Zinga on a steel boat

[Roadkill]

Hello,

I've just been given a quote for my steel Gulfstream 42 shotblasting, and they included the price of two coats of Zinga cold galvanising.
I was wondering if anyone has any experience of this product? Is it any good? Any reccomendations for topcoat paints? Also, will I still need antifouling (I assume so)?

Thanks,

Dave.

 

[AndrewB]

Don't know about this particular product, but have cold-galvanised deck fittings and anchor in the past and would not bother again. However this system was used in the past with some success in expert hands. For example 50 years ago Moitessier's steel yacht "Joshua" was zinc-coated by the Meta boat company and he swore by it (see "A Sea Vagabond's World, Boats and Sails, Distant Shores, Islands and Lagoons").

These days though I think it is mostly used on aluminium hulls. For mild steel a two-part zinc-rich epoxy is now universally acknowledged as the best primer, and though it is expensive should keep rust at bay for at least 10 years if properly applied. It can be overcoated with almost any other paint. Typically polyurethane is used above the waterline, antifouling below.

Hot-galvanised steel can be painted easily enough, though with a somewhat rough finish. I don't know about cold- galvanised though, nor can recall any paint manufacturer's recommendations on this.

There have been some threads about cold-galvanising on the Boatdesign forum (http://www.boatdesign.net/forums), which might be helpful.

 

[Ships_Cat]

As Andrew has said 2 pot epoxy primer straight onto the steel is the usual and the coating manufacturers I have have spoken to do not now recommend zinc rich primers for the underwater parts of boats.

Personally, I would not even consider using a cold galvanising coating.

Any of the major paint manufacturers supplying paints to the marine market (eg International, Jotun, some of the various industrial coating manufacturers) will give you a good specification using their coatings. If the boat is being blasted then I suggest getting the coatings professionally applied by one of the paint manufacturer's recommended applicators - the labour involved is not that great and you will end up with the specified coating thicknesses, etc ensuring you get best mileage from the investment in the paint.

John

 

[boatmike]

Totally agree but would add DON'T shotblast until you are ready with the first coat of primer which should be applied directly afterwards. Leaving primer coating even hours after shotblasting will allow oxidation to form, in fact shotblasting is the ideal preparation for rust!

 

[Roadkill]

Ok,

Thanks for the advice everyone, I'm convinced. I think I'll go with a 2 part Hemple system.

Dave.

 

[rogerthebodger]

Covered steel hull prep here

 

[ean_p]

I know a guy who used Zinga though admittedly not on a shot blasted hull....it failed miserably within the first season.......and the boat had very little use!