Greensand Casting
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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
- K-bond- the open source oil sand - [4], hint from [5]. Another link to PDF of formula - [6]. See Definitive Article on K-Bond.
- Petrobond - good for novices - [7]
- Ebay - 5 lb - $20 - [8]
Casting Companies
- Commercial airset sand casting - [9]
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 - [10]