The specific catalyst used in sand casting depends on the type of binder being employed. However, based on the provided reference material, when phenol-formaldehyde resin is used as a binder in sand casting, benzene sulfonic acid (BSA) is the preferred catalyst.
While toluene sulfonic acid (TSA) can also be used, it generally produces less desirable results compared to BSA.
Therefore, to reiterate:
- Preferred Catalyst for Phenol-Formaldehyde Resin: Benzene sulfonic acid (BSA)
- Alternative Catalyst (Less Desirable): Toluene sulfonic acid (TSA)
It's important to note that various other binder systems are used in sand casting (e.g., sodium silicate binders), and these would employ different catalysts or hardeners altogether. The answer above specifically addresses phenol-formaldehyde resin binder systems.
