I have the Shapeoko 3 unit with a 18.75 cu ft cabinet and 2 doors. If I were to reverse (blow air into the cabinet) a bathroom exhaust fan 50 cfm into the top of the cabinet and have a 2" x 10" open grille at lower back would this move enough air for the router to work effectively?
Thanks in advance,George
At one time I thought that the airflow from the router could be used for cooling the endmill / clearing chips, and worried over it interfering with the vacuum — then I tested the airflow. A vacuum can fill/empty a garbage bag quite quickly, while it’s a long tedious count waiting for a trim router to do that. So long as there is some sort of fresh airflow into the enclosure (say through a set of baffles) it will be fine.
The one thing to not do is to vent the vacuum into the enclosure creating a closed loop which will continually heat the air and recirculate particles which the filtration missed.
A series of baffles, and/or a pair of hoses through a window (one for the intake into the enclosure, one for the outtake from the vacuum) would be perfect.
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Hi Will, so do you think my idea would be ok? or should I use the exhaust fan on the top to suck the air out instead of blowing in and the open grille at the lower rear would bring in new air be better? I am trying not to break the bank and use this exhaust fan I have.
Thanks again, George
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George,you haven’t mentioned dust control at all. Just venting doesn’t keep the dust down. It just moved it around, where it will eventually collect in the dead zones and perhaps in your lungs.
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I will have the Sweepy system on the Dewalt and a rigid 4.25 hp shop vac for dust collection.
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The fan should only move clean air — so it should blow fresh air in — unless you work up a filtration system.
I don’t think it’s necessary or helpful if you have good dust collection — and you need dust collection, ideally with a cyclone system to save your filters.
Some folks find the Dustopper works well — it can be paired w/ quite inexpensive vacuums (if one can stand the racket) or one can easily make a cyclone (I did one of a bucket and some PVC plumbing fixtures). A quiet vacuum is a huge quality-of-life improvement for using the machine. The high-end option would be a Festool CT Midi w/ an Oneida Ultimate Dust Deputy.
Thank you so much Will for your input and time
I have the Dust Deputy Deluxe Anti-Static Cyclone on the rigid vac . So If I have the fan blow air in from the top of the cabinet and the vacuum system on I should be OK as far as heat and air moving in the cabinet on long milling jobs (not burning up the router and Carbide 3D control panel). Should I still have the 2 inch x 10 inch open grille on lower back or is that needed?
George
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You need enough of an opening to let air in — a slight negative pressure for the enclosure is good for dust control — I like the idea of a baffle to reduce noise.
Check the output port and cooling vents on the vacuum itself — I’d go for an opening with a bit less surface area than those twain.
Your vacuum will suck out a lot more than 50 cfm - likely 150cfm. That would render the fan redundant. Just a vent would suffice to allow air in while the vac sucks it out.
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Thank you Ben, I have a 2 inch x 10 inch grille I was going to put on back of the cabinet. Would it be best to put grille high or low on the back?
Air takes the path of least resistance. So if your input is high put your exhaust low. The air will make a straight line but eddy currents will move air in other areas. The other areas won’t get the same cfm but will move air. One thing to consider is hot air rises. In a small space this is not significant but helpful and any help is good. Plus you don’t want to spray sawdust all over your shop so gravity will help sawdust stay in the cabinet with air from bottom to top movement.
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A closed loop would be quiet though…so maybe we just need to added a little intercooler (heat exchanger) and a better filter right?
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I’m wondering what that heat exchanger would look like. There is always dust coming out of the exhaust that would accumulate over time and need to be cleaned out.
What about an external “exhaust pipe” serpentine loop that takes the heat outside of the box and returns the exhaust (and noise) back to the inside? Kind of like the air compressor heat exchangers made of copper pipe and mounted to a wall.
Oh, and a “glass pack” muffler, too (or two!) 
ADDED: I never thought to look for this stuff on Amazon before.
ADDED: Glass Pack Muffler
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What about a liquid cooling loop? Radiator inside the enclosure to soak up heat, radiator outside the enclosure to radiate it away, pump moving liquid between the two.
Air transfer of heat to metal isn’t very good so I doubt the radiator inside would do much to keep the temperature down without a big radiator and a lot of airflow over it. My personal setup is an enclosure for the shapeoko with the vacuum out, the vacuum is also enclosed separately and that box has a 8in fan reduced to a 4in hose that vents outside. The shapeoko enclosure gets warm but nothing I’d really worry about. The vaccum enclosure is more of an issue and the 8in fan barely keeps it under control.
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Yeah… “My shapeoko has two 36 inch cherry bombs”…
If you want to use a closed loop for air circulation, bleed some of the air out from the filtered/high pressure side. That will cause the system to bring in fresh ambient temp air to the supply.
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