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How to Paint Galvanised Metal

Are you looking at your galvanised metal surfaces wondering where to start with your paint work? Let us help! It doesn’t have to be a difficult task to keep galvanised metal surfaces looking great for as long as possible.

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The problem with painting galvanised metal is that the surface when new is very shiny and smooth, making it difficult for paint to stick to the surface. It also has surface contaminants (oils, greases, residues, etc.) left on the surface from the manufacturing process that interfere with the adhesion of paints. You need to tackle this with the right products and preparation to make sure it stays put. You’ll notice on surfaces that haven’t been treated properly, that the paint will peel and blister very quickly.

Priming and Preparation

If you want to paint a galvanised surface, you need to prepare it properly with thorough cleaning and a good primer where required.

New Surfaces:

Thoroughly wash with an alkaline cleaning solution (something like Rust-Oleum Mathys ND14 Cleaner Degreaser) using a Scotch-Brite pad to scrub the surface. Once cleaned, thoroughly rinse down with fresh water and allow to dry. Now you’re ready to prime with something like Rust-Oleum 3202 Galvinoleum Primer. This primer is a one step solution that can stick to nearly any smooth surface including galvanised metal. Apply it with a brush and its ready to recoat within 30 minutes with a compatible topcoat.

Alternatively, many professionals will skip this time consuming process by treating with Mordant Solution, or T-Wash as it’s often called. This is an acidic solution of a copper salt for the pre-treatment of clean zinc surfaces to provide a good key for paints which would otherwise show poor adhesion. Once treated with Mordant Solution the surface can be painted as normal and no special adhesion primers are required.

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Weathered Galvanised Surfaces (12 months +)

If the galvanised metal you’re intending to paint has been left out in the elements for 12 months or more then the tricky cleaning process of removing all the manufacturing contaminants has been carried out for you. All you need to do is clean any dirt and grime that has built up on the surface and apply a ‘direct to galv’ paint like 1805 High Build Vinyl Finish. This paint produces a high build, tough and weather resistant, flexible sheen finish that is often chosen by tradesmen due to it’s fast drying times.

Previously Painted Galvanised Surfaces

You’ll want to remove any old flaky paint with a non-metallic abrasive (sandpaper) and wash down as you would with new galvanised surfaces (see above). Once it’s ready, you should apply Rust-Oleum 3202 Galvinoleum Primer to any bare galvanised surfaces.

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Painting and Decoration

It is possible to paint galvanised metal in the full range of industry colours available, without flaky and peeling paint. Once you’ve prepared your surface and primed it if required, you can feel reassured that your paint will look great.

To make sure it really has staying power, you need to use a high quality topcoat designed for these kinds of surfaces such as Rust-Oleum 7500 Alkythane.

Rust-Oleum 7500 Alkythane comes in a wide variety of colours, including metallic and can be produced in a gloss finish or a satin finish. Apply this paint by brush, roller or spray and you’ll have a fantastic looking surface, that is protected and can last. If applying to galvanised surfaces that have been prepared with Mordant Solution then prime first with Rust-Oleum 1080 High Build Primer, this will ensure excellent corrosion protection and lasting flexibility.

We hope you’re ready to get painting – don’t forget we’re here to help if you have any questions!

10 comments

  1. Looked at many sites but nobody seems to cover the best way of preparing old galvanizing in this case a trailer that has been in salt water and is probably 20 years old. It has a sort of encrustation on the surface and a few areas of rust but not much.
    I have some Scotchkote epoxy 152LV paint to use only £124 a pot so I don’t want to make a mistake in prep.

    • Good afternoon John,

      The 3M Scotchkote Epoxy Coating 152LV is not suitable to be applied to galvanised substrates, none of the 3M heavy duty systems are. If the trailer is going to be put back into the water, the surface will need to be abrasive blasted as a minimum. Have a look at the 3M Scotchkote Epoxy Ceramic Surfacer FG 512 (Kit) Data Sheet to give you some idea on the surface preparation on salt impregnated surfaces.

      Best regards.

      Mark

  2. I have two dorma windows in the front of my house. One has a copper roof, which is now green with age. The other has a more traditional lead roof. I would like to paint the edge of the copper roof to match the colour of the lead – just will look better. Could you please advise how to prepare the copper surface and which paint am I best that will give a long life. Thank you.

  3. Hi there, I have an old galvanised tin wash tub that I want to turn into a sink for a utility area. I would like to keep the external weathered finish but need to prep and paint the interior with a gloss finish for easy cleaning – what would you recommend? Thank you

  4. I’m roofing a small outhouse with new galvanised corrugated steel sheeting. I’d intended to wash off any grease with a mild caustic solution before installing. When dry and after installation I was intending to paint with a couple of thick coats of solvent-based bitumen. Anyone see any problems. please?

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