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Fitz’s Atlas 2™


of coating defects


Coating Defects BLEEDING (also known as ‘Bleed Through’)


Description:


Staining of a paint film by diffusion of a soluble coloured substance from the underlying paint to give undesirable discoloration or staining . Often seen where bituminous or tar based products are overcoated with topcoats in which the tar or bitumen is soluble. Also occurs with emulsion paints.


Probable Causes: ‘Bleed Through’ is generally a full or partial redissolving of the previous coat or an ingredient of a previous coat and can occur when strong solvents are used in the topcoats.


Prevention: Use correct coating specification and materials. Use compatible materials.Use appropriate sealer coat if possible.


Repair:


Remove stained or contaminated layer. Apply a suitable sealer coat which will prevent the diffusion of soluble coloured material from beneath. It may be possible to apply a sealer coat without the removal of the stained/ contaminated layer.


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E SAMPLE


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