Cold galvanising spray / touch-up??

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Longshanks

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Looking to spruce up some rusty spots on an old anchor. Doesn't warrant a re-dip, but are any of the cold galavansing coatings on the market any good for the job? Preferably something in a small bottle / spray as I don't need litres of the stuff.
 
MG Duff do a cold spray. No first hand experience, but having seen an anchor treated with the stuff on their stand at a boat show, I would say it looks like good gear.
 
There's a product called galvafroid, electricians use it to protect threads on galvanised conduit, any electrical merchants should supply. you just paint it on.
Willie
 
I used to make and fit galvanized gates and railings, we used various galvanized paints to touch up modifications, damage etc. and in my opinion the galvanized paints were a good visual match but were no better than any other single coat paint (i.e no primer) at protecting from corrosion.
I would have thought that in a marine enviroment, especially on an anchor, that the galvanised paints would be useless.
Sorry! /forums/images/graemlins/frown.gif
 
I agree. I've tried on various trailer parts that get dunked in the sea. Looks good until the first wetting then the rust comes though. Might work on pristine metal before ever getting rusty though.
 
Galvafroid has been my favourite over the years. It will leave a good cosmetic finish and several coats would be required but it will not be as tough as the original.
 
Just as an update, I spoke with MG Duff today about their Zingard product, and they definitely recommend it for anchors, and generally as an alternative to hot dip coating. It's pricey at £29 for a 500ml spray can, so I'd still be interested in alternatives, but it does look like it'll do the job.
 
Most of the products described above are really zinc rich paints. Yes they work whilst the film is unbroken but they wont withstand much abrasion of the sort you get pulling an anchor in. And they will leave you with a removal problem when it comes to re-galvanisisng properly.

Hot dipping isnt expensive - check the costs locally before accepting second best.
 
I would second wotayottie galvanisers uselly have a minimum order charge HWMBOs local is £50 but the more you have done in one go the cheaper it is. If you dont mind waiting your local blacksmith can often fit it in with lots of small pieces he has been waiting to dip and devide the min order between the custermors.
 
Be wary of hidden costs at the galvanisers, if there is any rust or paint on the metal then there will be an aadditional cost to blast it clean.
And it aint cheap.
Been there , made that mistake before.
 
I work in a Harbour and our general workers use galvafroid quite a lot. We have found it to be great stuff but I don't believe it comes in small tins and it's quite costly.

You would probably be better getting it dipped. As dipping usually goes on weight it should not be too much. The company we use to do hot dipping shot blast everything first so other coatings will not be a problem.
 
So called "Cold Galvanizing" spray is actually paint with zinc particles in it.
Galvanizing prevents corrosion of steel by 2 mechanisms. One is the barrier that keeps oxygen (water, air) from the steel and stops rust. But as soon as the barrier is perforated (scratched), then it doesn't work,
The other is electrolytic. The theory is that zinc rich paints also give this electrolytic protection, but this mechanism only works where there's electrical conductivity between the zinc particles, the steel and the electrolyte (seawater).

There are a vast array of quality in zinc rich paints. One easy way to judge the quality is by weight. Zinc has a density of about 7, similar to steel, and 7 times that of water. If the can doesn't feel VERY heavy, then it probably doesn't have much zinc in it. You need over 90% Zinc in the dry film to do much good, and many paints have a lack of zinc - after all thats the expensive part.
Some have aluminium particles in also, to brighten the colour.
Good brands include Zinga, Galvafroid, Metatec.

You need to find a yachting friendly galvanizer. I know one.
 
[ QUOTE ]
Be wary of hidden costs at the galvanisers, if there is any rust or paint on the metal then there will be an aadditional cost to blast it clean.
And it aint cheap.
Been there , made that mistake before.

[/ QUOTE ]

Rang one yesterday. The guy was on holiday, but the girl in the office asked if it would need sandblasting, so this is an extra cost.

However, most of anchor is fine, just some areas that have lost their zinc, so that's why I wanted to try a patch-up first. The MG Duff Zingard is probably the best, but a little pot of Galvafroid might be easier to use if I can find an appropriate size locally. Will probably give the mfrs a call.
 
I want to try it on some deck fittings as well (which would be difficult to get off and re-galvanise) but note your comments. I've tracked down a local supplier for the 400ml tin (£12+VAT) so I'll see what happens. If it doesn't last, no great loss. Thanks for the comment anyway.

PS - did you get back to bare metal? Seems to be essential for the Zn to react.
 
I bought a secondhand anchor which had been connected to stainless swivel and so had rusted around the eye. It looked OK with our old rusty chain but we upgraded to new chain and it looked rubbish. So I sprayed it with zinc-rich paint at the beginning of the season and it's currently looking OK despite the fact that we've used the anchor a few times. I suspect that I will have to spray it again before next season but it's a job that I can do in a few minutes in-situ using some cardboard to catch the overspray. The can cost me less than a tenner from the local ironmonger.
 
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