dust collection

You will get a lot of opinions on this, but you will find that most people end up using PVC just for it’s cost and availabilty. I have a 1000 SQ FT shop and I actually ran my 4” PVC pipe below the concrete slab.

According for an article in Fine Woodworking (Issue 153 page 48), it’s not necessary to run a ground wire if your DC is 3HP or less.

I also use the Long Ranger to control it.

-- Gary, East TX -- The longest journey begins with a single step.

I am also using 4” flex pipe with my DC system. It is definitely not very efficient. The ribs on the inside of the pipe cause turbulence in the air stream and a lot of the chips and dust fall out of the stream on the way to the collector.

When I set up a new shop after our next move I will probably use metal pipe. If I was to use PVC to save on costs, I would do something to try to ground the system. I’m not so much worried about sparks causing explosions or fires, I just really hate getting stung by static electric shocks. I get them all the time when using the shopvac with my RAS. It’s terrible during the winter months.

-- Mark

I’ve got the standard 3hp grizzly with 30 micron bags housed in a closet with standard air filters venting back into the shop. I used standard 6”, 5” and 4” metal duct work connected with selftapping screws and sealed with metal duct tape. I already had some sheet metal crimpers, cutters and other tools so it wasn’t a big deal for me. The worst thing about cutting and working with metal duct work is the danger of cutting yourself, so gloves are an asset. The Grizzly Tools catalog has a pretty good little tutorial on duct work sizing etc.

-- Carl Rast, Pelion, SC

Jeff, I agree with Gary and with Mark. I will be using PVC in mine for cost but using some sort of ground just to keep the static down. Not worried about explosions, but I noticed yesterday just how many time I got shocked from it. That gets annoying fast.

My shop is also 1,000sf. I haven’t decided whether to run all 4” or do a 6” main with 4” branches. I’ll only have one tool on at a time, so I’d be interested in other opinions on that too.

-- Kevin, Wichita, Kansas

Pvc is nice, but very exspensive. You will have to order all the fitting as no one carries 6” fittings for it. Plus it does not come in odd sizes like 5”. Me, I use standard stove pipe. I can get it locally and the fittings for the most part are cheaper and easier to find. Many hvac places will make or order you hoods or fittings to match your needs. For the metal fittings in my new shop wil be spiral pipe. The fitting are not prone to leaks like standard stove fittings.

I have been using 4” rain gutter pvc and could not be happier. It is much cheaper than sch 40 or sch 80 pvc and works with all the fittings.

-- Rob McCune

Al—are you talking about sched 40 PVC, which is expensive?

6” and 4” Sewer and Drain PVC (Sched 20 or ASTM3034 as I used), however, is relatively cheap. The only fittings that I could find locally cheaper was the metal 30ga. stuff which is too thin for DC work from what I’ve read. I got the 6” stuff at Menards, which I don’t believe they have in TN, but I’m told that plumbing supply houses stock the stuff and Lowes can order it, I believe. The 4” stuff is available at HD and Lowes.

Personally, I recommend the “green” ASTM3034—not as attractive as the white stuff, but it makes a much snugger friction fit with the fittings than the white sched 20.

-- Patrick, Chicago, IL www.TenonAndSpline.com

Has anybody tried running bare copper wire on the outside of the runs and grounding the wire to what ever is handiest?
I have this task to do this summer and have been thinking about the PVC alternatives too with transiitons to metal sweeps at the gates and nearer the cyclone.

Bob

-- A mind, like a home, is furnished by its owner

The sewer grade pvc pipe it self is not costly. It is the fittings for it that cost big bucks. 4” pipe is to small and restricts the flow.

It’s about 1/6th the price of steel economy piping and 1/11th the price of premium steel piping made just for dust collection. At least going by the prices from Penn State.

I seem to remember getting a PVC “Y” fitting for about $3.50 and an economy steel one costs $28.95.

That doesn’t seem all that expensive to me. Also 4” seems to work fine for me.

-- Gary, East TX -- The longest journey begins with a single step.

Here’s a link to the page on dust collection in the Grizzly Catalog on their website. When I posted above, I didn’t realize they had the whole catalog online. Dust Collection. This is pretty good “starter info” for a dust collection system.
Like I said earlier, I used regular home hvac ductwork from the big box store. Unless you’ve got a gonzo 10 hp cyclone pulling 5000 cfm or more, I beg to differ about it being too thin for dc applications. The only drawback is that where the fittings connect and are crimped to make a “male” end to mate up with the “female end”, often the metal sticks up some and may stiffle the flow just a hair. That being said, you can still use metal duct work and use the plastic fittings (wyes, tees, 90’s, reducers) that are meant for the corrugated dc hose. They fit perfectly snug inside the metal duct. Metal duct tape will seal her up pretty dang tightly. Although as GaryK said, FWW magazine says you don’t need ground wires for DC systems 3 hp and less, if it would make you feel better, screw in a ground wire across the plastic fitting to ground the metal parts to each other and to the machine they connect to. The main reason I used metal ducts is because I had a box of fittings left over from building my house.

Now if I’d had some 6” pvc laying around I would have probably used that. It’s definitely easier to work with. I’d use the dwv sewer drain pipe for most of it, but they do make 5” Sch40 pvc, if you can find it. The fittings for 5” are few and far between, but some can be found.

I’m going to finish the blog on my new system soon. So far it works great.

I’ve also found this link which helped a bunch. This guy really has a bunch of info and has done some considerable research. Good Luck!

-- Carl Rast, Pelion, SC

I’m not sure if this is the article I first saw but it says basically the same.

http://www.waterfront-woods.com/Articles/Electricity/static.htm

It is not done by any manufacturer or distributor of DC systems

-- No piece is cut too short. It was meant for a smaller project.

Thanks for all the replies. I am going to use thin wall PVC pipe for the long runs. Will get pictures as I move along with this project.

-- Genius is immediate, but talent takes time.

I read an article where it suggested using metal tape on the inside of the plastic pipe. the trick was smoothing it to the inside of the long runs of pipe. the connect the tape ends with a hole to the outside and seal the holes. This is a way to get the benefit of groundable metal on a pvc system

-- making sawdust....