Understanding Orange Peel in the Bathtub, Tile, and Countertop Refinishing Industry

Orange peel is a prevalent texture issue in the painting process, particularly when using turbine HVLP (High Volume Low Pressure) spray equipment for refinishing. This effect resembles the bumpy surface of an orange peel and can detract from the desired smooth, glossy finish.

Causes of Orange Peel

1. Spray Technique: Inconsistent or improper spraying techniques, such as incorrect spray gun distance, speed, and angle, can lead to orange peel.
2. Viscosity of Coating: Incorrect coating viscosity can contribute to texture issues. The coating material must be properly adjusted according to the manufacturer's recommendations and environmental conditions.
3. Temperature and Humidity: Environmental factors significantly affect the drying and curing process. High temperatures or low humidity levels can cause the coating to dry too quickly, resulting in orange peel.
4. Spray Equipment Setup: Inadequate setup of spray equipment, including incorrect air pressure, nozzle size, or fluid flow, can also result in orange peel.

However, it’s crucial to understand that the majority of orange peel issues do not arise from under-thinned or under-reduced topcoats or primers. Instead, the primary cause is the use of underpowered turbine HVLP sprayers. Many refinishers still use 2-3 and even 4-stage turbines that were adequate 20 years ago when paints had 45% solids. Today, with VOC compliance being mandatory in most areas, a more powerful 5 or 6-stage turbine is necessary to properly atomize high solid coatings.

Consequences of Over-Reducing High VOC Coatings

Over-reducing high VOC coatings is not a viable solution, as it can break down the chemical integrity of the coating. This leads to several issues:

• Uneven Drying: The coating may not dry uniformly, causing texture inconsistencies.
• Down-Glossing or Loss of Gloss: The finish can lose its intended sheen.
• Pinholes: Tiny holes can form in the coating, compromising its appearance and durability.
• Blushing: A milky appearance can develop due to trapped moisture.
• Reactivation of Existing Coatings: Excessive reducer can reactivate the underlying coating, causing it to bubble and fail.

Preventing Orange Peel

1. Proper Spray Technique: Train technicians to maintain a consistent distance, use even strokes, and slightly overlap each pass.
2. Adjust Coating Viscosity: Ensure the coating material is mixed and thinned correctly. Follow manufacturer guidelines for mixing ratios and thinning agents.
3. Control Environmental Conditions: Maintain stable temperature and humidity levels in the spraying area to promote proper drying and curing.
4. Regular Maintenance of Spray Equipment: Keep equipment clean and well-maintained. Check and adjust air pressure, nozzle settings, and fluid flow as needed.
5. Use Adequate Equipment: Invest in modern, powerful 5 or 6-stage turbines to meet the demands of high solid coatings and VOC compliance.

Repairing Orange Peel

If orange peel occurs, it can be repaired by:

1. Sanding the Surface: Use fine-grit sandpaper (e.g., 800-1000 grit) to smooth the texture.
2. Applying Additional Coats: Follow proper spraying techniques to apply additional coats and achieve a smooth finish.
3. Using Leveling Agents: Some coatings benefit from additives that improve flow and leveling properties.
4. Buffing and Polishing: After curing, buff and polish the surface to restore gloss and achieve a uniform finish.

By focusing on proper technique, equipment, and environmental control, refinishers can minimize orange peel and achieve high-quality, glossy coatings. Continuous training and maintenance are essential for consistent, professional results in the bathtub, tile, and countertop refinishing industry.

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