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From: mmm@cup.portal.com (Mark Robert Thorson)
Newsgroups: sci.electronics
Subject: Re: heat shrink tubing
Message-ID: <35890@cup.portal.com>
Date: 13 Nov 90 03:07:14 GMT
References: <64.UUL1.3#1@vortex.COM>
Organization: The Portal System (TM)
Lines: 6

Correct, plastic tubing is irradiated to induce cross linking, then
stretched.  When heated, the crosslinks cause the material to pull back
to its original shape.

The radiation comes from electron beam tubes, essentially large X-ray
machines.