Greensand Casting

Basics

• There are 2 main Sand Casting methods, which combined make up about 40% of all casting processes: Greensand and No-Bake Sand Casting
• No-Bake uses Sand and a Thermoset Plastic Mixture of the relevant Plastic Precursors and Catalysts which cures around the sand, holding it in place, in a similar manner to Composite Materials
• Greensand Casting Can Have Various Binders which will make it either:
  • Self-Hardening (Minor Overlap with No-Bake Sand Casting
  • Gas Hardening
    • An example is when Sodium silicate is used. Carbon Dioxide is used to "Cure" the mold after forming
  • Thermohardening
  • This Classification is from a Reference to a Book by a User Discussing this in the Sand Casting Wikipedia Page
• The Terms "Water Bonded" and "Oil Bonded" are also used in the context of Greensand Formulations, especially at a smaller scale

Technique

• Comprehensive diagram of all casting types - [1]. MIG Casting is not included. Binders can be clay, chemically setting binders, and polymerized oils (motor oil)
• No-Bake (airset or precision sand) casting - use a binder with sand. [2]
• Types of Binders - [3]

Off the Shelf Greensand Sources

• Petrobond - good for novices - [4]
• Ebay - 5 lb - $20 - [5]

Casting Companies

• Commercial airset sand casting - [6]

Greensand Formulas

Theory

• You Will Have:
  • Sand ( Grain Size , Sand Type , etc all have their effects)
  • Your Binder(s)
    • In terms of non-Sodium Silicate or No-Bake
  • Small Amounts of Additives for more Specialized Greensand Formulations
    • Reducing Agents
    • Cushioning Material / Insulating Agents

• One here, includes oil and bentonite - [7]

Misc DIY/OS Recipes

• From Backyardmetalcasting - [8]
• Sand + bentonite, mulled - [9]

K-Bond

• K-bond- the open source oil sand - [10], hint from [11]. Another link to PDF of formula - [12]. See Definitive Article on K-Bond.
• "K-Bond is named for Kent State where it was developed by one of Tom Cobett's Students.

It is an almost smokless oil bonded foundry sand for casting zinc, aluminum, brass, bronze and iron."

Internal Links

• Open Source Metallurgy Construction Set

External Links

• Wikipedia Page on Greensand Casting