Hi folks, from looking up a few specialist paint suppliers I see that vinyl paint is the type of paint specified for use over zinc treated surfaces, typically "high build vinyl paint". Does anyone know what it is about vinyl paint that makes this the case? Just curious.

Don't have a clue as to why, but one wanders if they are refering to Poly vinyl acitate or poly vinal cloride? PVA is prety common water based sealer for aplications were one needs to unify the absorbability of surfaces ans stain sealing. 

I think it's manor coatings? Am pretty sure Brundles is now supplying it so give them a ring.

Technically galvanized steel is coated with zinc chromate to stop those streaks of white growth from marring the look of the surface. A paint with an oil based solvent will react with this alkaline surface and form a soap like substance that delaminates the paint layer.

A product like colourbond corrugated iron is not zinc chromate coated and is lightly media blasted on its way to the paint shop. The old style acid/ZnCr/resin primers had to be mixed onsite and used within a few hours and were recommended to be used in a spray booth due to health effects.

I have tried to get the Urethane type coatings here with no luck at all.

I don't know the technical /chemical answer to your question, I have a memory of the paint history as far as blacksmiths go...

A German company called Weigle und Schmidt made a paint favoured by many mainland European smiths. WS-plast M4200

http://www.ws-lackchemie.de/2012-03-28-15-21-37/ws-plast-dickschicht-m-4200-en.html

Brian Rourkes company marketed "Vinylast" paints which they also claimed would adhere to hot dipped galvanised surfaces.

When they went bust Brundles took over marketing the Vinylast paints.

The range of patinas that Rourkes sold all had WS in their part numbers the same as Weigle und Schmidt so I concluded it was all the same stuff, cheaper direct from Weigle und Schmidt if you are buying quantity.

Alan

Thanks folks. B.T.W Alan, I remember you mentioning before that you mix graphite in with your paint, is that with vinyl paint? Where do you get graphite from?

*sigh* Brundles. Every time I hear that name I get this awful earworm mash-up in my head...a varition of that Ant & Dec song "let's get ready to rumble"...becomes "let's get ready ready, let's get ready ready, let's get ready to Brundles". Now it an annoy you too.

Do a search on here I have posted it before.

my long and wittily amusing response was forbidden and lost in the ether.

Alan

P.s.

ah it allowed me to post. 

Longer answer, no graphite with vinyl. I use an eggshell or semi Matt synthetic enamel. Trimite is the brand leader. I use one from the local paint factory/ retailer.

Rocol Foliac flake graphite 4 B from memory ....search my earlier posts. 

Or from a graphite wholesaler David Hart up near Redditch.

If you are passing you can have a tub from my sack at favourable rates of course! 

Edited August 26, 201510 yr by Alan Evans

ah yes, Vinylast was the brand I was thinking of that Brundles sells, and Manor Coatings also does a direct to galv one too.

Cheers folks. For what it's worth I discovered a company in Burgess Hill called Ace Coatings South that do vinyl paint in any RAL or BS colour you want. Then all you have to do is make the client realise ironwork doesn't have to be BLACK!