Screw Finishes Explained

The coating on a screw decides how long it survives corrosion, how it looks, and how it drives. Here is how the main finishes compare and when to use each.

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Every fastener C S Fasteners ships can be supplied in a range of finishes. The right choice depends on the environment (indoor, outdoor, marine, automotive), the look you need, and your budget. Below is a plain-English comparison.

Finish comparison at a glance

FinishCorrosion resistance & typical use
Clear / Blue ZincLow-moderate (≈72–120 h salt spray). Economical, bright, indoor general use.
Yellow ZincModerate. Zinc with yellow passivation — better than clear zinc, common in automotive.
Black Oxide / PhosphateLow (with oil). Matte black look, primer base, mild indoor corrosion control.
DacrometHigh (≈500–700 h). Zinc-aluminium flake, no hydrogen embrittlement, silver-grey.
Geo-metHigh (≈600–1000 h). Chromium-free, eco-friendly alternative to Dacromet.
RuspertVery high (1000 h+). Multi-layer zinc + ceramic + topcoat, heat & chemical resistant.
NickelModerate + decorative. Bright, used in electronics and visible hardware.
ChromeDecorative + hard. Bright mirror finish for premium visible fasteners.

How to choose

  • Indoor / dry: Clear or Yellow Zinc is cheap and sufficient.
  • Outdoor / humid: Geo-met or Dacromet for long life without plating embrittlement.
  • Marine / automotive / high heat: Ruspert for the toughest environments.
  • Visible / consumer products: Nickel or Chrome for appearance.

A note on hydrogen embrittlement

High-strength, case-hardened screws can fail by hydrogen embrittlement after electroplating. Zinc-flake coatings like Dacromet and Geo-met are applied without electroplating, which avoids this risk — important for hardened self tapping and chipboard screws.

Finishes we offer

C S Fasteners supplies all of the above across our machine, wood and custom screw ranges. Tell us your environment and we will recommend the most cost-effective finish that meets your salt-spray requirement.

Ready to order?

Send us your specification, finish and quantity — our export team replies within 24 hours with pricing and lead time. White-label and custom options available.

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