DC Ducting Questions

[Rick Huse]

Hi, I just purchased a Grizzly 1029Z DC. It should do what I want it to do but I do plan to convert it with the Wynn cartridge filter modification, 35A kit at some point.

My shop is 28 x 35 and I plan on 25' of 6" main with three 4" branches totaling 60'. All are machines are generally close to one wall. I have been researching the different ducting. Spiral ducting over a $$$ grand. Found all the snap-lock in the right gauges and fittings and with best prices from three different vendors it came up to 505 dollars before shipping. So those being a real stretch to an already stretched budget I am looking into PVC for ducting.

There are three 6" tees but looking at the fitting they are virtually 90 degree tees. Will regular plastic fittings from Grizzly or other places meant for dust ducting fit the PVC? What other problems lay ahead for this type of ducting? I plan on the Lee Valley self cleaning blast gates. I have been looking online at PVC sellers, I maybe not understanding their pricing, but 6" fitting seem to be VERY high priced when compared to the 4". Any comments or pointing in the right direction would be helpful. I am running the main ducting mainly along a wall under a 22' yet to be built bench for my mitre saw and mortiser. The DC will be enclosed in a small room built for it and the separator.

Thanks, and Merry Christmas
Rick

[Chris Padilla]

http://www.mcmaster.com/ Search on "Drain, Waste, and Vent PVC Pipe"

You do NOT want schedule 40 fittings: very pricey and not at all necessary.

The pipe you want is either SDR35 or ASTM D2729. Expect to pay $17-25 per 10' length of 2729.

I also used 2 45s to make up a 90 as it is cheaper than a long-radius 90...and probably long-radius enough.

[glenn bradley]

In SoCal 6" ASTM2729 is about $13.50 a 10' stick, 45* elbows (I'm with Chris on the daul 45* vs. 90* idea) and wyes are about $14. I just picked some up after what I thought was a dead end search. A forum member who lives a long way from California put me onto Horizon (http://www.horizononline.com/) who had a warehouse/store 10 miles from work as well as across the country. . . sweet.

Got everything I need for a fraction of other materials. Obviously PVC is not rolled steel but, I'm just Glenn, not Glenn's Wooden Widgit Co.

P.s. 6x6x4 wyes here (http://www.acehardwareoutlet.com/(b2s5ncqevwh20545cn4qrizd)/productdetails.aspx?sku=4037958&source=GoogleBase) if that helps.

P.p.s Avoid tees and sharp 90's whenever you can ;-)

[Jim O'Dell]

For PVC, Glenn has the right formula. Use 2 45's to make a 90 with a short piece of straight between them. Don't forget some flex hose. Lots of people like the stuff from Wynn Environmental. I got mine from Woodworkers Supply. It's not as thick, but it works fine. I got most of my fittings from McMaster-Carr that Chris linked to. Fast and reasonable shipping costs. The 6/6/4 wyes came from Lowe's. About 20.00 each, and not all Lowe's have them. Only place I could find them locally, because I hadn't found Horizon yet. The place I got my pipe from say they have NO fittings for the 2729 pipe. :confused: Makes no sense. Yes, 6" fittings are a bunch more than 4". But if you think about it, the volume area of the pipe is over double the 4", so there is a lot more plastic there, and I bet 6" isn't used as much as 4", so recouping tooling costs takes a long time, or they need more money on each to make it feasible to produce.
Many have said that they can buy spiral pipe from their local small business fabricators. They are almost as hard to find as 2729 pipe, but those that found them say the price was about the same as PVC. You might ask a few HVAC people where they would go locally to get it. Hope this helps. Jim.

[chet jamio]

What is a good way to connect a blast gate or flex hose to 6" PVC? I'm trying to figure this out and here are the dimensions I have:

PVC OD 6.275
PVC ID 6.075
blast gate OD 5.900
flex hose ID 6.000

[Jim Becker]

Chet, the best way is to make your own blast gates. The are more efficient and will mate with your duct "exactly", rather than having to deal with the pain of making commercial gates adapt to duct made from irrigation/plumbing pipe.

[chet jamio]

I've read that making them is better, but blastgateco has 6" gates for $8.17. It would be much easier to bolt them on. All that is needed is pipe with approximately 6" OD and 5.9" ID. I could buy some .050 steel and make my own.

The blast gate ID is 5.58". The flow area is 84% of the PVC pipe. Add to that the disruptions caused by the diameter changes and it's probably worth avoiding. Building some may not be much harder than adapting off-the-shelf versions anyway. Thanks for the motivation.

