6" flex pipe to PVC?

[Mike Cruz]

Ohhhh, I was hoping that I wouldn't run into this problem, but I did...:(

I'm running 6" schedule 40 PVC (S&D fittings are not readily available around here...even at Lowes... Let's not get into the discussion, please). I have just made a fitting for my jointer and now need to connect the 6" PVC to the 6" flex pipe.

How have ya'll done it? I know I could cut a slit in the flex pipe, and have it go outside the PVC, then tape it up... but I don't wanna. Is there some sort of fitting/adapter for this?

Heeeeeellllllllppppppppp!!!!!!!!!!!!:eek: :eek:

[Steve Bigelow]

My quick and dirty method I put in place 8 years ago is still holding. Just butt the flex up to the PVC and use several wraps of a good duct tape to the connect them. Doesn't look too professional, but it is quick, easy, cheap, and it works.

[Matt Meiser]

For S&D I've used a short length of 6" snaplock pipe. It slips into the S&D, hose slips over the snaplock after crimping it. Not sure if the ID's are the same though.

[Steve Peterson]

Put a couple of clamps around the pipe and tighten them down. Heat the end with a heat gun and keep tightening the clamps as the pipe gets soft. Once the PVC gets soft, it becomes really easy to tighten the clamps. You can easily reduce the diameter by 1/4" or maybe 1/2".

A few hints:

Use plenty of ventilation. Burning PVC is supposedly very dangerous.

Wrapping a band of sheet metal under the clamps will give you a smoother looking result. Otherwise the PVC will squeeze around the lines in the clamps.

It may help to stuff a wooden circle inside the PVC pipe to keep everything round. This would prevent the pipe from buckling.

Steve

[Jim O'Dell]

It fits tightly over the 2729. What is the OD of the sch 40? The metal wye I used on my exhaust was way too small for the flex. But it fit inside the 2729 tightly. I cut a 1" wide piece of the 2729 and put on the metal part to put the flex on. You can heat the flex hose up to the point that it will stretch easier. Maybe that would get it on the pipe. Also, file the outside edge of the pipe to make a gradual slope so the hose goes on easier. Jim.

[Mike Cruz]

Matt, is snap pipe duct pipe that I can get from the Borg?

Jim, what is 2729? And yeah, duh, I never thought about sanding down the end. I may actually be able to take enough off, evenly, to get it small enough for the flex pipe to slip on. I'll have to measure the flex pipe.

Oh, and I think the OD of schedule 40 is about 6 5/8".

[David Hostetler]

Mike,

Yeah, Snap Lock pipe is the duct pipe you get at the BORG. The heavier galvanized stuff... (not the ultra thin aluminum stuff).

What I typically see, and not everyone does it this way is...

#1. Blast gate slips into PVC duct and is fastened with some clear silicone.
#2. Flex hose is slipped over other end of blast gate, and then clamped down.

YMMV depending on your particular hose and blast gate. Some Blast Gates are made for metal pipe and smaller in diameter...

[Matt Meiser]

Jim, your flex must be bigger than my flex. I can barely get it over the snap lock without some crimping--no way I could get it over the 2729.

I think the gist is that you have to do some experimentation.

[Alan Schaffter]

Like Matt, no way could I slip my wire reinforced flex over ASTM 2729 S&D so I slip it inside the bell end, but my technique might work with Sched 40.

I slip the pipe inside the bell end of a short piece of pipe or you can slip it inside a coupling- they act as my quick disconnects.

Have you tried putting the flex inside a Sched 40 fitting or coupling? It will likely be looser than inside S&D, but you can always coat the inside of the coupling and outside of the flex with polyurethane glue and spritz them with water to activate the glue before slipping them together. The Poly should expand to fill the gap.

Each end of the flex has a piece of pipe with bell end. My blast gates are made with 1/2 a coupling on the flex side and a piece of pipe on the machine side. My ports are made with 1/2 of a coupling (machine) or a full coupling (in wall and floor). Everything slides together and comes apart easily.

