Metal Primers, Intermediates and Undercoats

The range of rust inhibiting primer and undercoats for metal available at Rawlins Paints are compatible with products from the range of topcoats available by the same manufacturer (please refer to product datasheets for product combination recommendations) and provide the perfect start to any painting project. Using the correct metal primer with not only give superior adhesion, allow better coverage, and stain hiding power, it will also protect the underlying metal from rust.

It’s important to choose the right metal primer or undercoat for a project, whether you're looking for something to adhere to a difficult surface, prevent rust from forming, stabilise existing rust or a high-performance system that is going to stand the test of time we have a product suitable. Many of the primers and undercoats available from Coo-Var, International, Jotun, Sherwin-Williams and Rust-Oleum, amongst other manufacturers, have impressive certificates and approvals - including hygiene ratings, fire ratings, Network Rail approval, Highways Agency approval, London Underground approval and more. Ask our Technical Team for help in choosing the right primer or undercoat for your project.

Rawlins Paints stock over 150 metal primers and undercoats, for any scaled project or environment – no matter how extreme the weather conditions are for external application. These range from Rust-Oleum’s CombiPrimer products for smaller surface areas, to Jotun’s Penguard, Pilot and Barrier ranges for larger surface areas in less hospitable environments – such as offshore areas. With many factors determining which primer will be best suit requirements, these may include one or more of the following:

• Heat resistant surface requirements
• Full anti-corrosive or chemically resistant system installation
• Minimum business downtime on a maintenance or extension build
• A new, submerged environment installation
• Surface rust present
• Exposure to high winds, rain, damp/moisture, or sunshine/UV
• Flexibility and extra durability to protect against light vehicular traffic

Each product page will contain at least one datasheet documenting touch-dry times, surface preparation requirements, storage and application cleaning advice, and when the primer can have additional product coatings applied. Incorrectly applied coatings on-top of the primer/undercoat can drastically jeopardise its protective, rust-inhibiting, chemically resistant properties – so always follow application guidelines in the datasheets.

Rawlins Paints’ blog features many articles detailing how rust-inhibiting primers work, full system installations from primers to topcoats, product recommendations for specialist or unusual environments, as well as topics including how to paint on or over stainless steel.

When to Use Metal Primers

Metal primers may not always be required on a project, but will always remain a recommendation to improve surface and substrate protection, as well as extend the lifespan of the topcoat or full system installation.

A metal primer’s primary job is to stop the metal from getting wet, or coming into direct contact with any form of moisture, damp or humidity. Whilst some metals contain anti-corrosive materials (such as the addition of zinc – which oxidises first, before the metal substrate does), without using a primer as an added precaution, over time the paint system will age and may decay or begin to deteriorate. When this happens, oxidation will begin, and can quickly lead to rust forming on the surface. Flaking and peeling paint on a surface is most commonly caused from a primer not being used. Stripping back topcoats from metal that has begun to peel can be a large and expensive task – colours may fade on larger surface areas over time, and simply treating and recoating smaller areas is not a ‘colour matching’ option.

Please note that not all metal primers are rust-inhibiting. Some provide other forms of surface protection and topcoat/system installation preparation. Red oxide primers are rust-inhibitive and should be used on ferrous metals to prevent rust and substrate surface oxidisation.