making a downdraft table... questions.


Hi,
I am building a combo work bench/downdraft table. I have some questions. I am working off of the design that rockler sells as a kit. (20" x 40").
http://www.rockler.com/findit.cfm?pagee64&cookietest=1
I was going to just use two 20" square house fans in a blowers stead. I have had some success with a ceiling air filter made with a house fan and some furnace filter. Please keep in mind, I am not looking to suck the hair off my body, just catch some of the dust.
questions:
1) The Rockler motor looks to have some cool impeller of some kind. Is this impeller something like what a vacuum has? Are they sold?
2) could a fan blowing from above, down onto the table help?
3) What is a good material for the surface? (I was going to drill out perfed melamine)
4) I have a 1.5 horse vacuum nearby, I can do better with some fans, can't I?
Thanks!!
Tor
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I have a Ryobi air flotation/down draft tabletop that I bought at a garage sale. Let me see if I can find it on Google. (No luck on finding a picture) It was actually designed to fit on one of their table saws. (BT 3000, I think) The table was new, in the box, but it only came with two legs. Apparently the other side connected to the table saw in some manner. It was no problem to create a couple of legs to make a standalone table. It's really pretty slick. The top is about two feet by four feet, with small holes every square inch. In the middle of the table is a slide mechanism that acts as a gate. The table is made to install a shop-vac, under it, but with a converter, (to take it from two and half to four inches), I was able to connect it to my dust collector with no problem.
BTW, I ran out of room in my shop, and ended up sacrificing the table. I saved the top, with vague plans to possible adapt it as an extension to my Griz table saw....
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Amused wrote:

check http://bt3central.com
There may be a picture there. http://bt3central.com /
I use one on my Ryobi -- it is OK.
willr http://woodwork.pmccl.com
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Does your table have a slide mechanism underneath, that allows you to swing the hose connection back and forth, thus blocking and unblocking suction?
It's actually pretty simple design, but works well.
James..
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1/4" tempered pegboard over a lattice of 1x2.
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I'd make mine with filters inline, your going to want to use a very fine filter for sanding dust, having one or two coarser ones before hand will save some money. Fans wouldn't do this, try a furnace fan or maybe spring for a larger dust collecter and pipe it to any box with holes you decide.
There's a Woodsmith article (Vol 15, Feb 93) with a good design similar to your link. I even scrounged a nice furnice fan with no motor for free, however I never made it as I just made a 4 x 8' box with 1/4" pegboard on one side, 1/2 hardboard on the other, 2x6 frame with holes to each chamber. Sit's on a couple sawhorses. I have a 4 bag 2Hp DC connected. This is also my outfeed table for my tablesaw and bandsaw. I block off areas if I'm doing smaller work. I don't have access to clean it out however and it weighs a ton, make a nice fire when it's time to upgrade.

Don't know, want a furnace fan :)

I wouldn't, you want all the air flow towards the table but too much will blow it away.

1/4 inch pegboard, glue up multiples for whatever thickness you'd like.

Vac's don't do volume well and fans don't like restricted flow (they don't suck) or too fine/too many/clogged filters.
Good luck.
-------------------- Steve Jensen Abbotsford B.C. snipped-for-privacy@canada.mortise.com chopping out the mortise. BBS'ing since 1982 at 300 bps. Surfing along at 19200 bps since 95. WW'ing since 1985 LV Cust #4114
Nothing catchy to say, well maybe..... WAKE UP - There are no GODs you fools!
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