Pouring Silver Into A Silicone Mold

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House

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I'll be receiving a silicone mold soon that was used to make resin casts of 10oz bars and was wondering if it would be possible to use it to make silver casts? The MP of silicone is 1,414 celcius while silvers is 961 so thought it would be fine but read a few comments online saying not to do this as it would melt the silicone/burst into flames and set my face on fire.

Ideally I want a graphite or steel mold but would making a new mold in plaster and then coating it with graphite powder work just as well? Or is there a company in Aus that I could send the silicone mold to and get them to make a graphite or steel one from it? I ain't gots no tools to try and make my own.

Also, if there's anyone in Syd that makes their own molds, does their own pours etc and wouldn't mind showing me the ins and outs of it all, please PM me :)
 
I have seen jewlery being made with that type of a mold. The only thing I would think is they would be a one time use? Is it a 2 part mold or one?
 
Gold or silver jewelry?
It's a 2 part mold. It's the second one he has made, the first one got nearly 40 pours.
 
I've seen silve rings being cast from that stuff as a one part then they cut away to pull it out. He has only cast resin? What temp is that at?
 
For some reason the chemist in me is screaming no.
But I have never sen this done so the experiment side of me is saying of it.
 
Sa_bogan said:
He has only cast resin? What temp is that at?
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As far as I know he used fast cast resin but didn't ask about any other details

goanna said:
http://www.bullionumis.com/en/
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Thanks for the links but looking for a company that makes custom graphite molds where I send in the silicone one and they replicate it in graphite. Will contact them anyway to see if they can help

nickybaby said:
For some reason the chemist in me is screaming no.
But I have never seen this done so the experiment side of me is saying do it.
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Once I get a another mold, I'll pour silver into the silicone one and see what happens. The melting points of the two are significantly different so believe it'd be fine and I shouldn't end up with a face full of fire... :cool:
PS, what was that bet that you lost to your brother about?
 
House have you got all the gear?

I am in the middle of getting starting to make my mascot.
I will let you know soon. :cool:
 
Interesting question.

I looked into it as well.

No one else seems to be doing it and nothing has turned up on YouTube so I am guessing the answer is "No!"

I used to get the silicone in a tube and smear it onto modelling clay masters so I could make plaster copies. Nice and flexible for demolding.

I was thinking you could probably get a CNC machinist to machine/engrave a mold into a block of graphite.

I also saw a company who would take a 3D computer render by email, print it in wax, then cast your design into any metal using lost wax casting and post it to you. Amazing stuff.
 
House said:
but read a few comments online saying not to do this as it would melt the silicone/burst into flames and set my face on fire.
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Let us know how it goes. :)
 
I've always wondered how sand casting would go with silver.

[youtube]http://www.youtube.com/watch?v=QFLArEHFFHo[/youtube]
 
House don,t get to hung up with the melting and boiling points.

The melting point of iron oxide is very high. Put it with solid aluminium and a mild flame and you get thermite. Put molten aluminium with iron oxide and you will melt a nice hole in just about anything.

I would be worried that the silicon might react with the molten silver. Not unreasonable to form some form of silver silicide. The silver will not melt the silicon mould but rather react with it. If it is silicon dioxide mould the silver could replace the silicon for oxygen. That is very exothermic ( exciting at a safe distance). Then again i do not know as this is not my area of specialty.

Nick


The bet was a drunken bet involving a 10 pence piece and the barmaids cleavage. Needless to say I lost. I think the lifetime ban from the Pub was a bit excessive. How was I to know the barmaid was the landlord daughter? If you watch a film called Road House with Patrick Swazey you will under stand.
 
I use to make Thermite as a kid with iron oxide and aluminium powder in terricotta flower pots, put them on the roofs of stolen and dumped cars positioned above the gas tank, use a magnesium ribbon to light it and run like hell. Mischievous little scamp
 
Willrocks,

Sand molding with "black" sand as used in the video can give the finished product a lot of Inclusions (sand & or chunks of sand) in the finished product unless you know what your doing. Better to practice first with non PM until confident. Over ramming the sand (to prevent loose partials) tends to lock any build up of gasses within the over rammed sand & combined with the wrong amount of moisture in the mix can cause the two halves to separate, if weighted the top can blow out along with the molten metal, not a pretty sight up close, spectacular from a distance.

For PM Bars i think it much safer to use a Graphite mold & shot & melt in kiln as some of the mints do.

House, if you were to do it that way you'd probably want to do at least several at once to make it worthwhile. Maybe try a company doing CNC lathe work to cut out from a larger block of graphite with your design (shape) & or Logo like an ice cube tray, if that makes any sense.
 
I also remember when I sat through the pour at the perth mint, they said you lose gold into the crucible and when spent they're sent off to reclaim the lost metal

Just something to keep in mind
 
I assume that when you say silicone mold, it is something similar to the flexible baking trays that you can get for your cakes which are commonly reffered to as silicone?

If yes, then this is very different to the element silicon which as you say has melting point of 1414 C. Silicon the element is a hard brittle solid at room temp.

Silicone is very different to silicon.
 
Also remember, all liquids evaporate, including liquid metal. The hotter they are the faster they evaporate. I think the term used is 'the angel's share' when describing the lost evaporated metal. I was speaking to a metallurgist last year who informed me that I could expect a 10% loss of metal when melting it with a gas torch (oxy lpg). He wouldn't share with me his technique to minimize this loss, however I understand melting metal with an induction furnace goes a long way to reduce this. I've read somewhere that some industrial operations use argon pressurized chambers to yet further minimize evaporation.
 
House said:
I'll be receiving a silicone mold soon that was used to make resin casts of 10oz bars and was wondering if it would be possible to use it to make silver casts? The MP of silicone is 1,414 celcius while silvers is 961 so thought it would be fine but read a few comments online saying not to do this as it would melt the silicone/burst into flames and set my face on fire.

Ideally I want a graphite or steel mold but would making a new mold in plaster and then coating it with graphite powder work just as well? Or is there a company in Aus that I could send the silicone mold to and get them to make a graphite or steel one from it? I ain't gots no tools to try and make my own.

Also, if there's anyone in Syd that makes their own molds, does their own pours etc and wouldn't mind showing me the ins and outs of it all, please PM me :)
Click to expand...

shame your not in Qld :(
 
House said:
I'll be receiving a silicone mold soon that was used to make resin casts of 10oz bars and was wondering if it would be possible to use it to make silver casts? The MP of silicone is 1,414 celcius while silvers is 961 so thought it would be fine but read a few comments online saying not to do this as it would melt the silicone/burst into flames and set my face on fire.

Ideally I want a graphite or steel mold but would making a new mold in plaster and then coating it with graphite powder work just as well? Or is there a company in Aus that I could send the silicone mold to and get them to make a graphite or steel one from it? I ain't gots no tools to try and make my own.

Also, if there's anyone in Syd that makes their own molds, does their own pours etc and wouldn't mind showing me the ins and outs of it all, please PM me :)
Click to expand...

Sorry House, but this will not work. Silicone rubber is what is known as a thermoset polymer. This means that once the silicone is cured the burning temperature is now lower than the melting temperature. Essentially it is a one time irreversible moulding process due to the entanglement of long chain molecules. Silicone rubber Will start to burn at 430 deg C and will auto ignite at 750 deg C. If you pour molten silver in at 961 deg C it will instantly catch fire and start burning.
 
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