Dust Collection: length of hoses on 350+ cfm unit

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djscruggs
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Posts: 41
Joined: Tue Jul 16, 2019 9:33 am

Dust Collection: length of hoses on 350+ cfm unit

Post by djscruggs »

So, this forum has convinced me to go with a high cfm unit instead of an adapted shopvac for my small woodshop. I'm now trying to figure out space. I have the option of placing the dust collector on the other side of a cinderblock wall in a 6 foot high, dirt floored crawl space. (Note, my workshop space is tiny....Its only about 7 feet wide and about 20 feet long). Mostly, I use this space for turning wood. For larger projects, I do the rough cutting in my carport, the glueing and finishing in the finished room outside of my workshop area....the workshop is where I do final cuts, turning wood, sanding, etc.

I'm wondering, though, about the distance AND direction that dust would have to travel. Let's assume I get the equivalent of Harbor Freight's smaller dust collector with 660 CFM.

1) I have a hole in the cinderblock wall that is 5 feet off the floor of the workshop. If I put the dust collector on the dirt floor of the crawl space, the main hose would go up 4 feet, and then back down 5 feet to reach the floor of the workshop. The hose would need to be even longerto attach to several different pieces of equipment. At what length does the hose become too long to do what's needed? I would use a shopvac for regular clean up but the dust collector for dust.

2) A second option would be to build a mount on the crawl space side of the wall such that the dust collector is located basically 5 feet off the floor at the same level as the existing hole in the wall. This means that the hose, when connected to my shop smith would only have a 2 foot upward angle, and I'd probably want the flexibility to extend that hose about 8 feet to accomodate the shopsmith and a few other smaller machines.

3) A third option is to cut an additional hole in the cinder block wall specifically to run the hose through at the level of the crawlspace floor. I'd prefer not to go this route, simply because I"ve never cut a hole in an existing cinder block wall, but, like everything, that's just because I don't know how to do it.

Thanks again for your guidance....I have already learned a ton about dust collection from this forum!
bainin
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Location: NC

Re: Dust Collection: length of hoses on 350+ cfm unit

Post by bainin »

I wont give guidance, but I will tell you what worked for me..hopefully something useful can be gleaned from it for your application.

I have a Jet 650CFM unit with about 10-12 feet of 4" flex tube terminating on the tool with a 3 or 4 inch long , 2.5" diameter hose for quick disconnect/reconnect on the various ports on the tool.

This works fine for me..havent observed any clogs/poor suction. For table saw, router, jointer, band saw use. The Jet unit is just off camera on right of pic.

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Of course, a min/max vacuum guy would tell you :

1) Shortest possible run between pump and port
2) Hard tubing rather than flex with biggest diameter possible
3) Avoid sharp bends

I intend at some point to upgrade to hard tube, but as I haven't seen an issue with this config, I've been lazy to move forward.

b
br549
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Location: Midway between Houston/Galveston, TX

Re: Dust Collection: length of hoses on 350+ cfm unit

Post by br549 »

I can't give any real suggestions on your question, but in following your questions in your previous thread and this one, I have to wonder about putting any dust collector on the crawl space side of the concrete wall. Won't access for changing / emptying the bag be a problem? How will you turn it on or off - just by plugging or unplugging it? Won't a crawl space be damper than the basement itself, and maybe cause the dust collector to rust more quickly? If the crawl space is under your first floor, won't the noise travel more easily to your house? Can you put a gyp. bd. ceiling in your shop area (with sound insulation) to help control noise getting into first floor above?

Looking at the two models Harbor Freight sells, I couldn't find any dimensions, but the footprint for the smaller unit (with bag sideways) looks like it may take as much floor space as the larger model.
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Have you made a sketch of your workshop with your equipment (all drawn to scale) so that you can experiment with placement? Having the dust collector in the shop area, or just on the fringe of the shop in your storage area, would seem better to me.
Is there enough headroom in the shop area to utilize the space above the smaller dust collector so that it could be more accessible, if it is put in the shop area and not the crawl space?
sehast
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Location: Milpitas, CA

Re: Dust Collection: length of hoses on 350+ cfm unit

Post by sehast »

Probably not telling you anything you don't already know but the longer the hose the more the performance will degrade. So even though your shop is small and dust collection requirements are modest I would go with a larger CFM collector if your budget permits. Then you don't have to worry so much about hose runs. That being said bends in the hose usually cost you more in performance than straight runs so try to minimize them or keep them to slight gradual angles. And as has already been said go with a 4" hose to as close as possible to the collection point. If you are pretty much set on the dust collector you are going to buy, then get it and do some experimentation with different hose runs to see how much margin you are going to have.
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