[Jim-Iowa]

I too have one in the works. It won`t be pretty but should work fine.
I took a 24 X42" 1/4 pegboard panel. Drilled all holes out to 1/2". mounted it to 1x1 frame of pine.
second frame same material with metal lathe cover to hold filters.
The box 26X43 x30 on 5" casters is 7/16" OS board(Had it on hand) and am mounting a furnace fan for air flow.

 

[Jim-Iowa]

Stan I think your right I'll put my shop vac air purifier down on my work bench next time I'm sanding to see if that helps. Thanks

If I`m getting this right, your using the 1 1/2" hose on your vacum ?
I would definately use the 2 1/2" if you have it.
And did you say you did not have a bottom on it?
Sealing the bottom would concentrate the suction to the box.
You did not mention how many holes and what size you used?
Since the vacum has good velocity but low volume, I really have no clue how many holes of what size it would handle. I know my Bt3100 , router table and CMS work pretty well with the 2 1/2 on my bigger vacum, the small one I have never hooked to a machine yet. I only use it to clean benches.

Don`t give up on this idea too soon, you may have to go back to the drawingboard a few times. But it is a worthy project to pursue.
After gagging and coughing up MDf dust for a week, I`m regretting not getting my sanding table done more quickly.

I took the 1/4" pegboard holes out to 1/2" and countersunk them.
I may have to go to 3/4", some guys using the HVAC blowers report whistling with not enough or too small holes.

 

[Jim-Iowa]

Reliable Thats good information! I tend to be more of hack and try type.
But we can all do with some math help.
They idea of using the standard size holes in the pegboard sounds great.

 

[Jim-Iowa]

Glenmore: If you have it you might want to tack in some flashing tin(or aluminum) on the corners.
I`m wondering if the 90 degree angles in a box would cause turbulence and leave dust in the corners? Just an inch up and an inch or two across the bottom and the sander vibration would cause the dust to move towards the center where the vacume could pick it up.
I think cutting the box down is a good idea, it will give the vacum less chance to lose velocity.