advice on new woodshop: floor + sawdust vac

Looking for advice and expertise for woodshop floor and dust collector. New shop will have concrete slab, and I'm leaning toward embedding 4 or 6" PVC in the floor for dust collector to tablesaw and keeping to minimum overhead clutter, obstructions for dust free as possible. I've read both pro and con on PVC static discharge but have no experiance with it. What about running a bare-wire through it for grounding? If a portable collector works I'm for using one, but I'm trying to visualize manipulating it among the tablesaw, jointer, mitersaw, and belt/disc sander.
Any help is greatly appreciated. [img]/forums/images/icons/grin.gif[/img]

roypat2126

I personally don't have a dust collection system but know a few people that do. I am by no means any kind of expert on anything like this but let me throw a couple things out if I may.
In terms of going through the floor:
By doing so, have you then committed yourself as to the location of all tools as well as shop layout and any future uses for this area?
If you run 4-6" PVC, will it still generate the suction you need? Most I've seen are 3" or less to maintain suction.
To run these pipes, they'll have to be below the concrete itself. Will moisture be an issue and can it clog? Even without moisture, how hard would it be to unclog if it were below ground (as opposed to removing sections above ground)?

The cleanest setup I've seen was to have the main pipe to the vacuum run against the outer wall at approx. equipment height (3-4'). A T is then inserted for each piece of equipment. Run a little sched-40 out, then a valve, then a little more sched 40 and flex pipe to the saw, sander... (setup so the valve can be reached somewhat easily).

You then only open the valve for the machine you're using. He also had the vacuum in a closet to reduce noice (he left it on between machines or cuts to pick up ambient dust).

Hey BC,
Thanks for your reply sorry for taking long to get back, don't have access as much as I would like. And Thanks for your input. I mulled over several concepts and decided on a portable unit that I can roll around to what ever tool. The built in collector is not within budget right now, and I think the portable will work efficiently, can't use but one tool at a time anyway. I like the idea of putting the collector in an enclosed room to cut down on noise. But I would use 45deg ELs instead of ' T 's to not lose any draw power through the tubes.
I'm gettin ready to lay block for starter course of the walls on this project so it'll be a while before I can make sawdust in it. But sooooon.
Much abliged, BC,
roy
roy

You're welcome.
Good luck on the project and post pics.
Brian

My dust collector is a 3HP double-bag Grizzly, I think model 1030. I replaced the stock bags with more efficient felt bags to cut down on the small particles of dust blowing out. I've sent Grizzly an email to determine if I can replace the upper bags with a canister filter that they offer on their later models. I use a remote control with the D/C to turn on/off from anywhere in the shop. I've also built an air cleaner that hangs from the ceiling to clean the very fine dust (using a squirrel-cage blower). Something like this is needed regardless of what you use to catch the main dust and chip flow. I use a Grizzly 1023 cabinet saw, Dewalt 12.5" planer, 6" jointer, Frued router/table with this system along with a 32 gallon trash can and "cyclone" lid to catch the larger chips.

First I'll try to tell you what I did in my shop; then I'll tell you what I wish I'd done...
The shop is 24X40 with 10' ceiling. Like you, I didn't want clutter hanging above, and felt that hose drops from above would be in the way when using my tools. I used 4"PVC for my main collector line down the center of the 40' length. Planned for the dust collector to be at the East end of the shop so I used a wye there to bring the PVC up out of the floor. I extended the PVC from the wye out to the edge of the slab and added a threaded plug for any future "clean-out" requirements. In addition to the outlet for the dust collector there were three for tools down the line, ending with a "sweep-ell". The intermediate outlets were "wye"'s. I ran bare copper wire through the 4" pvc and tied to ground at the dust collector. This ground is tied to a brass bolt in the pvc at the base of each outlet just above the floor, with a wing-nut on the bolt to attach the ground from my flex-hoses to tools. I also ran 220'V in conduit under the slab with an outlet in the floor at each PVC tool drop. Everything works fine.

However, it would be better IF I had used 6" PVC for my main line with my collector. More air flow would improve pickup if using more than one tool drop.
I bought plastic blast gates to open/close air-flow at each tool drop. They're easy to break apart and difficult to repair. I have replacement metal gates on order now.
I've added a 4'X8' room at the East end of my shop (under a drop-shed) and extended my PVC pipe/cleanout so that I can move the dust collector out there along with my air compressor. I will cut the wall between the shop and this room and install two 20"X25" high quality furnace filters to help trap the fine dust particles from air returning into the shop from the D/C room. This project is "ongoing" and I don't know just when I'll finish it, but probably soon, as I'm going to be making about 600bf of hardwood flooring for my houseboat.
I hope this helps.

Here is a good site on the dust collection.

Bill Pentz Cyclone design and various background information