Re: ATM pitch to soft

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

Larry,
> Hoping to avoid dumb mistakes, thanks.   LFD

The dumbest mistake I made was trying to follow
book instructions too closely without experimenting
for myself. Your test turned out differently than the
one proposed by a Frenchman in the 1960's (That
he probably had been using since the 1930's) Was
the temp in the room the same as his, the humidity,
the pressure behind the fingernail? Was his pitch
the same formula as yours? How about his mental
condition? Were you or he in a hurry?

May I respectfully suggest that you start polishing with
the lap you have and take notes for yourself on the
results? In an hour or two you will be able to say,
Ahhhhh so >that's< what 3 second pitch does. Then
you can either keep using it or remove it and boil it
a little. Then use it again and you'll be able to say,
Ahhhhhh so >that's< what 10 second pitch does
differently.

That's what ATM's do. If you just want a mirror and
save a few dollars over the price of one made for you
then ignore my advice. But, on this List most of us are at
least as interested in improving our knowledge base
and experience as we are in making mirrors and scopes.

Your call.

Frank Ward
Atlanta, GA


----- Original Message -----
From: "Larry Davis" <Davis@digdat.com>
To: <atm@shore.net>
Sent: Thursday, February 28, 2002 8:39 AM
Subject: ATM pitch to soft


>
> Hello everyone ;  This is my first mirror. I just poured the pitch lap in
a
> mould, using Texereau as  guide. Moderate thumb nail pressure indents the
> pitch in about 3 seconds. This is very much softer than the 10 sec. heavy
> thumb nail test according to Tex. ( I think ). Before stripping mould and
> cooking pitch again I wanted to consult the list to see if any of you had
> other options or a more precise test for pitch hardness. I,m using medium
> hardness burgandy pitch as supplied by Newport Glass.   Hoping to avoid
dumb
> mistakes, thanks.   LFD
>
>