Plating & metallizing · finish comparison
Hot-Dip Galvanizing vs Zinc-Flake Dip-Spin Coating
Hot-Dip Galvanizing and Zinc-Flake Dip-Spin Coating are both electroplating & electroless plating finishes; hot-dip zinc is the lower-cost option ($$).
Hot-Dip Galvanizing
Electroplating & electroless plating · $$ · instant quote
Hot-dip galvanizing immerses fabricated steel or hardware in molten zinc to form a thick sacrificial alloy coating.
Zinc-Flake Dip-Spin Coating
Electroplating & electroless plating · $$$ · instant quote
Zinc-flake is a non-electrolytic zinc/aluminum-flake basecoat, often with a topcoat, for fasteners and high-strength steel.
When to choose which
Choose Hot-dip zinc
Choose Hot-dip zinc when thick outdoor protection on structural steel is acceptable.
- Thick sacrificial protection for outdoor steel
- Covers edges and accessible interiors
- Metallurgically bonded iron-zinc alloy layers
Choose Zinc flake
Choose Zinc flake when high-strength fasteners need thin non-electrolytic protection.
- Common systems target 600–1000 h to red rust
- Typical 6–15 µm total coating
- No electrolytic hydrogen charging
What the numbers say
- Hot-dip zinc is the lower-cost option ($$).
- Zinc flake is the thinner coating (6–15 µm), so it disturbs tight fits less.
- Hot-dip zinc is conductive; Zinc flake is insulating.
Scores side by side
Each score is 0–100 against every finish in this catalog. Corrosion is derived from salt-spray test duration and surface hardness from the finish layer's Vickers hardness where a measured figure exists; a finish that leaves the base metal's own surface is not rated for hardness. Cosmetic, lubricity and cost are FabDigit's engineering assessment. Scores and typical figures are screening data, not matched side-by-side tests or service-life rankings; ASTM B117 is a controlled salt-fog method, not a field-life prediction.
| Score | Hot-dip zinc | Zinc flake |
|---|---|---|
| Corrosion resistance | 90 Excellent | 85 Excellent |
| Surface hardness / wear | 42 Fair | — — |
| Cosmetic quality | 32 Low | 35 Fair |
| Lubricity | 22 Low | 55 Good |
| Cost | 28 $$ | 42 $$$ |
Key numbers
| Property | Hot-dip zinc | Zinc flake |
|---|---|---|
| Thickness | 45–100 µm | 6–15 µm |
| Surface hardness | 70–250 HV | — |
| Salt-spray test duration | 800–1,500 h | 600–1,000 h |
| Max service temperature | 200 °C | 180 °C |
| Electrical | Conductive | Insulating |
| Colours | silver gray, matte gray | silver gray, black |
| Relative cost | Standard ($$) | Premium ($$$) |
| Added lead time | 4–10 working days | 4–8 working days |
| RoHS | Compliant | Compliant |
| Instant quote | Yes | Yes |
Bold marks the side that is ahead on a row where more (or less, for cost and lead time) is better. Ranges are the typical specification window; the drawing call-out fixes the class.
Which materials take each finish
| Material family | Hot-dip zinc | Zinc flake |
|---|---|---|
| Steel | Yes | Yes |
| DMLS / SLM | No | Limited |
| Stainless Steel | No | Limited |
Specifications and drawing call-outs
Hot-dip zinc
- ASTM A123 — Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products
- ASTM A153 — Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware
HOT-DIP GALVANIZE AFTER FABRICATION PER ASTM A123; PROVIDE VENT AND DRAIN HOLES; CHASE M12 THREADS AFTER GALVANIZING
Zinc flake
- ASTM F1136 — Standard Specification for Zinc/Aluminum Corrosion Protective Coatings for Fasteners
- ISO 10683 — Fasteners — Non-Electrolytically Applied Zinc Flake Coating Systems
ZINC-FLAKE COATING PER ISO 10683, 8 µm MIN, SILVER, INTEGRAL LUBRICATED TOPCOAT; 720 H MIN TO RED RUST PER ASTM B117; COEFFICIENT OF FRICTION 0.10–0.16
Hot-dip zinc vs Zinc flake — frequently asked
What is the difference between Hot-dip zinc and Zinc flake?
Hot-Dip Galvanizing and Zinc-Flake Dip-Spin Coating are both electroplating & electroless plating finishes; hot-dip zinc is the lower-cost option ($$). Zinc flake is the thinner coating (6–15 µm), so it disturbs tight fits less. Hot-dip zinc is conductive; Zinc flake is insulating.
When should I use Hot-dip zinc instead of Zinc flake?
Choose Hot-dip zinc when thick outdoor protection on structural steel is acceptable. Conversely: choose Zinc flake when high-strength fasteners need thin non-electrolytic protection.
Is Hot-dip zinc or Zinc flake cheaper?
Hot-dip zinc is the lower-cost finish ($$ against $$$ for Zinc flake) among the finishes FabDigit quotes. Both are priced per part with a lot minimum; the exact figure appears on the instant quote once the part is uploaded.
Which lasts longer in salt spray, Hot-dip zinc or Zinc flake?
Hot-dip zinc. Hot-dip zinc is rated 800–1,500 h and Zinc flake 600–1,000 h in neutral salt spray (ASTM B117 or the qualification hours of the governing specification). The figures are for the finish as specified on a clean, properly pre-treated substrate; sealing, thickness class and substrate alloy move them.