Re: ATM - The Right Stuff

["Frank Ward" <thewards@mindspring.com>]

Richard,
That last requirement eliminates the obvious cut up rubber condom which
somebody is sure to suggest.)

I wouldn't have even suggested it......unless you were making a secondary.
Size is critical you know.

However, I used heat shrink thermoplastic when constructing model aircraft.
It has all the qualities you desire.  If you can't get some locally
(cheaply....
it's sold in rolls) I'll be glad to mail you whatever you need.

Frank






----- Original Message -----
From: Richard
To: atm@shore.net
Sent: Wednesday, July 18, 2001 10:19 AM
Subject: ATM - The Right Stuff


When making tile tools and pitch lap foundations of dental stone, I have
been using saran wrap to cover the bottom of the mold and permit easy
separation.    This is OK for shallow curves like telescope mirrors, but
when the curve gets deep, the saran wrap wrinkles and those wrinkles get
molded into the surface of the casting.

Yesterday I tried a garbage bag, and it works MUCH better.  However, there
are still some wrinkles.

So, what I am looking for is the right stuff-- something that will stretch
under tension to conform to a convex mold surface, or stretch under the
weight of the dental stone or castable refractory to conform to a concave
surface.   Whatever it is will be cheap, commonly available, and come in
sheets big enough to cover a mirror surface.  (That last requirement
eliminates the obvious cut up rubber condom which somebody is sure to
suggest.)

Any good experience or ideas out there?

. . . Richard