Negative Pressure Box

I know lots of folks have made full enclosures for their various Shapeoko sizes, but all the ones I’ve seen use a shopvac on a dustboot and a follower hose. Has anybody tried a negative-pressure space? Put a high CFM dust collector at the back of the enclosure, then put a brushed slit across the front of the machine? I’m sure it wouldn’t collect large chips as efficiently, but I wonder if it’s control of fine dust would be better?
Thoughts? I’m going to be building a cap for my CNC table, might give this a whirl if my dust boot is a flop.

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Thats what I’m planning to do with mine, using a recycled dryer blower.
Planning to attach to the frame maybe, and leave the gaps in the bottom.
The router fan keeps the work pretty clear, and I have a lot of space (a retired poultry house).
I also have bad lungs, so it’s still an issue.
I wear masks right now.

I’ve been thinking along this line, too, because I simply do not want a big honkin hose on the front of my spindle. My thought was to have a full width vent at the back of the S03 attached to a shop air cleaner and then have an air hose from a compressor attached to the spindle to blow the chips and sawdust out of the cutting path. Of course, I’ve made absolutely no progress on this because I always find other things that need to be done.

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I spent a few hours tonight leveling my sup wasteboard and… well, a few hours standing with my dc hose right against the spindle and only catch 80% of the mdf dust. I’ve got to get a lid on this thing. Going to be drilling holes for work holding and don’t want to play the hose game.

I’ve got an extra 3/4hp DC motor/impeller. I’m going to mount it and its bag under the cabinet, rout the hose up the back to a long slot at the back, level with the table. Then when the cap goes on, I’ll put another long slit with brushes along the front. At the least it should keep the fine dust down, at best I’m hoping for an air skirt across the top of the work area. Will be building this week and will report back.

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My 2c worth. Not so sure about how successful the idea is. True you will remove much of the dust etc but. The router/spindle throws swarf in all directions. Dust will deposit and buildup in the corners of the enclosure regardless of how much vacuum you pull through.

I employ a dust collection box around the router in my router table and this is exactly what happens.

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I can see where that would happen, Patrick. I’m not under any illusions that this would collect MORE volume of particulate than a dedicated boot. I’m ok with having to vac out the case after each run. I’m more interested in containing the super-fine dust that I think a boot would miss. We’ll see. I’ll make the box high enough that if this is a major failure, I can still strap on a boot and hose. Thanks for the input!!

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A 100-cfm to 150-cfm shopvac is going to evacuate all the air inside your enclosure multiple times each minute.

The finest dust, that dust which stays airborne, won’t stand a chance whether the air is being evacuated through a hole on a boot, or through a port on the back of your machine (setting up your machine as a sort of laminar flow system). Either method (boot or exhaust port at the back of the machine) will get the fines (technically, the boot will work better).

What you will be missing w/o a boot is the chips. The chips will have enough weight that they will simply fall somewhere and stay there until vacuumed.

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