Painting Exterior Metal - The Ultimate Guide

What Is Metal Paint?

Metal surfaces are found in multiple places around the home, inside and outside, but is an often neglected DIY job due to the nature of metal and a belief amongst many that it is difficult to paint. The reality is that it does not have to be difficult, you simply have to be equipped with the necessary information. For the effort required, painting exterior metal can be a hugely beneficial job to tick of your list as let's be honest, a rusty surface can be a real eye sore.

Understanding what paint to use for exterior metal can be a burdensome task and with summer fast approaching preparing how to revamp your metal exteriors should be a high priority on the list of jobs to do.

So, what are the available paints for metal exteriors? Metal surfaces require specific paint for them to work most effectively on the surface. As with all paint, metal paints come in two broad forms; water-based paints and oil-based paints.
Oil-based paints take much longer to dry and can be more difficult to work with, especially for the average DIY'er, however they are more durable which is a key factor when painting exterior metal. Water-based paint are faster drying and contain less VOC's, plus with developing technology, the quality of water-based paints is quickly catching up with the oil-based alternatives.

It is completely up to you which type of paint you use, however it is important to identify exactly what the characteristic of each paint type is before deciding what paint to use, as picking the best paint for the job is crucial for achieving the best results.

Exterior Metal Surfaces You May Want To Paint

There are a wide variety of exterior surfaces that often need refreshing:

• Garage doors - garage doors are a fantastic chance to stand out from the crowd and get creative
• Metal fences - metal fences are often prone to rust, which is why treating them with a metal paint is a must do job
• Metal gates - again, usually prone to rust and can make a bad first impression of your home if left untreated
• Metal gutters - painting gutters can be an often neglected job that can make all the difference to the final look of your home
• Exterior pipes - a less noticeable piece of exterior metal, however the little details can make all the difference
  
• Outdoor furniture - exterior table and chairs and other furniture is extremely quick to rust, which is why painting them so they look like new is a great DIY project to get your teeth into

Painting Galvanised Steel

Exterior metal can vary widely in terms of what metal was used. Identifying whether the surface can rust is crucially important and will ultimately decide which paint is best to use. Typically, steel is either galvanised to prevent rust or not, meaning in some cases it is important to use a rust-inhibiting metal paint, or in some cases does not need to be a consideration. Generally, most exterior metals around the house are iron or aluminium, however in some cases galvanised steel may be required to be painted.

The Best Paint For Galvanised Steel

Galvanised steel is a shiny metal surface that does not rust. Galvanised metal doesn’t rust due to a zinc layer covering the surface, which is the aspect that will take the influx of oxygen avoiding the reaction taking place within the metal and affecting it its durability.

This type of surface has the ability to be painted on without a primer using specific paints. However, it is still highly recommended to use a primer first to avoid it peeling off prematurely due to the zinc layer rejecting the paint.

Primer

Zinsser Bullseye 123 Primer

Zinsser Bullseye 123 is the perfect primer to be used on galvanised steel surfaces as it contains a biocide that will help with the build-up of any fungus, debris, or rust on the surface of the zinc layer. This primer works especially well on new metal as it sustains the painted metal surface from potential rust and ensures the surface doesn’t need to be cleaned as often. The primer can be applied without sanding and dries remarkably quickly so you can begin your exterior painting within an hour. It can be used on both interior or exterior surfaces and can be used with water-based and oil-based metal paints, making it a fantastic primer no matter what metal paint you decide to use.

Paint

Rust-Oleum Combicolour Metal Paint

Combicolour Metal Paint by Rust-Oleum is truly one of the best paints for exterior metal. It is a smooth metal paint that prides itself in being able to adhere to practically any metal surface with little resistance. Married with this, the product is heat resistant, only requires one coat and is guaranteed a perfect finish that lasts for a considerable length of time without any maintenance.

How To Paint Galvanised Metal

1. First begin by washing the surface thoroughly, making sure there is no residue on the surface as this will affect the appearance of the paint when applied.
2. After drying using either a solution of ammonia and water or even a vinegar-based solution, use a microfibre cloth to wipe down the surface. This is used to fully prep the surface and eliminate any small build-up of rust on the surface. Utilising a wire brush dipped in the vinegar may be beneficial accompanied by the application of sandpaper which will promote longevity of the paint that you will apply.
3. After cleaning the surface thoroughly leave the surface to dry completely before priming.
4. After the surface has dried applying primer is the next task. Cover the entire surface to ensure the greatest adhesion possible with the paint chosen. Allow around an hour to dry properly.
5. We would recommend using a scuttle and a paint roller to apply the paint. Cover the surface completely with the first-coat of paint, making sure it is coated evenly. Applying paint that is suitable for galvanised metal is essential for it to adhere properly.
6. Then allow the layer to dry completely before applying a second coat to ensure the perfect finish.

