Common Questions

Frequently Asked Questions

Detailed answers to common technical and commercial questions about hard anodising — including materials, specifications, and turnaround times. Operating from West Auckland.

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Technical QuestionsMaterials & SpecificationsCommercial & PracticalIndustries & Applications

Technical Questions

Hard anodising provides strong corrosion and wear resistance, electrical insulation, and stability at high temperatures. Unlike paint or powder coat, the coating is UV-stable and won't degrade. Black dyed finishes are available.
No. A 60µm coating is roughly 50% penetration into the base metal and 50% buildup above the original surface. This is different from plating or paint, which sit entirely on top. The exact ratio varies slightly with alloy but stays close to 50/50.
Yes. We need firm electrical contact throughout the process, so each rack contact point leaves a small uncoated mark. Tell us where the non-critical surfaces are when you drop off your components, and we'll rack accordingly to minimise the impact.
Type III Class 1 (undyed) produces a green-brownish coating with a matte to semi-matte finish. Type III Class 2 is dyed black. The coating follows the underlying surface finish — components machined to 1.6Ra give a smooth anodised finish, while rougher machining gives a rougher result.
Yes, but it's not simple. The process needs caustic chemicals and removes material from the base aluminium. If you're considering stripping and re-anodising, talk to us first — you may lose dimensional tolerance.

Anodising is an electrochemical process that converts the aluminium surface into aluminium oxide — the coating is part of the metal, not a separate layer on top.

Powder coating is a polymer film applied to the surface. Anodising won't chip or peel, handles continuous temperatures up to 200°C, and is UV-stable. Powder coating offers more colour options and can hide surface imperfections better.

Sulphuric acid anodising (Type II) runs at room temperature and produces a 12–25µm coating.

Hard anodising (Type III) runs cold (0–5°C) at higher voltage, producing a 60µm coating that's significantly harder and more wear-resistant. Type II works well for architectural and decorative applications. Type III is for components under high mechanical stress.

Materials & Specifications

No. Anodising only works on aluminium and magnesium alloys. Steel, stainless, brass, and copper need different surface treatments. If you're not sure what material you have, send us a sample and we'll check.
The 5000, 6000, and 7000 series perform consistently well, as do 355 and 356 cast alloys and 319 die-cast. For best results, keep copper content below 3.5% and silicon below 5%. 6061 and 6082 — widely used in New Zealand fabrication — both anodise reliably.
Yes. Magnesium has an excellent strength-to-weight ratio but corrodes easily without treatment. Anodising significantly improves corrosion resistance, making it ideal for aerospace and motorsport applications where weight matters.
Type II (standard anodising) produces a 12µm coating. Type III (hard anodising) produces a 60µm coating that's significantly harder and more wear-resistant, suitable for components under mechanical load or in demanding environments. Type II is more cost-effective and works well for architectural extrusions, balustrades, and decorative applications.
Yes, for 355, 356, and 319 alloys. Cast components often have porosity that can appear as dark spots after anodising. Die-cast components with high silicon content (above 8–10%) anodise poorly, producing a grey or streaky finish. Send us a sample if you're unsure.
The 2000 series (high copper content) has strong mechanical properties but is difficult to hard anodise, producing a darker and less uniform finish. If you need hard anodising for structural applications and you're choosing the material yourself, go with 7075 instead of 2024.
It helps. If you know the alloy, tell us. If you don't, send a sample component and we'll evaluate it — alloys that look identical can anodise completely differently.

Commercial & Practical

Cost depends on component size, batch quantity, and coating type. Type III costs more than Type II due to longer processing time and thicker coating. Production runs get better per-unit pricing than small batches. Call us on 09 836 8889, or send us your component dimensions and quantities for a quote.

Type II usually takes 5–7 working days. Type III hard anodising takes 7–10 working days. Faster turnaround may be possible depending on the current tank schedule. Get in touch early if you're working to a fixed deadline.

Yes. Our West Auckland facility handles large components for marine, aerospace, and industrial work. Send us your dimensions and we'll confirm whether it fits.

Faster turnaround may be possible depending on current workload and tank schedule. We'll do our best to accommodate time-critical work, but can't always guarantee it. Get in touch early.
No hard minimum. Small or one-off jobs cost more per piece because of fixed setup time. Single prototype components are fine. Larger production runs get better per-unit pricing.
Pickup and delivery is available for large orders and regular clients. For smaller jobs, dropping off at our West Auckland facility is usually easier. Talk to us about logistics when you book.

Industries & Applications

Main sectors are marine fittings and hardware, defence and military equipment, aerospace components, medical instrumentation, automotive performance parts, and precision tooling. Hard anodising is specified wherever you need strong wear resistance and corrosion protection in demanding environments.
Yes. Marine work makes up a large part of what we do across Auckland. Type III hard anodising performs reliably under saltwater exposure, making it ideal for boat fittings, cleats, winches, and deck hardware. We also offer Type II Marine Class (25µm) for semi-hard applications where full Type III isn't needed.
We can meet a range of aerospace specifications. For specific mil-spec or AS/NZS standards, send us the documentation and we'll confirm whether we can certify to the required standard.
Yes. Hard anodising is widely used on medical instruments because it's corrosion-resistant, biocompatible, and stands up to repeated sterilisation cycles. The hardened surface resists wear from clinical use.
Type III hard anodising achieves 1000+ hours in neutral salt spray testing (ASTM B117) when properly sealed. Type II typically achieves 500–1000 hours depending on coating thickness. If you need a specific salt spray performance, tell us the target hours and we'll spec the process accordingly.

Further Enquiries

Call us on 09 836 8889 or send us your component details for technical advice or a quote.

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