Re: [CAD_CAM_EDM_DRO] Machineable wax - answer to Ian's question

Hi all! This is Smoke,
I'm using my nieces computer to access my email so I won't have 4 or 500 emails
to look at when I get back home.

If you can make you model oversize (to allow for both wax and metal shrinkages),
you can make a mold from acraglas, bisonite or some other form of castable
polyester. This mold is filled with wax using a jewelry makers type of wax
injection machine. This method works well for SMALL parts...such as those watch
cases...but won't work well for large parts due to variable rates of wax
shrinkage in large part sections.

What to use for the original pattern would depend on how your going to machine
it. I'd prefer a very hard high temp machineable wax or aluminum. Make the
part in three pieces if your concerned about really needing the square corners.
Some of those square corners aren't really required as the pins for holding the
wrist straps don't get all the way into the corners anyway. Also, having
slightly filleted corners will help prevent stress cracks if you investment cast
the parts. If you make the pattern from hard machinable wax, and the parts fit
together very closely, then you can glue the wax pieces together using a
cyanoacrylate glue (instant glue) and won't need to worry about clean up
(required if you weld the wax parts together.


Another way of making the mold....perhaps an even better one....would be to use
the high temp. wax and make the mold from a vulcanizing rubber. There is a wax
avbailable thru a place in Canada now that DOES NOT MELT under the temperatures
encountered during the vulcanizing process. I'll have to look it up when I get
home next week.

Smoke