Poly pipe to sprinkler heads - fittings not tight.

[Mandinca]

Good morning everyone.

I am trying to test a basic irrigation system above ground before trenching and burying the lines.
I bought the 3/4 and 1/2" poly pipe from Home Depot (the black stuff which is thin walled and kinks easily) as well as some rainbird heads, elbows, tees and reducing tees.
The plan is to run the 3/4" poly in a straight line for 50' with the reducing tees placed every few feet. The tees reduce the 3/4" to 1/2".
After that, the tees off to 1/2" will have poly pipe attached as branches off that 3/4" main line. The 1/2" poly attaches very snuggly to the reducing tee...won't leak with a pinch clamp. However, when I try to tie in the sprinkler head on the other end of that 1/2" branch line the elbow screws into the bottom of the head nicely but the 1/2" barb is loose in the poly. I tried wrappng it in PTFE tape but that hasn't helped. I have not actually tested it with pressure but, well, you just know don't you. I can actually probably pull it out if I try, I can certainly rotate the elbow in the poly.

So, is this a common problem ?
Am I using the wrong items ?
I bought a length of 1/2" swing pipe to see what happens and when I warm the swing pipe up the barb at the elbow for the sprinkler head will squeeze into it with some mild force. However, I then have no way to connect the swing pipe to the 1/2" poly.
Is my only option to juse the swing pipe for the whole branches ?
I read on rainbirds site that the swing pipe is usually only the lasrt couple of feet before the sprinkler head to allow for flex to bury the pipe.

Do I have to use rigid PVC for the main line and branches then a PVC connector to the swing line to then attach to the elbow for the sprinler head ?
I know I have seen videos of others using this kind of poly pipe and they don't seem to have the experience I'm having.

Thanks, some photos in the link here. https://photos.app.goo.gl/ASXP1EqBqK8MDkmaA

You can see what I am attempting to do and when I used a pinch clamp and tape I can rotate the barb in the pipe...so it's going to leak right at the sprinkler connection.
The T is the reducing tee where the main line will run but that main line pipe isn't connected in the photo.

Lastly, assuming there is a solution to this issue connecting the poly to the elbow, will the poly stand up to New England winter with the pipe only buried 4 or 5 inches under the surface but with the lines blown out each fall.
Has anyone else in NE done this ? Pros, cons ?

Thanks everyone, appreciate your input.

 

[WorthFlorida]

Exactly what poly pipe do you have? On the home depot site, poly pipe 3/4 in. x 100 ft. IPS 100 PSI UTY Poly Pipe has a larger inside diameter than the 3/4" NSF approved pipe. Look under the specifications. 0.824" vs 0.778". The barbs you have is for "Funny Pipe". You may have to find a supplier for poly pipe to get th correct size fittings. The only time I had to use clamps was when with too much pressure, it would blow off the funny pipe off the barbs.

In Florida poly pipe is not used for irrigation, it's mostly PVC pipe. On the low end of PVC pipe is labeled 3/4" x 10 PR 200 PIPE (200 Psi)). You can use Schedule 40. CT stores may not carry it the 200 PSI. If you go with PVC as the feeder pipe, every thing will be so much easier.

You need to bury the pipe about 12" because when you tee off for a sprinkler head, the bottom of the sprinkler is either 4" or 6" add an elbow and you need it to be flexible to get the top of the sprinkler head at ground level. From the feeder pipe to the sprinkler, tee off with a barb fitting (a straight one), a length of funny pipe about 18"-24" a 90º barb, then the sprinkler. It's a home made swing pipe.

 

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[John Gayewski]

Agree it sounds like your pipe and fittings are for a different sized pipe than your heads. You'll need an adapter.