I am just trying to connect an 1/2” vinyl tubing (this one) to a smaller 3/8” version.

I got this 1/2” to 3/8” barb reducer but it’s way too small and doesn’t fit.


Which part do I need instead?

2 Answers 2


The device you have linked to is for PEX pipe, which needs special crimpers. It is not deigned for vinyl tubing.

You need one of these: barb hose reducer barb hose reducer

(Admittedly, the link is for a set of 25, but a single wuold surely be obtainable.)

You will also need hose clamps.


In my experience (as a brewer), when mating a barb to tubing and everything is sized properly, it takes some significant effort to get the tubing on the barb. This is by design, so that you get a leak-free seal (usually in conjunction with a hose clamp).

Some strategies that might be helpful:

  • Soften the vinyl tubing by heating the end in boiling water before attempting to insert the barb.
  • Use a utility knife to cut a bevel around the inside of the end of the tubing (effectively increasing the inside diameter to make it a bit easier to get the barb started).
  • Pre-stretch the end of the tubing with something slightly smaller than the barb; perhaps something that has tapered thickness.

If I ever need to remove the tubing from a barb, I am almost never successful in pulling it off. I usually end up having to cut the tubing off of the barb, losing an inch of tubing in the process.

  • He said that the fitting is too small, not too large.
    – popham
    Commented Dec 19, 2023 at 20:46

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