As I said this is S&D, but it may work with Sched 40 just be looser.

http://www.ncwoodworker.net/pp/data/1329/medium/P3070161.JPG

http://www.ncwoodworker.net/pp/data/1329/medium/P3030143.JPG

p.s. I am working on a shop tip on how to make bell ends with a lathe and heat gun or propane torch- easy to do once you make a "plug."

[Mike Cruz]

I'm making my owm blast gates similar to Alan's. I just thought that I'm not the first to do this, so someone must have found something or manufactured something that really fit the bill. The ideas I've gotten so far have sparked a lot of creativity for me. I think I have some possible solutions. But I'm always open to more...;)

[Mike Cruz]

Thanks, Alan. Schedule 40 fitting are WAY big for flex pipe. And the pipes don't come with bells. You have to use couplers. The glue thing might do the trick.

I was thinking of the heating and plug idea, but couldn't really figure out how to do it...not easily at least. I'll take some flex with me to the Borg and see what I can come up with.

Oh, and with the OD of schedule 40 being about 6.5", I'm not so sure that taking material off the outside of the pipe to get the flex to slip over it will work...BUT I might be able to remove some from the INSIDE so I can get a tight fit with the flex pipe go in.

Now, how to remove stock from the inside of the pipe...without melting the PVC with high speed grinding...and no, my lathe isn't set up yet (one of 10 projects "in the works").

[Alan Schaffter]

Thanks, Alan. Schedule 40 fittings are WAY big for flex pipe. And the pipes don't come with bells. You have to use couplers. The glue thing might do the trick. See, you should'a searched harder for S&D fittings! Sched 40 is EXPENSIVE and HEAVY!!!!!


I was thinking of the heating and plug idea, but couldn't really figure out how to do it...not easily at least.

Here is the "plug method"- You need a lathe. Turn a wooden plug that is about 6" long. Make the diameter of the first 2" slightly smaller than the ID of your (Sched 40) pipe. Size it so it slips inside but is not sloppy. Make the diameter other 4" the same as the OD of your flex. Taper the transition between the two sections.

This next part can be done on a bench with clamps, it is just easier to heat the pipe uniformly using a lathe.

Mount an 8" - 10" long piece of PVC pipe on your lathe. Use a large 4 jaw chuck, Cole chuck, or your can easily make your own mount with a face plate and some ply. Insert the small end of the plug into the pipe and slide the tailstock up to and recenter it on the exposed end of the plug. Feed the tailstock center and lock it so there is axial pressure on the plug and pipe.

Clamp or use duct table to mount a heat gun or propane torch so they point at the last 3" - 4" of the tail stock end of the pipe.

Turn on the heat gun and the lathe (at the lowest speed.) As the pipe softens feed the tailstock center and force the plug into the soft pipe. Keep doing this until about 3" - 4" of pipe has been englarged. Let the pipe cool, remove the plug, and start on the next one.

Once you have made a plug, it only takes a few minutes to enlarge a piece of pipe.

A similar procedure that doesn't use a plug can be used to "draw" a pipe to make it smaller.

[Matt Meiser]

so I slip it inside the bell end

Just tried this--perfect! Its a little tough to get in there but once its in, its not coming out easy.

[Mike Cruz]

Alan, I will start by saying thank you for the explanation. IF I had my lathe going, it sounds like that would probably be my first choice because it makes everything fit like it should. Also, thank you everyone else for all the great ideas. Your creativity spawned mine, and I came up with a solution…ah, a perfect one…for me at least.

Success! Not only success, but pride in my success. Not only that, but it looks good! So, as I sit here at roughly 9:30, celebrating with a Crown Royal, I’ll splain…

I was just getting done turning the horses out and cleaning their stalls, when I came downstairs to my computer to check to see if anyone had a “eureka” moment for me. And I realized that we just had a thunderstorm and that my wife had put some of my stuff that was to go to my shop outside the back door. Shucks! A drop cloth…oh well, it’s soaked. Oh, and the…the…6” metal duct coupling (crimped on both ends…about 10” long) was out there! Hey, I need to go see how that fits! So, I took it out to the shop and one of the crimped ends fit inside the flex tube perfectly. The other end went in too easily, but the OD of the coupling itself fit the ID of the PVC perfectly. I thought I had it, but then I looked inside the coupling to see that the sharp edges of the crimped end were sure to trap shavings coming down the pipe. So, I had to start over. How do I get the flex pipe over the PVC? Then the ideas that were given to stretch and heat, etc, got me thinking.

