Application of resins and curing agents

The core factors affecting the resin-to-hardener ratio mainly fall into these categories: 

Resin type (furan, phenolic, epoxy, unsaturated polyester, etc.) 

– each with different curing mechanisms, resulting in completely different ratios.

Hardener type (acidic, alkaline, room temperature/medium temperature) – the dosage varies greatly.

Ambient temperature and humidity: High temperature → faster curing, hardener can be reduced appropriately;

 Low temperature → slower curing, hardener needs to be increased appropriately.

 High humidity also affects curing speed.

Required curing speed: For tight deadlines and quick demolding → 

higher hardener ratio; For long-term operation and slow curing → lower ratio.

Size and wall thickness of castings/products:

 Thick, large parts tend to accumulate heat and cure quickly → less hardener;

 Thin-walled, small parts dissipate heat quickly → more hardener is needed.

Usage strength and performance requirements: Inaccurate ratios can lead to: 

insufficient strength, brittleness, softness, blistering, sticking to the mold, and numerous air bubbles.

The condition of the raw sand and the process: Sand temperature, old sand recycling rate,

 and sand mixing equipment efficiency will all fine-tune the actual optimal ratio.