ATM atm plaster tools

[Wolfgang Birkfellner <birkfell@merlin.pap.univie.ac.at>]

Hello ATMs!
After reading a lot of posts on the use of plaster for tools, I 
remembered 
a technique I was introduced to in a mirror making class at Vienna. We 
used thin plate glass tools (about 6mm thick) for our small 6 in. 
mirrors, 
and these plates were glued onto a concrete tool by means of epoxy. I do 
not know what kind of concrete was used, but I think that Hermann 
Koberger (who introduced us to mirror making) used a special cement that 
is 
known here in Austria as rapid cement - I do not know the ingridients of 
that stuff. It is sold in small quantities (about one kg) and is 
completely cured in less than two hours. Craftsmen use it for small 
repairs 
or for attaching something in a brick wall. It seems as if Hermann 
had a mold (I would use a wooden form covered with lots of talcum powder)
and made a 1 in. thick round brick he coated with laquer afterwards. Note 
that the top of the brick was very smooth and not painted. I 
have recently found that 13 year old tool and it is still in a working 
condition. I do not know how that stuff is called in the USA, but I am 
sure a bricklayer would know that kind of agent. Be aware that you do 
not have a lot of time to complete the tool since this stuff settles 
within a few minutes. It does not shrink or expand. 

I do not know wether the different brands of plaster you have mentioned 
mean a similar type of cement, and I hope that someone understands my 
pidgin-english :) ....
Wolfgang Birkfellner