Helpful audience!

Today, I made my first spinn-casting with zinc.

It was just a first test shot to see what I can do wrong and what I did
already do wrong.
So the mold was just a plaster mold [1] and the zinc was just some scrap
zink sheet metal for roofing. That zinc proofed to be good enough and I
will use up all the rest before going to the costy zinc I ordered.
At least, the spin caster was a success. I had no other motor at hand,
so the disk is rotating with nearly 1400 RPM. Direct driven! The disk
has a diameter of 12". I thought more g-force = better surface. It
seems, that that is right. No problems with vibration, as the frame
where all the suff sits in is quite heavy.
The first casting was a (partial) success, some detail very good, other
bad. But that only where I had bubbles in the plaster. Also a partial
failure, because I didn't melt enough zinc. I have to cut the inlet (in
the center of the disk, because to much is cooling down there and
remains there and doesn't flow down into the mold.

So I will make some mods, add a brake to stop the disk spinning and add
shielding and paint.
Will put pics and explanations to my HP. This time in English, so you
don't have to babelguess about what I have written in Kraut-Language.
Will take some days, but I will keep you informed.

Oh, the silicone is damned expensive! 1kg (2 pounds) about 50 EUR, that
are 60$. :-( OK, it withstands 500°C (930 F), zink poring temperature is
400°C (750F). But that stuff is to expensive for playing around.
I will think about to put the rubber in some supporting form to save
some rubber.


[1] that showed to be my newest invention "lost plaster casting".
Also, I baked it too long in the oven. It broke in 3 parts over
night. Some super glue fixed that.
I didn't get the castings out of the mold, so I broke it apart.
It was some wothless casting anyhow.

Nick
--
Motormodelle / Engine Models:
http://www.motor-manufaktur.de
Ellwe 2FB * VTM 87 * DLM-S3a * cubic
more to come ...