Brass barb fittings for poly pipe

[Bob S.]

I plan to connect a new run of 3/4" ID poly water pipe from the well in my summer camp this year. I bought 3/4" brass barb fittings to join sections but they seem very loose fitting inside the poly. Do you need to heat the poly to compress with clamps or use some kind of compound for a tight seal? The plastic barb fittings are VERY tight inside, but I'd prefer to use brass for strength and longevity. Anyone have guidance to offer? Thanks! Bob

 

[Valveman]

The barbs on plastic or brass should be the same size. They have to be pretty tight to start with, but even then heating a little is recommended.

 

[Sponsor]

 

[Reach4]

I presume you have the wrong barbs. If you got a pex fitting, that would be very loose.

https://www.homedepot.com/p/Water-Source-3-4-in-Brass-Male-Insert-Adapter-MA75NL/203449562

 

[GORP]

I plan to connect a new run of 3/4" ID poly water pipe from the well in my summer camp this year. I bought 3/4" brass barb fittings to join sections but they seem very loose fitting inside the poly. Do you need to heat the poly to compress with clamps or use some kind of compound for a tight seal? The plastic barb fittings are VERY tight inside, but I'd prefer to use brass for strength and longevity. Anyone have guidance to offer? Thanks! Bob

I am having this issue now. Can you provide an update on how you addressed it? I thought everyone measured 3/4" the same too, yet the brass is too small, like I need 13/16 or 7/8 to fit the 3/4 pipe.

 

[Bournefort]

I plan to connect a new run of 3/4" ID poly water pipe from the well in my summer camp this year. I bought 3/4" brass barb fittings to join sections but they seem very loose fitting inside the poly. Do you need to heat the poly to compress with clamps or use some kind of compound for a tight seal? The plastic barb fittings are VERY tight inside, but I'd prefer to use brass for strength and longevity. Anyone have guidance to offer? Thanks! Bob

Did you end up figuring this out? I have the exact same problem. I bought 400ft of 3/4" ID polyethylene tube from the hardware store to use on a sprinkler system in my yard. I went to insert my 3/4" brass barbs and they went into the tube with almost no resistance. Super loose. As a sanity check, I brought my 3/4" barbs to work and tested them on the 3/4" tubing we have there. Perfect fit. Super snug, just like it should be.

Brass Barb OD measures 0.810" and the polyethylene tube ID measures 0.824". I checked the manufacturer website for the tubing, and it says 0.824". Why the discrepancy? There is no standard barb OD size?

 

[Bannerman]

Brass Barb OD measures 0.810" and the polyethylene tube ID measures 0.824".

Many brass barb fittings, are sized for use with vinyl (PVC) or reinforced PVC tubing. Those fitting diameters are typically too small for use with the same nominal diameter of polypipe.

Some hardware stores only stock PVC barb fittings sized for polypipe, but some also stock a limited selection of galvanized steel barbs for poly.

The same nominal diameter of type 'B' PEX fitting barbs, are not usually compatible with vinyl tubing or polypipe as PEX 'B' ID is typically even smaller in diameter.