Guide To Outdoor Metal Paints 2021

If there’s one space that’s had its long-awaited renaissance in the last year, it’s the garden. As the government-designated destination for fun, or the peaceful spot to step into away from the tenth zoom call, our outdoor oasis is now more important than ever. Walls and fences are the obvious makeover contenders but what about the long-abandoned metal bench; the balcony railings; or of course the garage door. Metal paint can feel a bit more overwhelming than the other exterior surfaces but get it right and it could be the perfect gleaming centrepiece for your exterior painting project.

If you’re a first timer with outdoor metal paints, or just need some tips to level up the next project, don’t worry, we’ve got you!

Can You Paint Exterior Metal?

We’re all used to painting radiators and such like inside the house, but most of us aren’t so familiar with the great outdoor metals. But how many times have you looked at the peeling garage door, or the rusting gate and thought, ‘I wonder if I could paint that’. The simple answer is YES! Of course you can, and you’ll probably save yourself plenty of pennies renovating it vs. replacing it. 

As usual, we’re going to talk to you about prep and tools being the most important part of the process. The aim of the game is to give yourself the best possible surface for all that lovely paint to stick to – trust us, we want you to have that smug-face feeling!

The obvious qualities of any exterior metal paint are that it is both weatherproof and long-lasting. Our COAT Exterior Metal Paint in Eggshell finish does both (and much more!) and is available in all our colours.

So once you’re set on your colour, grab the following, and get ready to prep:

  • Mild washing up liquid, bucket and a coarse sponge. Or pressure washer if you’ve got a big project on your hands
  • Stiff brush
  • Stepladder (if your project is taller than you are)
  • 180 grit sandpaper (check the pack of the sandpaper) 
  • Water-based exterior primer (where necessary)
  • Old sheets
  • A banging playlist – check out our COAT tunes on Spotif

If you’re still unsure – don’t worry! Give us a call and we can help you get set up.

Find Your Perfect COAT Metal Paint Colour

Surface Preparation for Painting Exterior Metal

The amount and type of prep work you’ll need to do will depend on whether you’re painting brand new metal or doing up something that’s already coated and deteriorating.

For both, it starts with a good scrub. Clean and de-grease the surface. Outdoor metals are exposed to the elements and plenty of weird stuff can layer up over time. Put your back into it, or for bigger surfaces get a jet washer involved.

surface preparation for exterior metals

Second, for the doer-upper projects, get sanding and scraping. If the cleaning didn’t get it all and there’s still old, flaky paint or rust on your surface, all of this needs to go using sandpaper or a stiff wire brush. (Don’t miss a patch otherwise this will push through your new paintwork and just be annoying). Make sure to dry it completely before moving on.

surface preparation for outdoor metals

Finally, prime the surface. For new metals that haven’t had paint on before you should use a suitable primer for the type of metal. For your upcycling projects, if your sanding hasn’t taken off all the existing paint, you should be left with a nice even matt layer, which will adequately serve as a primer to the new coat.

priming outdoor metals; surface preparation

 Once primed and dry, you’re ready to roll.

Priming Exterior Metal for Painting

A primer gives the metal a protective coating which prevents moisture getting through the paint, helps the paint adhere to shiny surfaces and enhances durability.

Find Your Perfect COAT Metal Paint Colour

As there are so many types of metals, they can all react in different ways and it’s important to get the right primer to suit. Give us a ping if in any doubt, but here are a few general principles:

  • Don’t scrimp, cheap primers have cheap ingredients. This primer needs to protect your metal, hold off the corrosion and you want it to last. 
  • Some metals like aluminium don’t love to naturally let paint adhere to their slippery surfaces, so a galvanised primer would be needed here.
  • Even if your outside surface isn’t open to the elements – maybe you’ve got a fancy gazebo – we recommend using a rust-resisting primer. Nature is pesky, it gets in everywhere! 

How to Prime For Outdoor Metal Painting

Once you’ve chosen your primer and done all your prep, you’re ready to get going.

  1. Make sure you’re in a well-ventilated area, if you’ve moved your project indoors
  2. Follow the instructions of your chosen primer product
  3. Apply 2 coats for the best protection and preparation for your COAT.
  4. Leave to dry thoroughly and don’t let the elements get to it.

The Different Types of Metal Paint Available

Let’s take a quick tour around the basics.

There are generally two types of paint - oil-based and water-based. The difference between the two is in the solvent that’s used – which is the liquid that evaporates off the paint as it dries.

The solvent in oil-based paint is typically mineral turpentine whereas, as the name suggests, in water-based paint it’s almost all water.

And why does this matter – especially when painting outside – it’s not like we’re sitting inside with the ‘paint smell’?

Well, it’s all about the VOC – the petrochemical vapours and gases that are released into the environment as the paint dries. And frankly, scientifically, oil-based paint has more of them. Much more than our low-VOC COAT paint.

Oil-Based Metal Paints are Best for Outdoor Use

True or false? When researching metal paint, particularly for exterior painting projects, you’ll most likely hear a lot about oil-based paint being the best. And that was true 20 years ago. 

But time’s moved on and innovation in paint means that water-based paint is just as good outside, with plenty more positives in the locker.

Oil-based exterior paints are known for drying to a smooth finish and continuing to harden. The drawback for this is the dry time is super slow, not ideal for projects in the great outdoors. The colour tends to change and fade over time and with hardness comes inflexibility which can lead to cracking as seasonal temperature changes. 

Find Your Perfect COAT Metal Paint Colour

Oil-based paints still have the lingering smell and are also a pain to clean up with methylated spirits rather than just warm soapy water - do yourself a favour and switch to water-based. As long as you’ve nailed the prep you’ll never look back.

Water-Based Metal Paints are Best for Indoor Use

This is still true. But we think you can see what we’re getting at by now.

Water-based paint is also great for exterior metal – especially in the way we’ve formulated COAT’s Exterior Metal Paint.

Apply nice even coats and they’ll level to a smooth finish in no time, offering long-lasting protecting from the elements. There is plenty of flex to adapt to the changing seasonal temperature and unlike oil-based paints they won’t bleach or fade, so the colour lasts. This applies to the sheen too, so that paint job looks greater for longer.

You’ll also save yourself a lot of bother with the clean up, whilst supporting a more sustainable choice. With lower VOC’s and environmental impact, water-based exterior paint from COAT is the one.

You'll need a couple of COATs over the primer - so don't worry if the first one's patchy - it won't look like that for long!

Don't believe the dinosaurs, our low-VOC water-based exterior metal paint is perfect for the job.

Second coat on - it all evens out and is ready to be a garden centrepiece.

Things to consider when choosing the best metal paint

Choosing a metal paint doesn’t have to be any more ‘heavy’ than any other paint choice (sorry, couldn’t resist).

Hopefully we’ve given you confidence in COAT Exterior Eggshell’s ability to do the job. So all that’s left is your colour choice and getting prepped. And, of course, your belief in yourself. If we can do it, anyone can.

Come on, Get your COAT

DIY vs. Hiring for Painting Exterior Metal

If you’re here with us and have made it to this part of the blog, chances are you’re on a DIY mission – great work!

For sure, you could hire a pro, but then you’d never gain all this cool knowledge and skills. 

Stick with your gut instinct, follow our steps to prep like a pro, and if you still need help, just reach out.


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