Painting Galvanised(zink coated)Metal

[chiangrai]

HI,

To cut a long story short,I am making a charcoal burning stove that has a chimney pipe

and can be used indoors.I live high in the northern mountains.

It's going great,it's installed drawing well and ready to be painted.

I know how to prepare the steel for painting and have both spray and liquid heat resistant stove paint made in Europe and am ready to start painting tomorrow.

Here is the hitch.I just saw a YouTube video that says galvanized metal needs a special primer,The tray it stands on to protect the floor from damage has a sheet of that cheap thin galvanized coated metal you see in the hardware shops.the first 8 inches of the chimney pipe is galvanized steel and the rest of the chimney pipe is made of that glorified baking foil that the tray is lined with but it's rolled over enough times to make it safe.

It's been installed for 2 years and is working well and is safe and now I am finally getting around to painting it.

What's the story with the special primer for galvanized metal.

Is it necessary,is it available in Thailand.

I have silver couriered stove paint for the galvanized parts and matt black for the parts made of steel.The tray underneath won't be getting hot.

All advice will be greatly appreciated

Thanks.

[NeverSure]

This is true for aluminum and zinc, too. Paint won't stick to them unless it's acid etched.

The yellow aircraft primer has the acid in it, but I don't know that it's heat resistant.

If you try an automotive paint supplier, they should have what you're looking for. Various brand names are Alumiprep, etc.

The actual acid in them is phosphoric acid if you can find that. It microscopically etches the metal enough that paint will stick. You put it on, wait about 10 minutes and rinse it off. That's it.

If you can't find any of the above acids, you can use vinegar but it takes longer. You wet it with vinegar and keep it wet until it turns dark colored. Then you wash it with soap and water and rinse well. Then when dry, you can use your high heat paint.

If you don't etch it, that paint will peel off like crazy.

HTH.

Edited October 4, 2013 by NeverSure

[chiangrai]

NeverSure,

You seem to know what you are talking about.

Thank you for your help.

I will try to go down the automotive paint supplier route.the only snag is that I live way up in the mountains and a trip to the city is a long day out.

If I had a few more specifics about the products names and brands I could call the shops to see if they had it and get a local who goes to the city often to pick it up for me.

Also I only have a tiny tin of "made in England stove paint",I did not realize they had such things in Thailand..

Are there products like heat resistant silver,chrome or best of all stainless heat resistance paints on the market over here.

The more brand names and products you can give me the better chance I have of checking them out online and maybe even buying them online.

Thanks for your help so far mate,I didn't think I was going to solve this problem so easily.

I

[sirineou]

NeverSure certainly knows what he is talking about.

The Yellow aircraft primer is Zinc Chromate and is an excellent primer for galvanized metal, but as NeverSure said"he is NeverSure if it is heat resistant"

I will also confirm that in the absence of special primers vinegar works well ,

My Father used to have a painting business in the US, and as a kid I worked with him many a summer brakes from school, back then when ever painting galvanized, mental we would first wipe it down with vinegar, my hands would smell like a tossed salad still remember the smell.

I remember. once we had to spray paint galvanized chain link fence which of-course we could not wipe with vinegar, for that we sprayed silver aluminum oxide paint and it worked well

[NeverSure]

NeverSure,

You seem to know what you are talking about.

Thank you for your help.

I will try to go down the automotive paint supplier route.the only snag is that I live way up in the mountains and a trip to the city is a long day out.

If I had a few more specifics about the products names and brands I could call the shops to see if they had it and get a local who goes to the city often to pick it up for me.

Also I only have a tiny tin of "made in England stove paint",I did not realize they had such things in Thailand..

Are there products like heat resistant silver,chrome or best of all stainless heat resistance paints on the market over here.

The more brand names and products you can give me the better chance I have of checking them out online and maybe even buying them online.

Thanks for your help so far mate,I didn't think I was going to solve this problem so easily.

I

I don't know what brands might be available in Thailand or near you. They might have Thai names. I would simply ask if they have a liquid for etching aluminum and zinc as a paint prep.

If I was where you are, I'd probably use vinegar, although I can buy phosphoric acid in quarts at just about any home improvement or paint store. I can buy it as a brand name metal etch in any auto paint store.

There are stronger acids sold for the purpose of decorative etching which results in a 3-D design. That's not they kind of etching product you want. Link

You want a paint prep etch.

[chiangrai]

O.k,

I'll go with vinigar,can you run me through it one more time.

there is water coloured vinegar for sale in the local market,we have to go to tesco's

to get the light brown coloured stuff.Which is best.

Then I rub it in with a cloth I presume,

The keep it wet bit means what,come back every few minutes and apply more...

untill the metal goes a dark colour.

How dark? and how long a time frame....minutes-hours.

I really appreciate your help on this.

Thanks