Proper surface preparation is essential before applying any specialist industrial coating to plant machinery and equipment. 

Whether you’re refurbishing a digger, loader, dumper, or piling rig, a high-performance coating system will only perform at its best if the substrate is clean, sound, and ready to receive it.

Preparation not only improves adhesion but also extends the life of the coating, reduces future maintenance requirements, and ensures your equipment stays in good working order for longer.

Here’s a step-by-step guide to preparing plant machinery for painting, based on best practice and experience in tough, real-world conditions.

 

1. Start with thorough cleaning

Why it matters:
Plant machinery operates in harsh environments – construction sites, quarries, roadsides – where it collects mud, cement, oil, grease and grime. All of these must be removed to give the coating a proper foundation.

Steps to take:

• Use a pressure washer or steam cleaner to remove heavy soiling and debris from surfaces.
• Pay close attention to joints, pivots, hydraulic arms, engine covers and undercarriage areas.
• Allow the machine to fully dry before moving on to degreasing.

2. Degrease all surfaces

Why it matters:
Oils and hydraulic fluids left on the surface can compromise adhesion and cause blistering or peeling after painting.

Steps to take:

• Apply a quality degreasing solution using a clean cloth or spray bottle.
• Allow it to soak for a few minutes to break down any residue.
• Wipe thoroughly using lint-free paper towels or cloths, changing them frequently.
• Do not allow the degreaser to evaporate naturally, as this can leave contaminants behind.

3. Abrade or blast to remove rust and create a profile

Why it matters:
Old coatings, corrosion, and smooth finishes must be mechanically abraded or blasted away to provide a suitable “key” for the new paint to adhere to.

Options include:

• Manual sanding or machine grinding (ideal for spot repairs and smaller machines)
• Wire brushing for removing loose rust
• Shot blasting or grit blasting for full refurbishments or heavy corrosion

Surface profile:
For best results, aim for a surface profile of 25–50 microns – enough to allow primer to grip effectively, especially on structural or load-bearing steel.

 

4. Inspect existing coatings and primers

Why it matters:
If the equipment already has a factory or previously applied primer or topcoat, it must be checked for soundness. Coating over failing paint will simply lead to new problems.

Steps to take:

• Check for flaking, bubbling, or rust bleed-through.
• If the existing coating is well-bonded and in good condition, it can be sanded and overcoated.
• If adhesion is poor or rust is present beneath the surface, remove the coating completely and start from bare metal.

5. Final dust removal and tack rag wipe

Why it matters:
Residual dust from sanding or blasting can interfere with paint application and finish.

Steps to take:

• Use compressed air, vacuum tools, or clean, dry cloths to remove all traces of dust.
• As a final step, lightly wipe over the surface with a tack rag or cloth lightly dampened with degreaser to remove any remaining particles.

Additional tips for plant machinery preparation

 

• Work in a clean, dry, well-ventilated area: If possible, move equipment indoors during surface preparation and coating.

• Mask sensitive components: Cover rubber seals, hydraulic rams, glass, and electrical components to prevent accidental coating.

• Choose the right primer and topcoat: Once the surface is ready, select a compatible system designed for heavy-duty use on plant machinery, such as epoxy primers followed by polyurethane topcoats.

Proper preparation is the single most important factor in achieving a long-lasting, hard-wearing coating on plant machinery. 

Skipping steps or rushing the job can result in coating failure, equipment degradation, and costly rework. By following a clear and consistent preparation process, you ensure your coating system performs to its full potential, keeping your plant assets protected, presentable, and ready for the next job.

For advice on choosing the right preparation products or coating systems, contact our technical team today.

 

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Pronto Paints have been working to protect plant machinery for over 35 years and have an exhaustively researched range of dedicated coatings. Click here to check out our technical specifications. 

Want to book a callback or arrange a coating trial with one of our in-house experts? Drop an email to info@prontopaints.com

 

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