Why won’t the flex go inside or outside the PVC? The stupid metal reinforcing wire, that’s why. Well, what if the wire weren’t there? (Excuse me a second, I need to sip my Crown Royal at this point, because I’m having a tap myself on the back moment.……………………………….ahh, smooth.) Now, where was I? Oh, yes, the wire. What if the wire weren’t there? Hmmmm. What if I removed the last 3” of the flex pipe’s wire? So, I cut the wire about 3” from the end of the flex pipe (without disturbing the integrity of the plastic underneath it) and tried pulling it out. No luck. So I carefully cut a slit on top of the wire, patiently taking my time, not cutting myself, then I pulled the wire out. Now to test my theory… (sip) ((now, not at the time…that would be irresponsible))…

Well, it took some muscle (and squished fingers and sweat and frustration and some choice words), but I got it ON!!!!!! The second one went even smoother! (Knowing that I just had to “do it” and not try to finesse it.) So, to make a long story short (too late), just remove the wire, and you can stretch the flex over schedule 40 PVC, thus not reducing the air flow even more (considering that flex pipe reduces flow with the friction of its walls) by using a blast gate that goes inside the flex pipe. And also, not putting the flex pipe inside the PVC, creating a sharp “hang up” rim for shavings to get lodged in. Of course, Alan, with the way you do it with S&D, that is minimized because you use the bell.

Well, finished that Crown, I think I’ll have another…. Of course this lofty, fantastic, successful feeling will only last as long as it will take for someone to respond with a reason why my idea will fail…poo on you…

Oh yeah, I forgot to say that my 6” flex pipe clamps that I purchased from Grizzly don’t fit around schedule 40 PVC, so I’ll have to get some from the Borg. Not Grizzly’s fault. It’s not like they say “Use this for schedule 40 PVC” or anything… Why am I still typing…my glass is empty.

EDIT/ADDITION: While I know/realize I was just tooting my own horn there, I also KNOW I couldn't have done it without all of your help. Thank you, thank you, thank you....really.

[Jim O'Dell]

Yes, the S&D 2729 is 6.2" OD. I think they brand of flex hose makes a big difference too. My cyclone came with a short piece from Wynn Environmental at the bottom of the cyclone. I fought for an hour trying to get it over the stub pipe going to my collection barrel. NO WAY was it going to fit, even with the heat on it. But the hose I got from Woodworker's Supply works much easier. It isn't as heavy duty as the Wynn hose, and I guess it could be slightly larger diameter. You still have to work it on, but a little heat and beveling the ends slightly makes for pretty quick work.
Sorry I didn't answer last night...lost a 40' limb off the Bradford Pear in the back yard the night before, and it took out the cable line. Not sure how it missed the electrical line 2' above it!!!:eek: Jim.

[Rob Wright]

sizes of PVC - both SDR and SCHD sizing:

http://www.sawmillcreek.org/showpost.php?p=597206&postcount=14



http://www.sawmillcreek.org/attachment.php?attachmentid=65855&d=1181052320

[Alan Schaffter]

sizes of PVC - both SDR and SCHD sizing:

http://www.sawmillcreek.org/showpost.php?p=597206&postcount=14



http://www.sawmillcreek.org/attachment.php?attachmentid=65855&d=1181052320

Thanks Bob, I couldn't find my chart.

This chart illustrates, directly and indirectly, a number of significant points.
The ODs of S&D and SDR35 are the same but are different from Sched 40. The ID's of all are different, but the ID of 6" S&D and 6" Sched 40 are close (6.075 and 6.065)
And not to be overlooked, S&D is the lightest and Sched 40 is by far the heaviest!!!