Re: [ATM] 20" *glass* tool

["Bob May" <bobmay@nethere.com>]

The barbell weight wants to be one of those that have the rim
ridge rather than the ellipticaly shaped ones (looking at it from
the edge) as you don't need the grinding in the middle of the
weight so much as at the edges where the ROC changes in the glass
doesn't lift the working surface off of the glass.
As to the Hydrocal and other such pourable stones, it really
doesn't matter which you use as the basic function is to provide
a waterproof pourable stone to hold the ceramic tiles which
actually do the work of grinding.  Plaster of Paris isn't a
waterproof stone so it doesn't qualify for the making of the tool
unless you seal it from the water and then epoxy on tiles
afterword which makes the whole process of making a tool way to
compled.  I just put a dam around the mirror, put some tiles on
the surface and then pour the stone in the hole.  I am usually
starting my grinding about 1/2 hour after I start mixing the
stone even tho the stone isn't fully setup and rock hard all
over.  Make your tool after you hve the basic hole in the glass
and everything will work fine.  Leave the steel and glass for
other projects.
Longer FL scopes are nice but remember that at F5, the scope will
be at least 8' tall which means you're going to need a ladder to
access the EP anywhere near the straight up direction. so beware!
The Cookbook camera is now obselete as the sensor chips are no
longer being made so something more like the Audine camera is
what you are going to build if you build one.
Bob May
bobmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net
Addresses have been munged up to keep spammers from bothering me.
replace the obvious words with the proper character.
Thank you for your understanding!

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