ATM Softening pitch

["Art" <mock47@accessbee.com>]

Hello everyone,

I am new to this list and have been reading the posts with interest for
several weeks.  Some years ago a pair of 10" x 1" mirror "flats" came into
my possession.  I have recently decide to fabricate a F/7 mirror from one.
I have constructed the Dobsonian scope and ground the mirror through 5
micron.  A plaster and ceramic tile tool was made to preserve one of the 10"
flats.

The point of process has been reached whereas it is time for constructing
the pitch lap.  I have cast a plaster lap tool using the dammed mirror
(hopefully this figure of speech is not too appropos) and plaster of paris.
This brings several questions to mind which I hope someone will kindly
answer:

1. I have one kilo of Gugolz 74, I have read to soften it with mineral
spirits and also never to use mineral spirits, but to use turpentine
instead.  I have also read to use bee's wax.  I have read turpentine for
"burgundy" pitch and mineral spirits for "black" pitch, such as Gugolz.
Which is best?

2.  Should one be able to perform an adequate Foucault test on a 5 micron
ground mirror?  Or is it usually necessary to have some polishing?

3.  I am thinking of heating the pitch out in my back yard using low heat
 from a propane camp stove.  Is this suicidal?  Can it be done safely if one
is carefull to keep the flame low and go slowly?

4. Other than perhaps teflon, is there any easily acquired substance to
which pitch will not adhere?

Would it for instance be feasible to rout several 1" x 12" x 3/8" deep slots
in a 1x12, soak the slotted areas in motor oil or some sort of release
agent.  Pour the pitch to the thickness desired, remove it before it became
brittle and perhaps cut it into 1" squares using a hot knife or such tool?
Because my plaster tool is cast to the curve of the mirror it might be
simpler to heat and stick these squares than deal with other methods of
channeling the lap.

Finally, during the fine grinding the ceramic tiled surface of the tool
seemed to be as smooth as the glass of the mirror.  This begs the question
is there any possibility of using ceramic as a mirror media?

I didn't mean to make this post so long. . .
Thanks for any help.

Arthur Mock
Fresno, CA