleaner and it seems to help alot. Check it out at

http://www.superwoodworks.com/Projects/SandingBench.htm

If you have any questions, my email addess link is on every page on my site.

Garry

[Joe Scarfo]

I've been wanting to build one of these. I picked up the squirrel cage from the neighbor when he replaced his AC. It's a 3 speed 220v unit.

LOML is on me to deliver it to the curb, along w/ my super kewl fire hydrant. I just can't part w/ either....

Patience, it'll get built.

Good Luck w/ your pjct.

Joe in Tampa....

[Dave Avery]

Kevin,

Nice to see you back posting. Hope all is well. Dave.

[Jack Wood]

This is not a great pic of the one I built but if you want I can post better ones. I used a 220v blower with a filtrete final filter and two regular fiberglass filters as prefilters. I have placed it by my DC system and what ever gets by it gets sucked in to the filter. It's on wheels so I can move it around if I need to. I am going to make a sanding table that will sit on top of the unit when I need to sand something. Though that's on the back burner as I have a downdraft sanding box built into my work bench that uses the DC to pull air through it and it works really well for most small jobs, but the modification of my big filter would be better for the big stuff. I also have built a ceilng mounted filter using a leftover gable fan that works really well also. Be prepared to have a lot of people warn you about the dangers of Air Filters and how you shouldn't use them but have a large volume cyclone DC instead. Well I couldn't afford the huge price of a national brand cyclone DC so I used what I have and feel the more filtration of any type is a good thing. Good luck!:D

[Kenneth Reidy]

Hi Kevin,

I believe that a down draft table/air cleaner combo seems to be a beneficial addition to any shop. Could you please keep me in the loop? I have been searching for plans for a squirrel cage unit but have not found a link that works or that I like. Any input would be appreciated.

Ken

[John Lifer]

Shopnotes 103 had a pretty good looking one powered by Dust collector.... Could motify...
Another one as outfeed table...http://www.whitemountdesign.com/DowndraftTable.htm

[Bruce Wrenn]

LOML is on me to deliver it to the curb, along w/ my super kewl fire hydrant. I just can't part w/ either....

Patience, it'll get built.

Good Luck w/ your pjct.

Joe in Tampa....Get a dog, and you can justify the fire hydrant. Can't say the same bout the blower though.

[james glenn]

I built one that doubles as an outfeed for my TS. It was one of my first projects, and I built it a little over size (in my go
big or go home phase) but it also works as an assembly table. I based it loosely off of the link Brent posted above
http://www.woodworkersworkshop.com/p...ding_table.htm (http://www.woodworkersworkshop.com/p...ding_table.htm)

I have a few outlets in it as well to plug a sander, router, saw, etc.. in while using the downdraft.
The furnace filters, as someone mentioned above, work better than the DC bags. And I doubled them up
to be sure and catch all I can. The squirrel cage pulls so much air this isn't an issue.

I have a few bad pics of mine, but can get more if you want to see.

A few suggestions:

1. provide easy access to the filters for cleaning and changing.
2. plan your hole locations and size well ( I drilled 1" holes at 3" apart, I think, but now have to
go back and use the router to make a groove for the dust to travel to the holes in. My holes
are slightly too far apart it seems
3. make the tops removable in the event something falls in.
4. use the space underneath for drawers/storage.
5. plan the vent location well. it will blow any dust on the floor into the air and aroung the shop.
6. make some sort of "clamping rail" or prodive locations for pipe clamps to attach. I have some escuchens (don't know how to spell)
that the pipe can screw into on one end and use the clamp on the other. This combines with a clamp block that has
some dowels to fit your hole size.

If you have any questions, ask. I can get pictures of mine to better explain, but it's buried under a pile of tools right now.
All I have is this picture of the frame.

Jimmy181357

[Joe Angrisani]

John wrote: "....The question is partly of horsepower. A DC sucking 900 CFM is probably a 2 hp motor pulling about 8-10 amps of 220v juice. A furnace fan is 1/3 horse draws an amp of 110 and can push 1500 CFM or more...."
"""""""""""""""""""""""""""""""""""""""""""""""""
What am I missing here? Why don't we use furnace motors/squirrelcages to pull through our cyclones? Does the fine dust wipe out the squirrel cage efficiency quickly if it's before the filter?

[Roger Eihausen]

181364
here is one I built years ago

[richard poitras]

Have you looked on Craigslist lately? I see them now and then for reasonable prices. I just picked up a Denray down draft table. Model # 2634B that sells new for about $2000 for $250.00.

Richard
http://images.craigslist.org/3p23o03l65Y65U65P1b1ka402730640b7107a.jpghttp://images.craigslist.org/3ma3od3l25Y65Q05R4b1k522f5cb5afbc141a.jpg


(http://www.wwthayer.com/Denray-Cartridge-Down-Draft-Table-2634B.asp)

[Josiah Bartlett]

John wrote: "....The question is partly of horsepower. A DC sucking 900 CFM is probably a 2 hp motor pulling about 8-10 amps of 220v juice. A furnace fan is 1/3 horse draws an amp of 110 and can push 1500 CFM or more...."
"""""""""""""""""""""""""""""""""""""""""""""""""
What am I missing here? Why don't we use furnace motors/squirrelcages to pull through our cyclones? Does the fine dust wipe out the squirrel cage efficiency quickly if it's before the filter?

The squirrel cage blower can only move that much CFM if it doesn't have any restriction on the input or output, and squirrel cages won't be able to pull much of a vacuum. Dust collector blowers are designed to be able to suck all that air through a 6" hose and out through a filter.

[hank dekeyser]

I "threw one together" last week that connects to my cyclone. It doesn't work all that great so I revamped it to use my summer blower (squirrel cage) and it is quite an improvement. Now if only I had built it big enough the first time. I pretty much just made a criss-cross of 11x2's I had left over and put some sides on it w/ a bottom. problem was, the scraps I had dictated the size I made. Oh well, keep in mind to be sure whatever yo ubuild that it is larger than the largest panel you plan on sanding on it. I didnt bother w/ drilling holes in a sheet simply because I figured the criss-cross would make more sense and allow better airflow. I use anti slip / sanding pad stuff on it and have a few scrap pieces of 1/4" ply I use to "shorten" the table / block off the excess openings depending on size of piece I'm sanding. After all you only need to draw air on the perimeter of the workpiece for it to be effective, and all the holes in the middle are pretty useless since the workpiece covers them anyway. Dug an old DC bag out of the trash and made my own pleated filter. So far so good BUT it will be upgraded when I find the time. I'll be sure to post pics when it happens

Couple things I thought of already

table size
filter accesibility
speed controller (I have a 4 speed motor on mine)
larger bottom to allow a larger filter
Difuser/collector, so ALL the dust doesnt have to go through the filter
output baffle/ difuser

[Mike Cruz]

Kevin, do you mean a unit like this? I'm actually selling mine. You're a little far away, though...:D