Dow Magnesium Coating — Pakenham, Victoria
Dow Coating For Magnesium
The factory finish for magnesium engine cases, covers and hubs. Chromate conversion coating that stops magnesium corroding and gives back the correct gold-bronze look — the detail that separates a real restoration from a repaint.
★★★★★5.0 on Google15 reviewsMagnesium specialistsCorrect factory finishTrade work welcomeSend-in Australia-wide
Rare In AustraliaVery few workshops offer it
Factory CorrectGold-bronze conversion finish
Stops CorrosionMagnesium protected
Australia-WidePost your parts in
What It Is
The Finish Magnesium Left The Factory With
Magnesium is light, which is why manufacturers used it for engine covers, clutch cases, ignition covers and hubs on race and production bikes. It’s also chemically hungry — left bare it oxidises into a grey, chalky mess, then keeps going and starts eating into the casting itself.
The factory answer was a chromate conversion coating. It isn’t paint sitting on top of the metal. It converts the surface of the magnesium itself into a stable, corrosion-resistant layer, and it leaves that distinctive warm gold-bronze tone that anyone who knows these bikes recognises instantly.
That’s why it matters on a restoration. You can paint a magnesium cover silver and it’ll look tidy for a while. Dow coat it and it looks correct, it stops corroding, and a judge or a buyer can tell the difference across a shed.
Very few workshops in Australia offer Dow coating. If you’ve been told your magnesium cases can’t be done properly, or you’ve been quoted paint as the only option, this is the alternative.
A Note On Colour VariationEvery part finishes slightly differently depending on the specific alloy composition and the condition it arrives in. Unlike paint, where you pick the exact outcome, Dow coating produces a natural finish ranging from dark brown through to gold-bronze. That variation is a characteristic of the authentic process, not a fault — it’s part of why the finish reads as original.
What We Coat
Magnesium Parts We Take On
If it’s magnesium and it came off a bike, it’s a candidate. Single covers or a full engine’s worth.
Clutch & Ignition Covers
The most commonly magnesium part on a vintage two-stroke, and the one most often ruined by oxidation or a previous respray.
Engine Cases
Full case halves where the original castings are magnesium. Sealing faces and bearing bores masked and protected.
Hubs
Magnesium front and rear hubs brought back to the correct factory tone, ready to lace with new spokes.
Water Pump & Sump Covers
Smaller magnesium castings that spend their life in water, mud and chain fling, and corrode first.
Triple Clamps & Yokes
Where a model used magnesium in the chassis. Stamped numbers and casting marks stay legible.
Race & Works Components
Factory and works parts are far more likely to be magnesium. Getting the finish right is the whole point on a bike like that.
Not sure whether your part is magnesium or aluminium? Send a photo. Magnesium usually shows a distinctive grey chalky oxidation rather than the white powdery corrosion you get on alloy — and if it’s alloy, Cerakote or vapour blasting is the right answer instead.
Scope
What’s Included, And What Isn’t
Included
- Degrease and full surface prep
- Removal of oxidation and old coatings
- Masking of threads, bores and sealing faces
- Chromate conversion coating applied
- Even factory gold-bronze finish
- Parts bagged individually for return
Quoted Separately
- Disassembly and reassembly
- Bearing and seal removal or refitting
- Corrosion pitting repair or welding
- Thread repair and helicoils
- Clear topcoat over the conversion layer
- Freight to and from the workshop
Parts need to arrive stripped — no bearings, seals, studs, rubber or plastic. Deep corrosion pitting can’t be coated away, so if a casting is badly eaten we’ll tell you before you spend money on it.
Why It Matters
Paint Hides It. Dow Coating Fixes It.
It Stops The Corrosion
Paint over corroding magnesium and the corrosion keeps going underneath until the paint lifts. Conversion coating treats the surface itself.
It’s The Correct Look
That gold-bronze tone is what a period-correct bike is supposed to have. Silver paint on a magnesium cover is the tell that gives a build away.
Thin Film, No Tolerance Change
A conversion layer is microns thick. Sealing faces stay flat, bearing bores stay round, stamped numbers stay readable.
Judged Shows And Resale
On a concours bike this is a scoring detail. On a bike you’re selling, it’s the difference between “restored” and “tidied up”.
How It Works
Drop In, Or Post It In
Because so few workshops offer this, most of the magnesium we coat arrives by freight from interstate.
01
Send Photos
Tell us what the parts are, what bike they’re off, and how bad the corrosion is. We’ll confirm whether they’re magnesium and whether they’re worth coating.
02
Strip And Pack
Bearings, seals, studs, rubber and plastic out. Wrap each casting separately and pack the box so nothing can move in transit.
03
Prep And Coat
Degreased, oxidation and old coatings removed, threads and faces masked, then the conversion coating applied to an even factory tone.
04
Back To You
Bagged individually and freighted back, or held here if the next step is an engine rebuild or a restoration with us.
Questions
Dow Coating Questions
What is Dow coating?
Dow coating is a chromate conversion coating for magnesium. Rather than sitting on top like paint, it chemically converts the surface of the magnesium into a stable corrosion-resistant layer, and leaves the distinctive gold-bronze tone that magnesium parts had when they left the factory.
Why does magnesium need coating at all?
Magnesium corrodes aggressively when left bare. It goes grey and chalky, then starts eating into the casting itself. Manufacturers coated it from new for exactly this reason, and any magnesium part that has lost its coating is actively deteriorating.
Can’t I just paint magnesium instead?
You can, and it will look tidy for a while. The problem is that corrosion continues underneath the paint until it lifts, and silver paint on a magnesium cover is immediately obvious to anyone who knows the bike. Conversion coating treats the metal rather than covering it.
What colour will my parts come out?
Somewhere between dark brown and gold-bronze. The exact tone depends on the specific alloy and the condition the part arrives in, so unlike paint you don’t pick the outcome. That natural variation is a characteristic of the authentic process and part of why the finish reads as original.
How do I know if my part is magnesium or aluminium?
Magnesium typically shows a grey, chalky oxidation, where aluminium goes white and powdery. Magnesium is also noticeably lighter for its size. Send us a photo and we’ll tell you — if it’s aluminium, vapour blasting or Cerakote is the right process instead.
Which parts are usually magnesium?
Clutch and ignition covers are the most common on vintage two-strokes, along with some full case halves, hubs, water pump and sump covers, and triple clamps on certain models. Factory and works race parts are far more likely to be magnesium than production equivalents.
Can badly corroded magnesium be saved?
Sometimes. Surface oxidation cleans up and coats well. Deep pitting where the corrosion has eaten into the casting can’t be coated away, and on a sealing face or a bearing bore it may be terminal. Send photos and we’ll tell you honestly before you spend money on it.
Can I send magnesium parts in from interstate?
Yes, and most of what we coat arrives that way, because very few workshops in Australia offer Dow coating. Castings freight cheaply — wrap each part separately and pack the box so nothing moves.
Do you coat alloy parts at the same time?
Yes. Most engines are a mix, so we vapour blast the aluminium castings, Cerakote anything that needs colour, and Dow coat the magnesium — all in the same building, so it’s one lead time and one freight leg instead of three.
Get Started
Book Your Coating In
Pick a day to drop the parts in, or note that you’re posting them. Tell us what the parts are and what bike they’re off.
Dow Coating Enquiry
Choose “Other” and describe the parts. Posting them in from interstate? Pick any date and note it in the message.
Get Your Magnesium Right
Drop them in or post them in. 18 Rapid Way, Pakenham VIC 3810, Monday to Friday 9am–5pm — and Australia-wide by freight.
0423 963 402