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Looked up making your own fittings and found the guy used ca glue.
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I think you might be referring to the generous fellow who offers a limited version of his excellent pipe fitting program on line. Don't have the link handy, but he uses CA glue for his wyes. To be honest I have not tried CA glue on PVC with or without the Activator. I really should give it a try and was thinking that it might be useful for tacking joints before welding. However, there is just about a quarter inch of surface on thin wall PVC and I guess I don't see how that would be enough contact area to be secure. But it is not like I would be using a glued up fitting to bear any weight. I just wondered about the inevitable kick or bump into stuff that happens pretty regularly. I did try the regular PVC cement but it makes the edges too soft and I did not find that a very clean or smooth joint, besides which it is not mechanically very sound. Works great with more surface area like when used as intended though. If there is experience with CA glue and PVC joints I would like to hear about it.
[OP]
Member
The Lowe's 90's arrived two days ago. They are probably 1.5D radius. However they are for schedule 40/80 not ASTM2729, so they are too big. Will return them and use two 45s. The M-C units are specified for ASTM2729 and are reported to be 2.5D Radius.
Contributor
One option I looked at was heavy equipment exhaust. I found steel sweeps for about $70. Pipe was too expensive.
I checked out aluminum irrigation pipe, but there is not much for fittings.
Not any help, but thought I would throw that in there....
Larry
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It may not be the prettiest thing, but could you wrap electrical tape or something around the S&D pipe to shim it to fit the 90s?Originally Posted by Todd Brewer
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I think many of us would love to hear about your experience with these McMaster-Carr fittings. I looked them up and the 6" S&D is part #9102K116 would be great if it was indeed 2.5x radius. I did not see them spec'd as 2.5x radius. But I just emailed them to ask. At $31 these would beat the labor and PITA of fabricating long radius 6" 90degree elbows. Amen.
Because I am a preternatural dumpster diver I have kept an eye on my local Craig's List and come up with all sorts of odds and ends. My remedy for the relatively svelte S&D pipe sized into the abundant Schedule 40 fittings is to use electrical tape at the very end of the S&D pipe and then to use silicone caulk to fill the void at the Schedule 40 fitting end. You have to shim the pipe on the bench to keep it centered in the fitting while the caulk dries. But then it is pretty solid. It is not meant to be permanent but it is very serviceable. At some point I could imagine using Liquid Nails or some more permanent epoxy when I am done with all the fiddling and ad hoc improvisation that is the current state of my shop.
Do please keep us informed. It takes only a day for me to get McMaster-Carr parts. They have a distribution center in Atlanta which is only 150 miles from me. I don't want to be a nay sayer but I have my doubts about what they are defining as long radius. It is why I have not ordered one yet to play with. But it would be great to be able to get 2.5x radius 6" pipe at that price point. Best of luck.
Last edited by Bruce Seidner; 03-31-2012 at 10:56 PM.
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This may help.....http://harderwoods.com/pipe.html
Chris
Everything I like is either illegal, immoral or fattening
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Another thing you can do, is avoid 90 bends if possible. I think my whole system has only one 90.
If you come off the main with a wye, you are already halfway there. Add a 45 and you have completed the 90.
One of the few 90's made with two 45's:
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90.jpg
In the words of Crocodile Dundee "That's not a 6" PVC 90...THAT'S A 6" PVC 90"
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Cool beans. I'd like to roll with that. How'd you do it? Step1....
[OP]
Member
I'm not going to order the McMaster-Carr 90s. I am using 2 45s or as Alan said a wye and a 45 (was already doing that at junctions). Maybe someone else will take the gamble.
The Lowe's 90's are going back.
[OP]
Member
Per Bill Pentz' calculator, SP loss for a 90 is: 1.5R .5 SP, 2R .33 SP and 2.5R .28 SP. He instructs to enter 45's as .5 90, but does not say which 90 value to use (1.5R, 2R or 2.5R). I guess if you found a 2R 90 you'd be in pretty good shape as the difference between 2R and 2.5R is only .07 SP.
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Wow, those loss numbers seem awful high. It does depend on the air velocity, though, so not sure what you are using for that. According to my reference text (ACGIH), a 2D 90, only looses .13" at 4000 FPM (smooth or stamped). You would need to be flowing about 6300 FPM, to loose .33"SP in a 2D 90, and I know the ACGIH numbers are considered conservative.
I'm not sure how your spread sheet works, but the usual convention is to add up the number of 90s of the same radius. If you have (2) 2D 45s, that is the same loss as (1) 2D 90, if you have (3) 30s, then that is also the same loss as one 90. You would need to determine the radius of your 45s to enter them in the sheet correctly.
The loss for the branch fitting, is typically charged to the branch duct. A 45 degree branch, has .28"wg loss at 4000 FPM. If you have a 45 degree EL (2D), and a 45 degree branch (a branch 90 degrees to the main run), the loss for these two fittings is .35"wg at 4000 FPM. I know you (and I) are limited on fittings for home use. But for example, in industrial systems, we use a 30 degree branch fitting, and a 60 degree (2D) elbow, these two fittings combined have losses of .25"wg at 4000 FPM. Its only .1"wg difference than two 45s, but makes for smoother branch transitions, reduces abrasion, and saves a little energy. Probably not an issue for home shop, if you get within .1"wg of what you calculate, you are better than most and well within margin of error. I just wanted to illustrate the difference between a branch loss and an elbow loss.
If you are a one-man shop, and you close or blank off the run side of the branch fitting and are pulling throuhg the branch only, I would still count the branch fitting losses instead of assuming they are an elbow. You really don't have any turning radius in a branch fitting, but the losses are probably less than a mitered elbow. Treating it like a branch loss may be a little concervative, but is a good middle ground.
All this being said, a 1.5D 90 looses .15"wg and a 2.0D 90 looses .13"wg at 4000 FPM. If you have gored or sectioned elbows, the losses are slightly different and favor the 2D more.
Mike
[OP]
Member
It's not my spread sheet, I'm not that smart.The numbers are from Bill Pentz' calculator which can be downloaded off his web site. Those numbers are based on 800 CFM and target air velocity of 4000 FPM.
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