Subject: impression cavities in brass, alum.

From: [email-masked] (Gary Rosenkranz)
Date: Tue, 20 Jul 93 00:03:00 -0500

My machinest told me that he made molds ( for Plastic ) by machining a
master in steel and pressing it into alum or brass in a vise or hydrolic
press or large vise. He demonstrated this technique by taking a machine
screw and pressing it between two pcs of alum. when he was done there
was a clean impression in the alum. Does anyone have any suggestions or
have any suggestions on this technique or others that i can produce
cavities in metal to make detail in molds?
    I saw a metal that has a low melting point. The book says that this
is used for drill fixtures, leveling, holding fixtures and making forms
in sheet metal. I am thinking that if the hardness of this metal is ok
that it can be used to produce an impression in brass or alum. to make a
mold. I figure that I will make an impression in plaster of the part i
want to copy. take the part out of the plaster, pour in the liquid metal
, and press the metal form into the brass. Will it work? any
suggestions? let me know.
                                Gary

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From: [email-masked] (Mark Forbes)
Date: 20 Jul 1993 07:50:03 GMT

The low-melting-point alloys are soft. It won't work. A better method might
be to make a wax model, then use plaster to create a lost-wax mold and
cast your metal in that. You can cast bronze (I think) this way. Aluminum
for sure.

Mark G. Forbes | [email-masked]
Corvallis, OR  | 503 754 3104 home phone    | Hardware R & D
"Never ascribe to malice that which can be blamed on the engineer."