Self Colour vs Zinc Plating vs Stainless Steel
A quick guide to understanding fastener finishes and materials
In the latest part of our ongoing guide series, we’re looking at one of the most important choices when ordering fasteners - the finish.
From corrosion resistance to appearance and application suitability, choosing the right finish can make all the difference. Below, we break down some of the most common options our customers ask about - including materials that are often mistaken for finishes, like stainless steel.
Why Use Self Colour?
Self colour fasteners (sometimes called black or plain finish) have a raw, untreated steel appearance - the way they come straight from the machine. This makes them ideal in several specific applications:
- Provides an authentic, uncoated appearance
- A light oil coating may be added for temporary rust protection
- Best suited for indoor use or where parts will be painted after assembly
- Commonly used when fasteners are being welded, as there's no coating to interfere
- Also a preferred base for further plating or heat treatment
Best for: Welding applications, components due for painting or post-treatment
Why Use Zinc Plated?
Zinc plating is the most common finish for steel fasteners. It gives the fastener a bright silver appearance and adds a layer of corrosion resistance:
- Shiny silver finish improves appearance
- Adds a protective coating to help slow down rusting
- Cost-effective and widely used in many industries
- Ideal for indoor or dry environments
- Often passivated after plating for enhanced protection and appearance
- Available in different passivation colours, such as silver or yellow (commonly known as zinc yellow)
Best for: General industrial use, dry or indoor environments
Why Use A2 Stainless (304)?
While not a finish, A2 stainless steel (also known as 304) is a widely used fastener material. It offers a natural resistance to corrosion, making it ideal for a wide range of uses:
- Excellent for indoor and moderate outdoor applications
- Common in food processing, construction, and fresh water environments
- Retains strength and appearance with minimal maintenance
- Typically non-magnetic
Best for: General outdoor use, food-grade environments, fresh water exposure
Why Use A4 Stainless (316)?
A4 stainless steel (also known as 316) is another fastener material that offers even greater corrosion resistance than A2, thanks to the addition of molybdenum.
- Exceptional resistance to salt water, chemicals, and harsh environments
- Suited for marine, coastal, and industrial settings
- Offers a longer lifespan with less maintenance
- Higher corrosion resistance than A2
Best for: Marine or coastal areas, harsh industrial environments
Other Options Available
These are just a few of the most popular finishes and materials we supply.
Depending on your project, other forms of plating and stainless grades (such as galvanised, nickel-plated, or B8M stainless) are also available.