Downdraft sanding table

[Mitchell Andrus]

In my current shop, I've got my downdraft table hooked up to my DC. This is a bit of overkill even with my 2 hp DC and in the new shop running a 3hp cyclone DC for a teaspoonful of dust/minute will be like killing ants with a tank.

For the new shop I'm looking for a design for a downdraft table that will incorporate a self-contained filter system. I've seen a few simple designs that use 20" x 20" furnace hepa filters and a basic window fan. Simple, cheap and - effective?

I wouldn't mind buying a small 1hp single bag unit for beneath the table. I use one on the laser for outside exhaust and it'll be plenty strong.

What have you found to work? Do you know of any design you think might fit the bill but haven't gotten around to building yourself? Money is not a factor.

Also, what do you use for a table-top grid?

I have about 30" x 72" allocated for the overall size of the station but only need about 24" x 30" for the grid area.
.

[Clay Crocker]

This is a downdraft sanding table that I built over ten years ago. It is based on a design that I saw in the December 1997 issue of American Woodworker (#63). I used a squirrel cage fan out of an old central air unit. The cabinet is just pine and 1/4" plywood and the top is made out of poplar and measures approximately 22" X 27". There are actually three furnace filters stacked one on top of the other for catching dust. It works very well because the fan I used moves a lot of air. Since I started using the Festool system for power sanding, about the only time I use the downdraft table is for hand sanding. I guess a larger table would be nice at times, but then it would just take up more space.

Clay
(http://www.sawmillcreek.org/attachment.php?attachmentid=134446&stc=1&d=1260119541)

[Jamie Buxton]

IMHO, sanding tables are obsolete. All modern sanders have dust collection that's very effective. Hook a vacuum to the sander, and suck up the dust as it is being generated.

There are several advantages to the vacuum hooked to the sander. The sandpaper lasts longer. The sander can be used on objects too big to carry to your table -- like almost all furniture. And the vacuum eats less power than the 3 hp DC.

[Mitchell Andrus]

IMHO, sanding tables are obsolete. All modern sanders have dust collection that's very effective. Hook a vacuum to the sander, and suck up the dust as it is being generated.



A good choice for a hobbyist's shop.

I run a comm'l shop and have 9 sanders loaded with different grits/belts at the same time. (Changing paper to change grit size is a waste of paper and time.) Changing a hose to each of these in turn didn't work too well... I used to spend a lot of time fixing cheap clip-on vac tube hook-ups til the downdraft table demonstrated itself to be reliable and non-fussy about the tool being used or the state of repair of the vac connections.

I've yet to see a belt sander's 1" to 1.5" diameter built-in collector work as well as a 400 cfm downdraft table. Many detail sanders and narrow belt sanders have no collector connection at all.

When sanding larger pieces off the table, I do use the tools that have reliable vac hook-ups as you said.
.

[Ed Hazel]

I considered a downdraft table when I put in my 3hp cyclone and ended up just hooking my table to the cyclone, it may be overkill but.
1. I only have one DC to dump-clean with a down draft table you will have filters ect to clean replace.
2. The extra airflow cleans the air in the shop.
3. with a separate table you are going to be running some type of motor anyways so I am not sure the savings would be worth it.

[Mitchell Andrus]

3. with a separate table you are going to be running some type of motor anyways so I am not sure the savings would be worth it.




Sometimes I need to sand for only a minute or two so start/stop cycles on a 3hp cyclone can be a factor. Noise is also a consideration, especially if I can get away with a 1/8 to 1/12 hp fan, like a whole-house 24"-30" size with 1,200 - 1,600 sq in of filters.
.

[george wilson]

I use my Fein vac hooked up to the power tool. However,when I put in my DC,I included a drop of flex hose that lays on my workbench with a gate and a scoop on it with a grillwork on it to keep things from getting sucked up!! I can lay the scoop on the bench near sanding activity if I want to.

[Alan Schaffter]

ROS probably generate the highest levels of fine, dangerous, invisible dust as any machine except other sanders. Though some like Festool have good pickup with a vac attached to the typically tiny 1" to 1-1/2" ports, a seizable amount of fine stuff still gets away. The shopvac's high static pressure and low velocity are not going to get this stuff once it is just a few inches from the tool, so a down draft table is recommended even with tools having a shopvac port. That being said, a down-draft table is only as good as its CFM and the quality of its filters. If the filters aren't good, then you are just recirculating the fine stuff (unfortunately, the same is also true of many shop "air cleaners.")

[Wayne Sparkman]

Mitchell:

Did you say new shop? Will we be hearing more about this (pics?)

[Mitchell Andrus]

Mitchell:

Did you say new shop? Will we be hearing more about this (pics?)

Been posted before, but here's a picasa site of the house and shop my wife and I bought in September. View the visits in order, pre-purchase and then 1 - 4. The shop is about ready but I've got a bunch of tables and storage solutions to build before we can move. It'll be a spring move.

http://picasaweb.google.com/missionfurnishings
.

[Gary McKown]

"what do you use for a table-top grid?"

I made a stand-alone downdraft box of about the size you are thinking, for use with a shopvac. The top was made from a piece of Borg perforated hardboard with a white melamine-like surface, reinforced underneath by a skeleton of ½" wide strips.

It works quite well overall, despite having too many holes for the shopvac port when fully open. Larger pieces effectively close off many of the holes, and for smaller pieces I cover some of them with a sheet of newspaper.

One tip to keep the work anchored - use one of those rubberized router mats between the workpiece and the top.