zinga paint

[bcervelo]

Does anyone have experiance of using this paint (zinga)

[bcervelo]

Does anyone know of a suitable primer(sealing coat) that can be applied to zinge and sanded flat so gloss paint can be applied.

[mastcolin]

Zinga is a massively high loaded zinc dust coating.

I know of customer who trialled it on pontoons (unpainted).

I'd also heard stories of it being used on fishing boats.

I used to work for International Paint. We wouldn't recommend it under any circumstance in marine environment. You get one scratch and the zinc will turn to mush in a week in saltwater environment - making the paint all fall off in sheets.

Also zinc causes a lot of one pack primers(ie alkyd) to saponify (sorry for tech term) ie it makes the paint lose adhesion - just drive along a lot of roads and see garage doors with huge bald areas where paint has fallen off the galvanised door.

Of course now maybe they (and any other coatings manufacturer) have more experience - but whether they ever suggest/recommend something other than their own complete systems is unlikely.

Speak with whoever's paint you are wanting to use. Most tech-desks will give you answer on latest thinking.

ps yes some cars are now 'zinc coated" but a) it ain't pure zinc, it is passivated by addition of stuff like cobalt b) car's don't have stress of 200microns of paint on top.

Zinc blast primers are on about 10microns. The paint normally holds on by virtue of blast profile - and these primers are best applied under factory conditions ie clean, dry, very tight spec - most things lacking by those wanting to use zinga.

I imagine the stuff ain't cheap. Is it any cheaper than blast and high quality epoxy anyhow? Done well this any going to need any serious repair untill you are lying on your deathbed.

[MikeJohns]

mastcolin

A few notes on your post.

The word is "disbonment" you are partially correct it should not be used immersed but it is very good above the waterline, in any position where the base coating is compromised the zinc rich primers will prevent rusting with only a small amount of disbondment around the broken coating. On the other hand rust will spread considerable distances very quickly if fed with electrloyte and air coupled with deep pit corrosion and unsightly rust bleeds.

For steel work boats the zinc rich epoxy primers are an ideal choice. For vessels receiving a more gentle handling there are various topcoats that work well over Zinga and other rich primers.

zinc coated carage doors are painted as cheaply as possible with a finish coat without the etch primer, zinc coated steel is quite different to zinc rich primers.

[mastcolin]

Mike

I have no doubts on what you say.

You sound like you're talking from real life experience at least. (but one swallow etc)

My only fear, and to be honest at time at International we only just started looking at test panels of the stuff, was that is was so massively loaded with zinc and pretty bereft of any resin it scared us from previous experience.

It isn't a zinc rich primer ie zinc fully encapsulated in some sort of resin system eg epoxy, alkyd. - it's just super majority zinc (from my knowledge). Certainly when I was with them, we were treating it as galvanised, which is why I made comment on garage door, not zinc rich ie you've gotta use some sort of etch primer not just sand and apply further primer.

I'd go back to my original final answer. Does it actaully work out any cheaper? And then place in risk factor.

I don't want to sound like I'm being unnecessarily negative, I've just seen enough nightmares...on peoples dreams. (eg rust 'convertors", 'no blast primers", mixed schemes etc etc)

Having been in field as tech sales, I'd just say "tough luck" to you if it went wrong.

As I said, speak with the tech desks. It's what you pay for.

ps I absolutely no longer work for any paint supplier! I'm on the dirty end now painting a 35m yacht.

pps I don't want to disappoint a lot of you there but a lot of the "tech" stuff in paint is marketing lead as opposed to science. You can load some paints with zinc and they'll perform no better than another resin and inert pigments without. eg undercut/disbondment has more to do with adhesive and cohesive strength of film than the pigment load make up. Hopefully the won't come after for me for admitting this...I'll lock my door tonight in case...

[MikeJohns]

We have had good success with a thin application of clorinated rubber base zinc rich primer followed by a decent epoxy. The trick is not to use too high a build of the zinc. It sounds like that may be the problem with peoples application of Zinga.

I absolutely agree that much of the paint marketing is hype. Part of marketing is setting the price, Some significant leading brands have a bit of a reputation in the industry for marketing to fairly ignorant worried boat owners and setting a high price while telling them they are getting a higher quality product than the competitors offer.... all rubbish of course.
Just look at the thinners content of some of their epoxies !

There is nothing magic about epoxy and one manufacturers is usually as good as anothers.

Only experience really shows what sticks in the long term. With any change in paint system the result should be tested for adhesion before applying to the hull .