I've heard of this, but for full cast gold? Maybe I'm in the dark here, does anybody else do this?
Works for all castings - Its a method to determine the amount of alloy regardless of type.
All castings will have porosity because of the shrinkage that occurs during cooling. All you can do is control where the porosity finally ends up at.
The alloy amount is just one of those control factors.
Just curious - When you cast the final one, did you still have a button?
Casting multiple units was a thorn in my side for a long time
I eventually went back to basics
I use an 8 gauge runner bar
10 gauge feeds (around 6mm in length) to each pattern
and on a thick pontic I run another sprue lead from the pontic down to the runner (18 gauge)
Oh - and all my type III castings I still use a gypsum bound investment
The castings are spot on every time.
Everyone I work with laughs at me - says they have quicker methods -
Heat it and it will cast, all for one investments etc...
Im all for change and new methods when it works- but sometimes I just chuckle as they are
'RE'waxing that bridge due tomorrow morning