Long Sweep 90 Elbows for 2729 Pipe

[Rushton]

I've long thought I could not find long sweep 90-degree elbows in SRD-35 fittings to use with 6" thin wall D2729 pipe. Well, now I've figured out a solution.

Long sweep 90-degree elbows are available in Schedule 40, but the diameter of the hubs is larger than SRD35/D2729 dimensions. However, you can retrofit to make them work.

The bell end of a straight section of D2729 6" pipe will almost exactly fit into the 6" Schedule 40 hub. So, cut the bell ends and make bushings with them as shown in the photos below. The fit will be loose, but when all is connected, a bit of silicone caulk will seal it all. To deal with the slop to the fit, I used screws through the 90-degree elbow's hub wall and into the "bushings" using 1/2" sheet metal screws. And then ground off the protruding end of the screw.

 

[Curly1]

Have you considered turning a mandrel of wood that you could expand heated pipe over? Then the pipe would fit directly into the elbow without having the "bushing".
Can't try it myself as 6" and larger PVC pipe is scarce and expensive here.

Pete

 

[Rushton]

6" pipe has been very hard to find here, also. I recently needed another stick of D2729 and no one had any. Ended up with a stick of D35 instead.

Forming bell ends for a direct fit is certainly an option, but I haven't tried it. I am working on turning a form to create bell hood ends per BobL's recommendations. Once I can form the BHEs, I'll retrofit some of my machine cabinet connections and add some over-the-table suction.

 

[Curly1]

You understand the principles then. A few years ago I was quoted $16.00 to $24.00 per foot for 8" PVC, 6" lower but not a lot and the fittings were equally obscene.

There are speaker ports sold by some of the online stores catering to audiophiles that build their own speakers that are the right shape for bell mouths, 4" being relatively easy to find and the 6" a little harder. I'll try and dig up a link I bookmarked. They were pretty inexpensive.

https://www.parts-express.com/Precision-Port-PSP-6OFN-Flare-for-6-Port-Tube-268-384

Pete

 

[Rushton]

Thanks for the link, Pete. It would be interesting to compare these to those that have been formed using BobL's recommended 1.5R curvature. I suspect that any performance difference might not be noticeable. Good to have a ready-made alternative!

 

[Curly1]

Looking further into the info on that link including Questions it says the inside diameter is 6", with wall thickness of 1/8", and an outside diameter of 9 1/4" and that it doesn't fit in/over PVC pipe (no specifics on which one). I take from that the radius will be 1 1/2" (1.5R) but one might be back to the age old problem of fitting the different types of parts (pipe and hoses) together like your solution of fitting to the elbow, the subject of the thread I derailed.

Pete

 

[Fingerpicker]

Finding the fittings for 6" S&D pipe is indeed a challenge. When I put my system together in 2013, I found the pipe at Tractor Supply and was able to order the fittings, including 90 degree sweep ells from McMaster Carr. Your bell end bushing does look like a pretty good work around though.

 

[Rushton]

Finding the fittings for 6" S&D pipe is indeed a challenge. When I put my system together in 2013, I found the pipe at Tractor Supply and was able to order the fittings, including 90 degree sweep ells from McMaster Carr. Your bell end bushing does look like a pretty good work around though.

Good for noting two good sources for 6" fittings. As others have noted, landscape supply retailers are often the best local sources since plumbing supply stores often don't carry sewer & drain pipe. The following post contains a list of additional sources that I found during my most recent installation of a Clear Vue CVMX system:

https://www.clearvuecyclones.com/for...4495#post14495

Unfortunately, none of these sources provide a true long sweep 90 SDR 35 fitting. Thus the Schedule 40 fitting shown being adapted here.