On Sunday, May 21, 2017 at 7:32:33 AM UTC-7, Gary wrote:
http://s677.photobucket.com/user/gar...cock1.jpg.html

Petcock is probably zinc.

I was thinking, copper/brass tubing for reinforcement, with the
threaded piece slipped over it.

Probably not safe. The threaded part, that fractured, actually DOES
have to get tightened with a wrench at some point.
Get a good, natural-gas-type valve, like a lab would use on
Bunsen burners, if you want an upgrade.

That valve looks like a motorcycle fuel switch; search on Amazon for this part:
LUO101-MAP14-12-A099_01