Advise on sanding table

[Larry Conely]

I'm interested in making a sanding table to a specific size, roughly 24" x 48". The thought has occurred to me to use pegboard for the top section and hook it up to my dust collector with a 4" connection. Having never used one of these tables, I have no concept of how large the holes can be before one looses downdraft. Any experience with this?

Thanks for your time,

Larry

[Jim Becker]

I'm certainly no expert on this, Larry, but the "best" designs I've seen incorporate a stepped design under the perforated table to insure that the air flow from a blower reaches all the holes in the table somewhat evenly. They also generally have their own blower source and filters, rather than hook to a DC. (Folks often use old HVAC blowers to build these things...kinda like building an air filtration system, but with a surface you can put your goods to sand)

[Jim W. White]

As to Jim's comments. Here's a link to one I threw together a couple of years ago.

http://myweb.cableone.net/jimnbeck/downdraft.htm

[Jim Becker]

Jim, that's a Really nice one! Great job.

Do you have any problem with, umm...small things...disappearing into those holes? (I'm thinking not of when sanding, but when the downdraft table is just sitting there and you inadvertently set something down on it...)

[Terry Hatfield]

Larry,

I built this one a couple of years ago. It's along the lines of what you are describing....

<IMG SRC="http://www.fluiddt.com/terry/dd_box1.jpg">

I have a complete build page here.....

www.fluiddt.com/terry/dd_table.html

Not sure if 4" would be enough to power a table that big. The 6" does fine with my cyclone. The performance of this type of sanding box is really as much about the collector as it is the box.

Hope that helps,

Terry

[Alan Schaffter]

One thing to consider which I haven't seen taken into account in most sanding tables is that except for using suction as a hold-down if you place your object to be sanded in the middle of the table you are covering suction holes- so why have them in the middle in the first place. If I were to make one, I'd vary the hole size- small ones in the middle and large ones to the outside. You want max flow- furnace fans flow CFM but have almost zippo static pressure.

[Jim W. White]

Do you have any problem with, umm...small things...disappearing into those holes?

Thanks.

I have a sheet of plywood cut to size to rest on the top when using it simply for assembly; BUT, yes, I have found some things when blowing out the filters that I didn't know had disappeared. :p