Temperatures of figure molds?

[Temperance]

Hi all,

Quick question here -- can anyone tell me the temperature that vulcanized rubber molds are \"baked\" at when they\'re created? I obviously don\'t mean the room-temperature vulcanizing rubber, but what companies like GW would use.

The point is that I need to cast a figure that might become a master for a mold, and I want to make sure that the metal I use doesn\'t have too low a melting point. Is 160 degrees F or 280 degrees F high enough, or am I going to need to go to the 500+ degrees F stuff?

 

[Chrispy]

Hey Peter: I\'ve little expirence casting, but what I remember from the product info of casting metals is that 160 F melts with a candle, so I don\'t suggest that one. 280 F seems what you want, as it melts with a butane torch and molds last longer with a cooler metal. The 500 F and up metals are mostly Lead, and that can be dangerous if you don\'t ventilate, wear a mask, goggles, and gloves.

As for molds, most room temperature vulcanizing silicone rubber will stand temperatures of up to 600 F, so whatever you decide it will do. Hope this helps, and check out Micromark for pamphlets and books on casting!

 

[Temperance]

Oh, I\'ve got the RTV rubber (from micromark, actually!) and that\'s what I plan on using.

The problem I have is that I (will soon have a figure that probably won\'t withstand the hotter vulcanizing process (I think it has a plastic support rod or something like that) so I need to make a cast so it can be produced. Do you think a metal figure (made from the 280 F metal) can withstand the vulcanizing process?

There\'s a ~575 degree lead free metal that I could use. (It\'s called Crown Pewter (92% tin)) I\'d rather use the lower melting point stuff.

 

[Chrispy]

Kay, lemme get this straight: you\'ve got a metal figure that\'s made from 280 type metal and you want it to survive a vulcanizing process to make a mold.... I\'m not sure what temperature you need to mix the mold at, or if it just gets hot when you mix it together, but rubber doesn\'t conduct heat very well. I would say it should be okay, but to be 120% sure you could got with the 575. But wouldn\'t it be better if you try and make copies of the mold using the original (I assume green) fig?

 

[Temperance]

That\'s the heart of the problem -- the orignal figure is mostly greenstuff, but it unfortunately contains a substance that won\'t survive the warmer temperatures of the vulcanizing process. (I think it contains a plastic rod or something like that; I don\'t know, I didn\'t make it.)

What I need to do is make a duplicate of that original mostly greenstuff figure that can survive a higher temperature vulcanization process, and I\'m wondering what metal I need.

Would a butane torch be warm enough for the 575 F pewter?

 

[Sand Rat]

Not sure about the other parts of your question, but the Butane torch should be more than ample for the 575 degree stuff - just check with the guys at your local hardware store to be sure - or you might try MAPP gas ( same type of torch - just burns hotter)

 

[MrKlipp]

Are you sure you have your products straight? You said you are getting RTV rubber, which stands for room temperature vulcanizing. This does not require or generate a lot of heat, and will work fine with greenstuff and plastic.

 

[Temperance]

I have my products straight. The problem is someone else will be producing the mold for mass production, and they need a figure that can withstand the warmer vulcanization process. I have a figure that will not withstand the warm vulcanization process.

I plan to use the RTV rubber to make a single cast in metal of the original figure so I can send it to be mass produced by someone else.

I guess I\'ll just use the Lead-free Crown Pewter (92% tin). It melts at approx. 575 degrees F. We\'re all pretty sure that works.

 

[MrKlipp]

Ok, I misread you. That does sound like it should work.