[BBQJoe]

I'm still thinking about my router cabinet; mostly dust collection.
My fence extraction works wonderfully drawing from the end of the fence box. (as compared to those designed in the middle)

Of course some dust is going to fall down through, and those times when we don't use a fence, it's going to go everywhere.
Some folks have under the table collection, usually with a separate hose, which lowers the vacuum pressure.

I haven't seen a system yet where anyone utilizes the other side of the shop vac, the blowing factor.
It seems to me there is an energy source going to waste.
So this comes to mind.

What about running the exhaust port to the router box, then up to the fence, then out to the collection system?
Would this be redundant, would it work better, or would it be completely breaking the laws of physics, dynamic somethings, perpetual motion, and cause the planet to collapse?

Excuse the quick paint program mock up.
(I just realized I forgot to put my dust cyclone on a separate container. Oh well, just imagine it is because I'm not going to draw it again)

 

[difalkner]

Without really thinking about this very much I would think heat would be a big issue. The air coming out of the shop vac is fairly warm and to put that into a closed system I think you'd experience a bit of thermal runaway - the more it runs the hotter it gets. There would likely be other issues but this one alone is enough for me not to try this approach.

David

 

[DesertRatTom]

Consider creating a snorkel to collect clean air that will blow through the router. Dust will still fall into your router box, but it won't get sucked up through and gum up the router. This works if your router has an air intake you can affix the snorkel to. I don't think blowing air in is such a good idea for the reason David cited. Almost everyone has to clean out the containment box from time to time.

I've seen a couple of designs where the dust is extracted from the end of a fence, and it looks like a good thing, so long as the extraction hose is always attached. The stronger the air flow, the more likely the dust will wind up in your DC unit. For that reason, you'll want to make sure there is some sort of air inlet port in your router box. I have a Rockler metal box with a variable opening and opening it just right really helps with the dust collection because of the free air flow.

 

[BBQJoe]

Consider creating a snorkel to collect clean air that will blow through the router. Dust will still fall into your router box, but it won't get sucked up through and gum up the router. This works if your router has an air intake you can affix the snorkel to. I don't think blowing air in is such a good idea for the reason David cited. Almost everyone has to clean out the containment box from time to time.

I've seen a couple of designs where the dust is extracted from the end of a fence, and it looks like a good thing, so long as the extraction hose is always attached. The stronger the air flow, the more likely the dust will wind up in your DC unit. For that reason, you'll want to make sure there is some sort of air inlet port in your router box. I have a Rockler metal box with a variable opening and opening it just right really helps with the dust collection because of the free air flow.

I'm still at the drawing board.
My shop vac is damn near new.
I ran it for a fair amount of time tonight, and surprisingly, the air blowing out from it is just barely warm.
The middle of summer may prove to be a different story.

 

[Rebelwork Woodworking]

Heat catches up as areas become warmer. If your not running your router for extended periods of time it shouldn't be too much of a problem. A lengthy cool down time inbetween may be needed.

 

[Marco]

Let the exhaust go on tapped. Assuming you do not have a large Dust Collector and want the bottom of the table to have dust collection consider adding one more shop vac. The 2nd could handle the bottom of the table. Some will say it is a waste but for me it's not. I have one shop vac excusive to the miter saw with an auto start when the tool is powered on. The 2nd is used for sanding and the Kreg pocket hole jig it also has auto start. The other tools in the shop share one 4" flex house. When that tool is used the 4" flex is connected to it. In your case the 2nd or both shop vacs could be used on other tools in your shop as well as clean up.....