What can I use as a big metal crimp tube for binding hair?

I'm trying to find something much like the metal crimp tubes used to bind the plastic hair for My Little Pony tails. I have many who are missing theirs because they pop out easily when pulled on, revealing that all they did to apply them was

1. cut a piece of hair twice the length of the intended tail piece

2. bind it tightly in the very center with a piece of bendable (and rust-able) metal

3. push the metal tube lengthwise into the hole for the tail and

4. pull the shorter side of the tail even so that the side of the crimp exposed to the hole is too big to fit back through the hole,

like one of those plastic T-shaped tag strings found in most department store clothes as well as stuffed animals and other fabric products. Does anyone know what else I can use to make new tails without damaging the ponies at all?

What can I use as a big metal crimp tube for binding hair?

1) measure the size of one of the holes--use whatever system is dominant in your region (i.e. English system in the US, metric anywhere else).

2) go to the hardware store. Find a piece of tubing that is the same size. It may be marked, it may not, so bring something to measure with you. If they don't have it, ask them to recommend someplace else.

3) Cut the tubing up, after making sure it fits in the hole. Attach the hair inside the tubes--glue would probably work best.

4) insert the hair/tube assembly into the hole. The tube should fit tight enough that the pressure should hold it in.