Cold Galvanising Spray

No, I haven't but interesting idea. I don't get much in the way of growth on anodes. However, the cell you set up with zinc on bronze is likely to consume the thin later pretty fast, assuming it sticks OK.
 
Although there is no technical information, I don't think that is the same stuff as in your first link, which is a simple zinc rich paint for use on steel as a basic alternative to proper galvanising. The US product is an epoxy probably with zinc flakes in it. The zinc does not seem to do anything as to galvanise it has to chemically bond - which it won't do to all the metals listed. never seen it this side of the pond and suspect it is a "quack" product. The Velox I linked to does work on bronze and aluminium. I did my folding prop blades 2 years ago and boat has been in the water all that time except for short lifts. Only slight slime and paint is still firmly attached. no barnacles unlike the saildrive housing which has Trilux on it. Wish I had done the drive housing when the boat was new - bit of a faff taking all the Trilux off back to the factory coating without damaging it.
 
It's just like ordinary spray paint. I probably wont even waste your money. We use it at work for steel jobs that have been galvanised and chipped/Damaged in transit. Once the job is erected we touch up the damage with that spray. Within 3 months the paint is flaking off and rust starts to appear. Ive used it on my trailer and rust appears just as quickly as if I'd used ordinary paint.

Be better off using hammerite metal paint, it's probably tougher in the long run.
 
Hot Dipped Galvanising is an alloying process. The zinc and steel form Fe/Zn alloys which are metalurgically 'welded' to the base steel. These alloys are commonly harder, thus more abrasion resistant than the steel. The quality of the alloy bonds depends on the skills of the galvaniser - if the steel is not clean - the bonding is weak. Paint , or the resins bonding the inorganic, are not strong (take a knife to any paint if you don't believe me) and forms a 'weak' bond to the substate and will wear off very quickly

Velox and Trilux are based on zinc chemicals, not zinc itself. In Australia zinc is not rated as an antifoul (though both Velox and Trilux do seem to offer some protection from fouling).

Its a bit of a worry - it is quite common for anchor makers to receive anchors back from the galvaniser and they can look a bit ordinary, mottled, chipped in transport etc - it is not unheard of for an operator to spray paint the batch with an aluminium paint - they then look lovely, and as your mother told you - looks tell you very little.

Jonathan
 
Neeves said...
"...These alloys are commonly harder, thus more abrasion resistant than the steel. The quality of the alloy bonds depends on the skills of the galvaniser - if the steel is not clean - the bonding is weak. ..."

Can I amplify a little..?
While the Fe/Zn alloys (plural as there's at least three ratios of Fe/Zn) are harder (tank carbon steel), they comprise a pretty small part of the coating. Typically 5-10 microns of a total of perhaps 80-100 microns thickness. The rest of the thickness of the coating is "pure" zinc, and that's a lot softer than steel.
Its true that galvanizing is more abrasion resistant that steel, but really only this alloy layer that is so. And that's the bot closer to the steel. The upper and major part of the coating's thickness is zinc, not alloy but that is also abrasion resistant for a different reason. Its soft, and doesn't easily get abraded. Hardness and abrasion resistance don't necessarily go together.

The quality of the bonding: I don't think this depends on the "skills" of the galvanizers, but on the practice. Its all or nothing in galvanizing: It's either cleaned properly in the acid and you get good bonding of the zinc, or its not clean and there's no bonding. But this is usually really obvious. No bonding, no coating. That is to say a bare patch. Its not that the bonding is weak, rather it's non-existent.
 
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