You are purchasing 10 Lbs of binder to mix with
50 lbs of your own VERY FINE SAND.
To make 60 lbs of casting sand add this Binder to 50 LBS OF VERY FINE SAND.
Then Add ~5% by weight of clean water.
Mulling:
Machines are made for mulling, but they are expensive.
We have found that the following technique works quite well.
We use one of those plastic cement mixing tubs available at your local Home depot or Lumber yard:
Mix with a shovel and walk around in the sand scraping with your feet
until it is well mixed and the sand is uniformly coated with the clay.
Your casting sand should look like this when you are done.
clipped from: cgi.ebay.com 
