PVC Elbow effect - Page 2

Twins Guy · 08-14-2003, 12:43 PM

dang graham you beat me...not trying to instigate with that last post

Crevalle · 08-14-2003, 12:45 PM

Interesting.

uryy4me · 08-14-2003, 01:12 PM

FYI - folks at HD call flex PVC "spa tubing"....I don't recall seeing this in 1.25", but I know they have it in 1" and 1.5"

I just completed a project where I went through quite a bit of this stuff and I glued it to fittings just as if it were normal PVC.

In my novice opinion it is harder to join than normal PVC but that was because I often had angles near a join. I found it much easier to work with if it was glued w/o any bends near by and then once it was dried it could be put in place and bent (otherwise it wants to pull out of joints).

BTW - HD does not crary the cement made specifically for flex PVC but they do have a heavy duty (green label container) that worked for me (it is thicker and has a bit more "work time")...don't forget to prime!

Oh, one more thing, as already stated in this post Aquatic Eco also carries this and I found their product to be less ridig and easier to work with than the stuff HD has (where bends were concerned).

Stoney Reef · 08-14-2003, 01:14 PM

Twins guy is correct that is "true flex pvc" It is made to be solvent cemented to normal PVC fittings. Just think of a pvc pipe that is somewhat flexible. I said somewhat because it is not too darn flexible unless you get it a bit warm or use a lot of muscle. Crevalle, what I believe your talking about is the flex pipe that come with the overflow boxes, and that is made so the end has a rubber coupler that fits over a pipe and is clamped in place. Two different animals for Two differrent jobs. I like the really flexible stuff going to the sump. and flex PVC for connections otherwise. I hope that clears it up.

Crevalle · 08-14-2003, 01:16 PM

I was at HD about a week ago, and they had every size you can imagine (up to 2"). Yes, it is referred to as "spa tubing," but they also have clear vinyl tubing in assorted sizes--some quite large. I wasn't as big of a fan of the spa tubing because the inside of the tubing is not smooth like the vinyl tubing, and it is thicker. It probably wouldn't make much of a difference in flow, but every little bit counts.

Stoneyreef--thanks for getting us on the same wavelength! You are correct--I have been referring to the tubing that is quite flexible (same tubing that comes out of my overflow). Good call!

Graham · 08-14-2003, 02:01 PM

Twins Guy,

Good point.
As far as I know, this is "true" flex PVC that I am using. It is fairly sturdy (thick, very dense) and when you bend it, it does not compress at all. This limits the degree to which any given length can be bent (you would need a longer length for a tighter bend). However, it is definitely flexible. No tools were required to insert or bend it. I used an electric miter saw to cut it.

dirk griffin · 08-14-2003, 02:11 PM

I did not read all of the replies, but I recall every 90 degree turn with PVC.. approximately.....slows/affects the water flow by 2 1/2 percent.

Dad · 08-14-2003, 11:26 PM

I have heard that each elbow is roughly equivilant to adding 1 ft of head to the return....I have seen that here a couple of times in the past....

I believe 2 45's would be better that 1 90 because of the angle of the turn is less with the 45's creating less resistance, but take up more room to complete the turn....
I think that would be about my $.02 worth of knowledge on the subject.....

bob

marm64 · 08-14-2003, 11:55 PM

Quote:

Originally posted by Dad
I believe 2 45's would be better that 1 90 because of the angle of the turn is less with the 45's creating less resistance, but take up more room to complete the turn....
bob

This all depends on the pipe. On some PVC fittings they do sell slow sweep elbows so as to try and reduce the head loss as much as possible.

latazyo · 08-15-2003, 02:37 PM

flex PVC connects like regular PVC pipe, flexible tubing as you say, is vinyl

the problem with vinyl is that it will kink, if you are afraid of kinking, then you will want to go with the flex PVC

I use sump pump hose on my drain because 25' of it and hose clamps AND the thing that connects to your bulkhead and then to the pump hose is all included in a nifty little kit for FOUR DOLLARS....so that's what I use for my drain....good luck with teh project jake

FastFish720 · 08-20-2003, 12:52 PM

Actually I just found one of those and bought it. I tried this other stuff and it didn't work so hot.

Dad · 08-20-2003, 01:38 PM

I found some information on the subject of resistance calculations
using PVC...It is in the AquaticEco Catalog...maybe on their webpage also...give lots of information about using pipe, fittings etc...

www.aquaticeco.com

HTH
bob

latazyo · 08-20-2003, 11:04 PM

what cement is used to join spa flex to PVC (I realise you said green label, but what are you talking about)

so regular PVC cement won't work?

Asbjorn · 08-21-2003, 01:01 AM

The flexible white PVC commonly referred to as "Spa Flex" is usually solvent welded using rigid PVC elbows etc. Take a look at a hot tub. Another option, the clear nylon reinforced vinyl tubing sold at Home Depot is also PVC (read the print on the tubing), and can also be solvent welded to standard PVC fittings. I have used this option, with no leaks, however it is probably not as sturdy as Spa Flex since it is not reinforced.

civil · 08-21-2003, 12:59 PM

I had to go look this up and it is for large pipe, mostly watermain and the sort but anyway. The loss coefficient of an elbow is considered to be 1.5 and a 45 is around 0.4. This is for a fitting that would be similar to what you are talking about. I use 2 90 elbows on my overflow return with no problems. The line is not under pressure, there is some air sucked through so the loss is even less due to open channel flow, or something close. The only time you need to worry about loss is in higher flow situations. It is likely that none of us have true high flow with our little pumps.

ELBOW CHANGES