Zamak 3 vs Zamak 5: Zinc Alloy Selection

Zamak 3 is known for good dimensional stability, castability and surface detail. It is often used for small hardware, precision fittings and decorative parts where strength requirements are moderate.

Because it reproduces fine detail well, Zamak 3 is a natural fit for parts with small features, thin walls and visible surfaces.

• Good dimensional stability
• Fine surface detail
• Suited to small precision parts
• Moderate strength requirements

Zamak 5 contains copper, which can improve strength and hardness compared with Zamak 3. It is often selected for hardware and mechanical components that see higher load or wear.

The trade-off is that dimensional stability and finishing behavior should be reviewed against the application, because copper content changes how the alloy behaves through the process.

• Higher strength and hardness
• Suited to mechanical and wear parts
• Review dimensional stability
• Confirm finishing behavior

For decorative covers, small housings and precision fittings, Zamak 3 is usually the simpler starting point. For brackets, locks and mechanical fittings with higher load, Zamak 5 is often preferred.

The decision should consider the wall thickness, load path, assembly method and the surface finish required. In many projects the choice is confirmed during DFM rather than assumed at the start.

• Zamak 3: decorative and precision parts
• Zamak 5: stronger mechanical parts
• Consider wall thickness and load path
• Confirm during DFM review

Zinc die castings accept plating, painting, powder coating and other finishes well, which is one reason they are common in hardware and fittings.

Plating and coating can change dimensions and appearance, so the finish specification, masking and inspection criteria should be defined together with the tolerance plan.

• Zinc castings finish well
• Define plating and coating early
• Plan masking and build-up
• Inspect appearance against a sample