Overland Defender Chassis HDG Vs. Zinga Vs. External Coating

Hi guys,

I am stripping down my Defender to prep it for my Africa Overland.

I am down to 3 options:

-Hot-Dip Galvanising
-Zinga (Cold Galvanising method): Zinga is an active zinc performance coating which works in conjunction with the metal beneath whereas paints are only passive barriers. Regardless of how thick paints are applied, they remain as barriers. Once they are breached corrosion sets in immediately. If the Zinga layer is sufficiently damaged to expose the base metal below, the steel would form a layer of surface rust but no corrosion would take place beneath it.
-External Coating paint Epoxy Mastic 121: (winner of the Winner of the Classics monthly 3 year test http://www.rust.co.uk/filestore/3 YEAR TEST SUMMARY PDF.pdf) Epoxy Mastic is a two component Epoxy paint composed of nanoscale corrosion protective pigments in short chain molecules with very low surface tension. This allows the paint to flow into all of the pits and troughs on the steel's surface, ensuring a tough penetrating primary bond. This is the best kind of bond you can get with a paint finish.The high build epoxy forms a super strong protective barrier over the corrosion inhibiting pigments that hug the steels surface Excellent penetration and adhesion within a high build coating equals exceptional mechanical strength.

What are the pro's and con's of each of the 3 alternatives? what would you guys choose and why?

Thanks,
Simone

The info you posted within the Zinga description rules out the Epoxy Mastic 121 for me. I would go for HDG, get the steel clean and up to temperature to allow the zinc to bond effectively.

I've used Zinga on a pair of axles and some other bits, overcoated with their Zingatarfree and then 2k gloss. They're not under the vehicle yet, but have been in a relatively damp area, and I've deliberately not touched up the scratches through to metal made during re-assembly. Getting on for a year on and they're still rust free. Not exactly a proper test.

I did follow all the instructions to the letter. Blasted to the right standard on a hot dry day and painted within an hour or so.

Thanks @boguing for sharing how you applied it - the Zingatarfree is recommended for use in duplex systems with ZINGA for application on structures in immersion or embedded in soil - what are the benefits of applying it on the axle? what's the purpose of applying on top of it the 2k gloss ?

Thanks a lot

I think that you've misread me. The 2k gloss is the top coat.

I felt that the Zinga itself was a little too soft for something that was going to get sprayed with wet gravel from time to time, so spoke to the tech chaps at MGDuff (makers of Zinga) and they suggested the tarfree. It's pretty thick stuff (fairly sure that it's a polyurethane-type product like many others) and feels very tough once cured. It's a dark grey, almost black, and I wanted a lighter colour, hence the gloss over the top.

My chassis wasn't galvanised when I bought it from Ricards', and once it's completely finished it'll be galvanised then, but I'll be painting that with the tarfree and gloss as well. Partly to make it last even longer and partly because I don't really like the look of ageing zinc.

Cool - is this Zingatarfree something like a Jotun epoxy mastic 87? A very hard paint applied on top of the Zinga to give it a longer lasting protection?

No idea what Jotun 87 is like, but yes, a tough coating.