Ceramic Mold For Casting Fine Silver

[kadriver]

I would like to cast some small pure silver figurines (2 to 4 inches tall) using a split ceramic mold.

The two halves of the mold have alignment stubs and are then clamped together for pouring.

Does anyone on the forum have experience that could be shared using ceramic molds of this type to cast silver?

I did a search of the forum with negative results.

The alternative to using ceramic would be sand casting (as for as I can tell).

I would especially like to hear about any negatives.

Thank you.

kadriver

 

[Lou]

I think you'll find the ceramic molds to be a one time gig. Better off to take the figurine and make a mold in RTV silicone and inject wax into that, sprue up and then invest, vacuum out bubbles, burn out cast, and de-vest.

Could you post a picture of the figurine?

Might try backyardmetalcasting's forum.

 

[kadriver]

Does the ceramic deteriorate that quickly? Thanks for the heads-up.

 

[Harold_V]

I expect the mold will self destruct upon pouring, and it may do it violently. That, of course, depends on what the mold is made of, and if it's intended to be used for molten metals. My concern is that the material from which it's made may not be good at all with thermal shock, and may contain enough moisture to become a bomb. My money says you should abandon that idea. Could be wrong (but I don't think I am!)

Harold

 

[niteliteone]

The only casting I have heard of that uses "Ceramic Molds" is ceramics casting itself, making ceramic figurines.
We have a large ceramic factory a few miles from where I live, "Duncan Ceramics" and I have watched them do this process.
Anyway, that type of ceramic mold would definitely break when the heat of the molten metal hit it. I have heard of making molds from plaster material like "Plaster-of-Paris", but again it would be a one time use.
I would do something like a lost wax type of mold, where you can make many molds from one master. Many jeweler supply shops will sell the casting mixtures

 

[Palladium]

If you can use graphite for the mold then you might try these folks they make 3D molds. http://www.ebay.com/sch/weaverind/m.html?_nkw=&_armrs=1&_ipg=&_from= Not sure of how intricate you need the mold, but i have had them make me molds before that are pretty detailed.

 

[Dan Dement]

We are manufacturing Jewelers who specialize in Platinum & Palladium so we have a little casting experience. I know of no one in my industry that uses Cermaniic molds. Not saying it will not work but lots of unanswered questions. What does the figurine look like? What level of resolution are you trying to achieve? How big are the models? Aree they hollow? What type of weight?

Personally, I think you are far better off just getting someone set up to do it and sub it out. It just all depends on the details. The Devil is always in the detail!

Good Luck,
Dan

 

[kadriver]

Here are the pieces I am trying to cast.

The ceramic mold looks like a bad idea.

I have had a Corning ware casserole dish explode on me once.

I was drying some cement silver, turned the heat on high and left to do something else with the intention to turn it down to low once it heated up, forgot about it while doing another task.

I heard a POP and the dish had busted into tiny pieces, the silver spilled out and had to be cleaned up.

This should be proof enough that ceramic combined with molten metal in not a good combination.

I may just start learning the lost wax method for casting these pieces, or maybe try sand casting.

Thanks for the input.

 

[Lou]

I feel like lost wax will give you the best results for the minimum investment.

Kerr Satin Cast is sufficient for an investment.

 

[RikkiRicardo]

Lou
Yes you can do it with lost wax but you can also buy sand cast pieces
http://www.mechanicalengineeringblog.com/wp-content/uploads/2012/01/01-lost-wax-method-gated-patterns-chess-piece-manufacturing.jpg
but i will go with lost wax
it is the best way to go
yes more equipment but it's the best way then only polishing just like silver jewellery

RikkiRicardo

 

[Dan Dement]

Just depends on now many you are trying to do and if you want them solid. No big problem to make a silicon mold of the actual piece and make waxes for casting. You can always hollow out the center to cut down on the weight. So, you need to make molds of the King, Queen, Rook, Castle, Bishop, and Pawn. Cast the White's out of Silver or Sterling. If you add about 5% Pd, you will find the silver will not tarnish nearly as bad. Now, for the Blacks, you might wannt to alter the metal. Perhaps something along the line of 50% Copper/50% Silver. If it was me, I would get a caster to do it for you as I don't think you can do it yourself cheaper. Happy to give you a couple of names.

DDan

 

[kkmonte]

You could always plate the silver in gold for the "black" pieces. Check this set out..

http://www.ebay.com/itm/Chess-set-32-piece-Oriental-inspired-design-Solid-Silver-Gold-P-/111012971529?_trksid=p2054897.l4275

 

[Palladium]

You could always plate the silver in gold for the "black" pieces. Check this set out..

http://www.ebay.com/itm/Chess-set-32-piece-Oriental-inspired-design-Solid-Silver-Gold-P-/111012971529?_trksid=p2054897.l4275

That guy is off his rocker to want $15,000 for that! :roll:

 

[Harold_V]

So, you need to make molds of the King, Queen, Rook, Castle, Bishop, and Pawn.

You left out the Knights. Rook and Castle are one and the same, although they are properly addressed as a rook.

Harold

 

[grance]

Sand cast with a very fine casting mix would be how I would try.

 

[Lou]

I have far, far, far more experience sand casting than I do lost wax. I have sand cast silver, brass, bronze, lead, magnesium (in petrobond), zinc and zamak, cast iron, aluminum bronze and some additional pot metals.

I can tell you, you can get great surface finish with sand casting (with fine olivine petrobond, I could get the date on a quarter), but even using the finest green sand, it won't be the same as what you can get from an investment casting via lost wax.

 

[MysticColby]

you can cast in ceramic, but it's not typically a repeatable mold. more like lost wax but with ceramic skin to get finer detail. basically, the wax is painted with a thin layer of ceramic slip (I'm sure the choice of which clay to use makes a huge difference), then left to dry a bit, then the whole thing is encased in plaster or similar, then you burn out the wax and heat to remove water from the mold. I hear this results in finer detail than just lost wax.
My first casting attempt I used a 2-part plaster mold. I made about 3 aluminum castings before I decided it would be too much work to clean up a casting made with it again. basically, every time you remove a casted piece, a bit of the mold will come off. you might get lucky and get a few decent pieces, but #2 and up will always disappoint you.

I normally do my silver castings in lost wax with Americast. It's very similar to plaster, but will withstand high temperatures better. much less cracking and shrinkage. very good detail. I recall that there are a couple different types of it, but I forget which I got. I think I got it from this website, but I can't find the other options... http://www.contenti.com/products/casting/164-514.html

 

[grainsofgold]

For the black pieces I would cast them in palladium and leave them in the oven when you take them out they will have a nice dark patina on them -

Silver is a PITA to cast unless you do it often - sub it out-

GOG

 

[Irons]

Does the ceramic deteriorate that quickly? Thanks for the heads-up.

Investment Casting. Also: Lost Wax process. Folks have been doing this for Thousands of Years.

https://en.wikipedia.org/wiki/Lost-wax_casting

http://www.ehow.com/way_6463143_homemade-investment-compound-casting-bronze.html

Using a Vacuum Pump to get the bubbles out of the Casting Plaster is a big time-saver. I use a Dessicator which has a Vacuum Tabulation and metal cage to prevent flying glass in case of failure. There are plastic ones on the market that also combine the ability to dry the mold and extract the bubbles. If I were doing it from scratch, I would go with plastic, but I got a good deal on a Pyrex one with safety cage about 35 Years ago and it hasn't broken yet.