what plaster to cast a foundry pattern

[outofthefire]

just use fine casting plaster with 2 parts water 1 part pva

 

[bigegg]

just use fine casting plaster with 2 parts water 1 part pva

I've never heard of using pva with POP before...

 

[brightspark]

just use fine casting plaster with 2 parts water 1 part pva

what would be the point of adding pva its a plastic bonding agent casting plaster will go solid without and hold together

 

[bigegg]

what would be the point of adding pva its a plastic bonding agent casting plaster will go solid without and hold together

Been reading up on it.
Seems that it makes the bond very slightly flexible so resist cracking better.