Primer

Using the correct automotive primer is a critical step in any paint repair or restoration project. Whether you are touching up a stone chip, refinishing a replacement panel, or completing structural welding repairs, primer creates the foundation for long-lasting paint performance. Repco’s range of primer paint products includes etch primer, epoxy primer, acrylic primer, high build primer, primer filler, primer sealer, plastic primer, aluminium primer, and weld through primer to suit a wide range of automotive applications.

Primer does more than prepare a surface for colour. A quality car primer seals bare substrates, promotes adhesion, reduces moisture penetration, and helps prevent corrosion forming beneath the topcoat. Repco’s range of automotive primer products is designed for compatibility with common automotive paint systems, making it easier for you to achieve reliable and consistent results.

Why is it important to use primer when painting?

Applying colour directly to bare metal, filler, or plastic can lead to poor adhesion, uneven gloss levels, and early paint failure. Automotive primer forms a bonding layer that anchors subsequent coats. Repco’s range of primer spray paint and spray primer options allows you to apply a controlled, even layer whether you are completing a small repair or refinishing an entire panel.

For bare steel, acid etch primer, also known as etching primer, chemically bonds to the surface while helping to inhibit corrosion. This type of metal primer is particularly useful after sanding back to clean steel during rust repairs. Aluminium primer is formulated to adhere to non-ferrous metals, preventing oxidation beneath the paint film.

Epoxy primer provides strong corrosion resistance and excellent sealing properties. It is commonly used on chassis rails, suspension components, engine bays, and restoration projects where long-term protection is required. Repco’s range of epoxy primer and 2k primer systems supports more demanding applications where chemical resistance and durability are priorities.

High build primer, hi fill primer, or high fill primer is designed to level minor surface imperfections. After body filler work, applying spray putty, filler primer, or primer filler helps fill sanding marks and low spots. Once cured, the surface can be sanded smooth to create a flat base for colour. Repco’s range of high build primer and spray putty products makes it easier to achieve a professional finish in a home workshop or trade environment.

What is weld through primer?

Weld through primer is a specialised coating applied to metal surfaces before welding. It contains conductive particles, typically zinc-based, that allow current to pass through during welding while leaving behind corrosion-resistant material between overlapped panels.

In automotive repair, weld through primer is used when replacing panels such as floor sections, sills, quarter panels, and chassis components. These areas often involve spot welds or plug welds that join two panels together. Once welded, the internal mating surfaces are no longer accessible, making corrosion protection essential prior to assembly.

Repco’s range of weld through primer products is designed for structural automotive work. After welding, you can apply epoxy primer or metal primer over the exposed area, followed by car seam sealer to close gaps and prevent moisture entry. Using Repco’s range of automotive primer products in combination ensures both visible and hidden surfaces receive appropriate protection.

What is seam sealer?

Seam sealer is a flexible compound used to seal joints between panels. Factory-built vehicles rely on seam sealing to prevent water, dust, and road contaminants entering through spot-welded joins. During repair work, replicating this protection is essential.

Car seam sealer is generally applied over primed metal and before the final colour coat. It remains flexible after curing, allowing panels to flex slightly without cracking the seal. Common areas for application include wheel arches, floor pan joins, firewall seams, boot floors, and around replacement panels.

Repco’s range of seam sealer and primer sealer products is formulated for automotive use and compatible with common paint systems. Applying seam sealer over a properly prepared and primed surface ensures long-term resistance to moisture and corrosion in high-risk areas.

What preparation should I do before using primer?

Surface preparation determines the success of your paint system. Begin by removing rust, loose paint, and contaminants. Sand the surface to create a mechanical key. The grit selection will depend on whether you are stripping to bare metal or scuffing existing paint.

Thoroughly degrease using an appropriate wax and grease remover. The surface must be clean, dry, and free of dust before applying any paint primer. Mask adjacent panels carefully to prevent overspray.

If you have exposed bare steel, apply acid etch primer or etching primer from Repco’s range of automotive primer products. For aluminium panels, select a dedicated aluminium primer. Where plastic bumpers or trims are involved, use a plastic adhesion promoter before applying plastic primer or plastic paint primer. A plastic adhesion promoter improves bonding on flexible substrates and reduces the risk of peeling.

Repco’s range of primer spray, primer spray paint, and spray primer products allows you to choose aerosol or spray gun formats depending on the scale of your repair. Matching the correct primer for plastic, metal, or previously painted surfaces helps ensure compatibility and durability.

What types of primer would I use on my vehicle?

Different substrates and repair types require different primers. Etch primer or acid etch primer is best suited for bare steel. Epoxy primer is ideal for corrosion resistance and sealing, especially in restoration or underbody work. Acrylic primer is commonly used for general refinishing tasks.

High build primer, hi fill primer, or primer filler is applied over body filler repairs to level imperfections. Filler primer and spray putty products are typically sanded smooth before topcoat. Primer sealer can be used as a final uniform layer to isolate repairs and provide a consistent base colour.

Plastic primer and primer for plastic are essential for bumpers, mirror housings, and interior trims. A plastic paint primer combined with a plastic adhesion promoter improves durability on flexible parts. Aluminium primer is required for alloy panels to prevent corrosion beneath the coating.

Repco’s range of primer paint, automotive primer, epoxy primer, acrylic primer, high fill primer, weld through primer, primer sealer, and seam sealer products provides a comprehensive system for automotive refinishing. By selecting from Repco’s range of primer spray paint and specialised car primer options, you can prepare, protect, and finish your vehicle panels with confidence and consistency.

To support your refinishing work, consider complementary categories such as automotive body fillers and repair compounds, sanding abrasives and masking products, and colour-matched automotive topcoat spray paints available through Repco’s range.