For others interested, I did a search and found the following links:
http://web.ripnet.com/~scater/Blast_gates.htm
http://www.sawmillcreek.org/showthread.php?t=42643&highlight=BUILDING+BLAST+GATES

[chet jamio]

I still need a way to attach flex to the PVC. Any help? The two methods I've read on the forums are 1) make a sheet metal tube to fit inside the PVD and inside the flex 2) shrink the PVC using heat and a clamp until the flex slides over. Are there any other ideas?

[Ray Schafer]

I don't know what it is called, but in the plumbing section, you can get a rubber tube with clamps on each end. They come in a variety of sizes and come in step up sizes -- like 5" to 6" for example.

[Sonny Edmonds]

4" blast gates will fit right into the I.D. of 4" S&D pipe, snug and secure.
I've used them all over the place in my shops now.
And a manual choke cable from the auto parts store, with a lever to multiply its travel, makes for a remote operator for the gates. (http://home.earthlink.net/~pie/images/shop_shots/remote_gate.jpg)
Make your home runs 6", and lateral inputs (http://home.earthlink.net/~pie/images/shop_shots/manifold_1.jpg).
Where you make verticals use long sweep ell's like this one (http://home.earthlink.net/~pie/images/shop_shots/manifold_2.jpg)from my booster blower. With these lateral inductions everything keeps heading to the collection point at all times.
And lastly, at the end of the run from the collector is a 6" sweep 90, reduced to 4" with a blast gate for machine connection and a 4"X2.5" reducer that connects to my SCMS. (http://home.earthlink.net/~pie/images/shop_shots/manifold_3.jpg)
The 2.5" is always open to the SCMS, so it allows a small amount of free air to sweep the main run toward the collector (cyclone, in my case).
This is the end result of years of development of shop made collection and it really works well. I no longer dock my roll around tools here, rather I dock them to a port at the front of my TS that is drawn on by the booster blower. 2-3 times the suction power of single stage system there. So it really sucks the Band Saw, Planer, or Jointer clean in use.
Hope some of this can help you with your set-up. :)

[chet jamio]

I picked up my 6" S&D yesterday and started my install. It's a tight fit, but the 6" flex I bought from Wynn can slide over the the PVC pipe. I had to put a 45 degree chamfer on the PVC to get it started. I'll be making blast gates today.

On a side note, I thought S&D and 3034 meant the same thing. When I was at the irrigation supply house, I found that S&D is white with .100" walls and 3034 is green with .180" walls. Consequently, the S&D is cheaper, looks better, is about half the weight, and cuts easier. They both use the same fittings.

It was very easy to find the pipe and fittings. I googled "irrigation supply" and started calling. All of the businesses under the "wholesale" category were willing to sell to me. Most had everything in stock. Not nearly as difficult as most posts have made it seem.

[Burt Alcantara]

I use the gates from Blast Gate Co. on ASTM 2729. My first attempt at connecting them was to use duct tape around the gates and a number 7 metal screw. Worked OK but was messy.

This time around a 6" length of 6" PVC onto the gate then filled the gap with latex caulk. Let it dry for a few days. The seal is air tight and strong. For 4" gates, cut a piece of PVC 4" long and do the same.

The reason for these lengths is to get an even seal between the joins.

I use couplers to connect hose to pvc. It's a bit more expensive but I've not been able to find a better method yet. Tried heat guns, slashing, hot water, etc. The hose will fit snuggly in the coupler and just stick the pvc into the other end. If you need to readjust it's easy to pull out the coupler and reuse it later.

I cut 4" ducting on my 10" miter saw.

The 6" goes on the table saw. I raise the blade about a generous 1" and measure the piece up to the rip fence. Using my miter gauge held in place with a clamp, I lay the pipe down on the running blade so the far end of the diameter is engaging the blade and just turn it on the rip fence side while maintaining pressure on the opposite end. Works great.

To cut large lengths to size I use a recip saw. Bungie the stick to a small table. I use a large blade marked for PVC available from the box stores. Make sure the stick is firmly bound then just do a straight down cut. If it comes out a little (or a lot) ragged you can clean it up on the table saw as mentioned above.

Burt

[Sonny Edmonds]

All depends on where you are.
It's a damn site harder to find 6" S&D here in Northern LA county than you could imagine.
I scraped together 30' of 6" S&D, then ordered my fittings through McMaster-Carr.
My order arrived the very next morning from them and I was hanging pipe! :)
I like S&D for my systems. It has proven to be much quieter in operation, and miles easier to work than metal was.
Have fun! ;)

[Rich Boehlke]

Attaching flex duct to PVC can be done by cutting several slots about 1 to 2 inches long in the end of the PVC. I used a bandsaw. It makes the end of the pipe compressible enough to get the flex started over it. Work the end of the flex on far enough to cover the slots. It takes a bit of grunting but results in a good tight fit. Add a hose clamp for extra security.

Rich