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Coating Faults: Common Issues and Solutions

Coating Defects and Causes

Coating Faults: Common Issues and Solutions

Coating faults can be frustrating for both professionals and DIY enthusiasts. In this blog post, we will define some common coating faults as defined in BS 2015, Glossary of Paint and Related Terms, and discuss potential causes and solutions for each issue.

Bittiness

Bittiness is the presence of small, hard particles in a coating that give it an uneven, rough texture. This fault can be caused by contamination of the coating material, improper mixing or application of the coating, or the use of low-quality raw materials. To fix bittiness, the root cause of the issue should be identified and addressed, and the affected area may need to be sanded down and re-coated.

Bleeding

Bleeding is the migration of a substance (such as tannins or dyes) from the substrate into the coating, causing discoloration or staining of the coating. This fault can be caused by insufficient drying or curing of the substrate before applying the coating, or by using a coating that is not compatible with the substrate. To fix bleeding, the affected area should be sanded down and re-coated with a compatible coating. It may also be necessary to address the underlying cause of the bleeding, such as properly drying the substrate or using a different type of coating.

Blistering

Blistering is the formation of bubbles or blisters on the surface of a coating. This fault can be caused by improper surface preparation, the use of a coating that is not compatible with the substrate, or the presence of moisture or heat during the drying process. To fix blistering, the affected area should be sanded down and re-coated after properly preparing the surface and ensuring that the right type of coating is used. It may also be necessary to address the underlying cause of the blistering, such as properly drying the substrate or using a different type of coating.

Bloom

Bloom is the formation of a powdery or chalky residue on the surface of a coating. This fault can be caused by the use of a low-quality coating or improper curing of the coating. To fix bloom, the affected area should be cleaned and re-coated with a higher-quality coating and allowed to properly cure. It may also be necessary to address the underlying cause of the bloom, such as using a different type of coating or ensuring that the coating is properly cured.

Chalking

Chalking is the formation of a powdery or chalky residue on the surface of a coating due to weathering or UV exposure. This fault can be caused by the use of a low-quality coating or improper curing of the coating. To fix chalking, the affected area should be cleaned and re-coated with a higher-quality coating and allowed to properly cure. It may also be necessary to address the underlying cause of the chalking, such as using a different type of coating or ensuring that the coating is properly cured.

Cissing

Cissing is the formation of small, circular craters in a coating. This fault can be caused by the presence of moisture or other contaminants in the coating material, improper mixing or application of the coating, or the use of low-quality raw materials. To fix cissing, the root cause of the issue should be identified and addressed, and the affected area may need to be sanded down and re-coated.

Cracking

Cracking is the formation of deep, visible cracks in a coating. This fault can be caused by improper surface preparation, the use of a coating that is not compatible with the substrate, or the presence of moisture or heat during the drying process. To fix cracking, the affected area should be sanded down and re-coated after properly preparing the surface and ensuring that the right type of coating is used. It may also be necessary to address the underlying cause of the cracking, such as properly drying the substrate or using a different type of coating.

Cratering

Cratering is the formation of small, circular craters in a coating. This fault can be caused by the presence of moisture or other contaminants in the coating material, improper mixing or application of the coating, or the use of low-quality raw materials. To fix cratering, the root cause of the issue should be identified and addressed, and the affected area may need to be sanded down and re-coated.

Curtaining/sagging

Curtaining or sagging is the formation of visible folds or wrinkles in a coating due to improper application or drying. This fault can be caused by applying the coating too thickly, applying the coating in humid or cool conditions, or not allowing the coating to properly dry before applying a second coat. To fix curtaining/sagging, the affected area should be sanded down and re-coated after ensuring that the coating is applied correctly and given adequate time to dry.

Flaking

Flaking is the detachment of small pieces of a coating from the substrate. This fault can be caused by improper surface preparation, the use of a coating that is not compatible with the substrate

Flocculation

Flocculation is the separation of a coating into distinct layers or clumps. This fault can be caused by improper mixing or storage of the coating, the presence of contaminants in the coating material, or the use of low-quality raw materials. To fix flocculation, the root cause of the issue should be identified and addressed, and the affected area may need to be sanded down and re-coated. It may also be necessary to properly mix and store the coating to prevent future flocculation.

Holidays

Holidays, also known as pinholes or voids, are small areas of a coating that have not adhered to the substrate. This fault can be caused by improper surface preparation, the use of a coating that is not compatible with the substrate, or the presence of contaminants on the surface. To fix holidays, the affected area should be sanded down and re-coated after properly preparing the surface and ensuring that the right type of coating is used. It may also be necessary to address the underlying cause of the holidays, such as properly cleaning the surface or using a different type of coating.

Lifting

Lifting is the separation of a coating from the substrate due to the presence of moisture or other contaminants. This fault can be caused by improper surface preparation, the use of a coating that is not compatible with the substrate, or the presence of moisture or other contaminants during the application process. To fix lifting, the affected area should be sanded down and re-coated after properly preparing the surface and ensuring that the right type of coating is used. It may also be necessary to address the underlying cause of the lifting, such as properly drying the substrate or using a different type of coating.

Orange-peel

Orange-peel is the formation of a rough, uneven texture on the surface of a coating resembling the skin of an orange. This fault can be caused by improper application of the coating, the use of a coating that is not compatible with the substrate, or the presence of contaminants on the surface. To fix orange-peel, the affected area should be sanded down and re-coated after ensuring that the coating is applied correctly and the right type of coating is used. It may also be necessary to address the underlying cause of the orange-peel, such as properly cleaning the surface or using a different type of coating.

Pin holing

Pin holing, also known as holidays, is the presence of small areas of a coating that have not adhered to the substrate. This fault can be caused by improper surface preparation, the use of a coating that is not compatible with the substrate, or the presence of contaminants on the surface. To fix pin holing, the affected area should be sanded down and re-coated after properly preparing the surface and ensuring that the right type of coating is used. It may also be necessary to address the underlying cause of the pin holing, such as properly cleaning the surface or using a different type of coating.

Residual Tack

Residual tack is the presence of a sticky or tacky residue on the surface of a coating. This fault can be caused by improper curing of the coating, the use of a coating that is not compatible with the substrate.

Ropiness

Ropiness is the formation of long, thin strands or ropes in a coating due to improper mixing or application. This fault can be caused by the presence of contaminants in the coating material, improper mixing or application of the coating, or the use of low-quality raw materials. To fix ropiness, the root cause of the issue should be identified and addressed, and the affected area may need to be sanded down and re-coated. It may also be necessary to properly mix and apply the coating to prevent future ropiness.

Saponification

Saponification is the chemical reaction between a coating and a substrate, resulting in the formation of soap-like scum on the surface. This fault can be caused by the use of a coating that is not compatible with the substrate, or the presence of moisture or other contaminants on the surface. To fix saponification, the affected area should be sanded down and re-coated with a compatible coating. It may also be necessary to address the underlying cause of the saponification, such as properly cleaning the surface or using a different type of coating.

Wrinkling/rivelling

Wrinkling or rivelling is the formation of visible folds or wrinkles in a coating due to improper application or drying. This fault can be caused by applying the coating too thickly, applying the coating in humid or cool conditions, or not allowing the coating to properly dry before applying a second coat. To fix wrinkling/rivelling, the affected area should be sanded down and re-coated after ensuring that the coating is applied correctly and given adequate time to dry.

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