Need help on metal casting and more

[kramt]

What molding material do you use for metal casting? Is RTV silicone good enough for this? What is the metal used by games workshop for their metal products?

Is plaster of Paris a good alternative for RTV silicone to be used for molding for a regular resin casting?

Thank you

 

[Einion]

Originally posted by kramt
What molding material do you use for metal casting? Is RTV silicone good enough for this?

Some RTVs are heat-resistant enough to use for limited casting of metal, but for any larger numbers your really want a vulcanised rubber mould.

Originally posted by kramt
What is the metal used by games workshop for their metal products?

It\'s a type of low-melt alloy, generically called \'white metal\'. These are essentially a kind of pewter (without lead).

Originally posted by kramt
Is plaster of Paris a good alternative for RTV silicone to be used for molding for a regular resin casting?

A good alternative? I don\'t think so.

I think you could cast resin in plaster moulds but it\'s not ideal and I don\'t know what you\'d use as a mould release.

Einion

 

[airhead]

If you use plaster, you have to bake all the moisture out of it first. Otherwise, when you put in that nice hot molten metal, the moister in the plaster suddenly vaporizes and you get a plaster grenade with molten metal bits.

Jewlery guys use lost wax and plaster for a one-shot cast.

 

[kramt]

Thank you for the reply guys. Any advice is welcome

 

[kramt]

Another follow up question:
Is latex mold a good alternative for RTV silicone rubber for resin casting? Thank you

 

[airhead]

generally - no.

Two part pourable silicone rubber or ureathane rubber will outlast a latex mold.

What part of the world are you in?

What are you trying to cast? How many parts you want to pull from the mold? How detailed is the part?

All of this makes a difference.

 

[Einion]

Originally posted by kramt
Another follow up question:
Is latex mold a good alternative for RTV silicone rubber for resin casting?

The thing is, in case this isn\'t obvious, you can cast resin in a latex mould but there are (can be) other considerations as airhead mentions above so the \'good alternative\' part is a bit subjective.

Einion

 

[kramt]

Please forgive me for my ignorance, but this would be the first time I\'m going to cast something. I am planning to cast a certain part of a Warhammer 40k infantry model (i.e. the head). I am actually looking for a cheaper good if not better alternative for RTV silicone. How good is latex mold for a 40k sized detail?
Thank you

 

[airhead]

Why not just buy the heads as bits? It will be cheaper than setting up a mold and casting.

Plus, you won\'t have any detail lost from a recast - not to mention any copyright issues.....

Just asking...

You still haven\'t said how many parts you want to pull?

Micro-Mark has a quart of rubber for $36 -

You need a pot to melt lead (or non-lead lead) in - don\'t use the good cookware.

Metal or resin - lead is easy - hit the tire shop for some wheel weights - but they smell of burnt rubber when you melt them down. Resin gets costly and has a shelf life.

Time to make the mold, etc.