RE: Vycor threads Almost everything you ever wanted to (or not) know about Pyrex, Vycor and quartz, glassblowing, torches, vacuum gauges, stopcocks, cryogenics, vacuum systems, etc... can be found in an excellent book by Gary Coyne entitled "The Laboratory Companion - A Practical Guide to Materials, Equipment and Technique". I highly recommend this book to anyone managing a stable isotope lab and it is a must read for all technicians and students that work in stable isotope labs. There is, for example, a great chapter entitled "How to destroy a vacuum system" where you can re-visit all the mistakes you have ever made and avoid some! The book is worth every cent. Details from the publisher are given below..... Len Wassenaar Environment Canada The Laboratory Companion: A Practical Guide to Materials, Equipment, and Technique Gary S. Coyne (California State Univ. at Los Angeles) ISBN: 0-471-18422-5 Hardcover: Price: US$59.95 Published: Sept 1997 Copyright: 1997 Imprint: Wiley-Interscience http://catalog.wiley.com/