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Casting silver with stones


#1

is there a way to sand cast or investment cast where i may cast
glass into the silver without the glass breaking thanks also looking
for info on sand casting tufa and investment casting by hand thanks
so much rovah


#2

Hi Rovah,

is there a way to sand cast or investment cast where i may cast
glass into the silver without the glass breaking thanks also
looking for info on  sand casting tufa and investment casting by
hand 

Unless you’ve got a special glass I’m not familiar with; glas can’t
be cast in place without shattering. The thermal shock of the hot
metal on the cold/cool glass is too much for glass.

Most inclusion free & unfilled diamonds & corundums can be cast in
gold & silver. There may be other stones that can also be cast in
place, but it’d take a few experiments & probably some broken stones
to find the correct ones & to develope the technique.

Diamonds have also been cast in place in platinum using a nely
developed investment.

Dae


#3

Stones or glass?

I’ve cast glass in silver a bit… a couple things to keep in mind
and you should be fine:

  1. Use ONLY borosilicate glass: Pyrex, Kimex, Simax, etc… Any
    softglass (lead/soda) will melt or deform during burn out, if it
    doesn’t it will pop or explode when the metal hits it. Nothing is
    absolute, but that’s my experience with soft glass.

  2. Make sure that when you do your burn out, that the glass will
    stay in place. Glass does not bond well to investment, and I’ve had
    plenty of marbles break loose. I make my own glass, so I find that
    putting a short piece of rod attached like a punty works great to
    hold the marble (or whatever) in place till after the cast, then it
    can be snapped off and fire polished…

  3. Don’t go over 1200F on your burn out, and make sure you cast
    while the flask is still hot… that seems obvious maybe, but letting
    the flask cool for over a minute will not work. Glass cools very
    rapidly compared to metal and investment, too cool and you’ll break
    the glass.

  4. After the cast (this sucks…) you cannot quench your flask, You
    will have to carve off the investment by hand with a little chisel
    and a wire brush and some stone files. If you have a high pressure
    steam blaster for taking off investment it should be ok but I haven’t
    tried one. Just work in the smallest flask you can for the piece, the
    results can be worth it.

otherwise, I’ve had better than 50/50 success with casting glass in
place. I don’t know if you are making or buying your glass… but if
you are making it, you’ll learn what colors and what structures are
strong enough to survive a spin casting. Thin things don’t do well
with 2 oz of hot metal slamming into them, marbles and blobs are
fine. Avoid anything with solid Green in it, as most green boro glass
is unstable. Anyways I’d love to hear how it comes out =)

Oh and about casting… Tim McCraight (spelling?) has a book on
Practical Casting, that goes over small scale tufa and steam casting,
something you may wanna look at. I have the book, it’s been a great
resource.

Good luck, -Doug Harroun


#4

You may want to try the newest PMC3 product which will be introduced
at Tucson. It sinters at lower temperatures which will make it
useable with glass. It is VERY expensive though . . . something
like $27.00 for a quarter of an ounce.


#5

I do not know of any way to cast glass in place. However, while at
Rio Grande’s Catalogue in Motion show last weekend I was shown a new
type of PMC - PMC3, that I was told was developed specifically to
address the issue of firing PMC with glass in place. It fires at a
lower temp than previous versions - as low as 1110 degrees F. I have
no experience with firing PMC and my only experience in working
glass is from carving it; just trying to pass along new info.

Epaul Fischer
Gryphon Song Creations
http://GryphonSong.com