Heavy + precise. Light + everyday. Both hot-injected.

Zinc's lower melt temperature allows longer fill time before solidification, better filling of fine detail, less thermal stress on tool. Result: finer features, tighter tolerance, better surface finish. Aluminum's higher temperature means faster solidification, more aggressive tool wear, less fine detail capability. For intricate decorative parts: zinc. For bulk structural: aluminum.

Zinc tools last 500K-1M shots typical. Aluminum tools 100K-300K typical. Tool cost same ($30K-100K+). Per-part tool cost: zinc significantly lower. Over production life of 1M parts: zinc tool cost $0.03-0.10 per part; aluminum $0.10-0.50 per part. Factor into total cost comparison. For very high volumes, zinc economics favor even more.

Per unit weight: aluminum significantly stronger (specific strength 120 vs 42 for zinc). For weight-critical applications (automotive, aerospace), aluminum better. For applications where weight doesn't matter (door hardware, locks, fittings): zinc's density is actually preferred (feels solid, stays put).

Zamak 3 (ZA-3): most common, general purpose. Zamak 5 (ZA-5): 1% copper for slightly higher strength, better creep resistance. Used for more demanding zinc applications. Zamak 2 (older): 3% copper, obsolete. ZA-8, ZA-12, ZA-27: higher aluminum content for bearing applications. Most zinc die casting: Zamak 3 or 5.

A380: most common die cast aluminum. 8-9% Si, 3-4% Cu. Good castability, moderate strength. A383: similar but lower iron — better paint/plating. A360: 9-10% Si, 0.5% Cu. Better corrosion resistance. A383 preferred for decorative applications; A380 for general industrial. All available from die cast suppliers.

Zinc: electroplates beautifully (chrome, nickel, brass). Standard for decorative hardware. Paint/powder coat also works. Aluminum: anodize possible (specify die cast alloy compatibility), powder coat standard, paint with proper primer. For premium decorative: zinc with chrome or gold plating. For industrial/automotive: aluminum with powder coat.