Painting Rusted Metal

The other condition of metal to paint on is if they metal has an abundance of rust on it. This is clearly different from galvanised metal that will encounter little to no rust to the actual metal. This will require different paint for this type of surface. If an exterior metal is not rusted, we would still recommend following the same advice for rusted metal as the surface may be prone to rust in the future. This includes aluminium, iron and steel.

The Best Metal Paint For Rust

Primer

Combicolor Anti Corrosion Primer

Rust-Oleum have developed a dedicated anti-corrosion primer that is perfect for rusted steel surfaces to protect against corrosion in the future. It has rust inhibitive properties which aids against rust, ensuring that your exterior metal surface will be rust free long-term.

Rust-Oleum Combicolour Metal Paint

Again, this product can be used in conjunction with rusted surfaces. When used with the anti-corrosion primer, it offer excellent rust-inhibiting properties, although it can be applied directly to rust if you do not wish to prime the surface. It is also a one-coat system, making it extremely easy to use for the average DIY'er. It can also be mixed in almost any colour thanks to the Painters World paint mixing service, meaning that you can completely transform your rusted exterior metal however you want.

Zinsser Allcoat Exterior

Another fantastic option is Zinsser Allcoat Exterior which is a multi-surface paint that can be applied to any UPVC, metal or wooden surface. This is a particularly good option if you are looking for a matt paint, as Combicolour only comes in satin or gloss finishes.

The beauty of Zinsser Allcoat is that it is hugely versatile, as it can be applied to almost any exterior surface. This means that you can transform all of your exterior surfaces with just one paint. That is why it is the most popular exterior paint available today in the UK. While Combicolour is the the best dedicated paint for exterior metal, if you are looking for an exterior paint for multiple projects, we would highly recommend Zinsser Allcoat.

How To Paint Rusted Metal

1. Preparation is key for painting on to a rusted metal surface. First clean the surface down using a wire brush dipped in solution to remove any unwanted surface grease, oil, dirt build up.
2. After cleaning, attempt to reduce as much of the rust on the surface as possible again using the wire brush. This will create an easier surface to apply to. Not all the rust will be able to be removed and this isn’t a problem. Use a light key sandpaper to sand down the surface to allow the paint to better adhere.
3. After removing any flaking paint and rust that can be removed, priming the surface is essential. Apply one-coat of Combicolor Anti Corrosion Primer to the surface using a paint brush, ensuring a thin and even coating.
4. After applying the primer, the process of painting can either be done using a standard paint brush or roller, depending on what exterior surface you are painting. Apply two-coats of the paint according to the manufacturer's instructions, leaving it dry completely between coats.

Things To Consider When Painting Outside

When painting exterior metal, it is important to consider:

• Rain - painting anything outside runs the risk of being affected by the weather. Paint is very particular about the conditions it can be applied effectively in, with rain affecting paint application causing it to run. Plan ahead so you have enough time to allow the paint to fully dry in-between coats, which should ideally mean you leave two days to fully complete the project.
• Paint when cloudy - many people believe the best time to paint is in the peak of summer, however this is not the case. The best weather to paint in is a mild day that is overcast, as the sun can make it difficult to paint in, not only as it will cause glare, but because when using a water-based paint, the paint will dry too quickly to get an even finish
  

Frequently Asked Questions

Q. Can metal paint be used on wood?

A. Yes, you can apply metal paint if it’s the only paint you have available. Making sure a primer is used as the first coat is key in the paint adhering. Using a paint like Zinsser Allcoat will allow you to paint both metal and wood, which is more advisable than using a metal paint on wood.

Q. Can metal paint be used on plastic?

A. Yes, using paint primer eliminates any resistance of sticking to different surfaces. It also helps prevent peeling or cracking of the paint.

Q. How much is metal paint?

A. The price of metal paint can vary, but both of the metal paints we recommend here at Painters World are between £40 to £50 for 2.5L. This is because they are high-quality and durable exterior paints that will last much longer than a standard metal paint. Contrary to popular belief, using a high-quality paint will save you both money and time, as they will require less painting to cover the surface. While it can be tempted to opt for a cheaper option, you will get what you pay for and will ultimately have to repaint the surface in a matter of years, which will double the time it took to paint and double the cost of materials.

We hope this has answered any questions you may have had regarding exterior metal painting and what the best metal paint to use is. If you require anymore help, do not hesitate to send an email to our team of experts - hello@paintersworld.co.uk. At Painters World we have a wide range of paints & decorating supplies available, so no matter the job, we've got the right tools for you. Shop our full range of trade paint today.