Coating Solutions

image

Common Coating Solutions for all Types of Applications & Surfaces. Click on the pictures below that most represent your coating problem. A solution is outlined for each.

image
Saponification

Symptoms

The coating is not resistamt to alkali. Blisters appear, paint softens and flakes off.

Cause

Incorrect use of product Application of alkyd based topcoat to alkaline material (e.g. concrete or cement) Humidity problems Caustic stripped surface not neutralised SolutionRemove all paint layers and apply a new alkali resistent system. Prevent water penetration. Apply an alkali resistent system.

image
Soft Paint Film

Symptoms

The dry film has a soft and weak character.

Cause

Paint applied too thickly Painted during impossible working conditions With two-component products the wrong mixing ratio is used SolutionPaint layers that are not sound should be completely removed. Apply a suitable protection system and allow a longer drying time to improve the conditions under which it is painted.

image
Holidays (Missed Areas)

Symptoms

Bare spots.

Cause

Contamination (see 'Cissing' or 'Fish eyes') Areas have not been touched during the painting process.

Solution

Coat non-touched spots with the used product and primer/base stain if required. If necessary, apply an additional layer.

 
image
Peeling of Coating

Symptoms

Total/local loss of adhesion of paint system.

Cause

Internal tension in paint films Deformation of substrate Humidity or gas formation Wrong paint sytem Several layers are applied which are not compatible with each other Insufficient flexibility of applied paint Cracking originating from substrate Paint system applied to damp substrate or one with a high moisture content. SolutionPaint layers that are not sound should be removed. After the appropriate pretreatment, a new system should be applied. Touch up bare spots with primer/undercoat and finish with topcoatu

image
Floating / Flooding

Symptoms

Multi coloured effect.

Cause

One of the pigments used floats to the surface causing a multi colored effect (happens mostly with blue, green and violet pigments) SolutionSand after drying. Apply a further top coat which doesn't 'float'.

image
Salt Efflorescence

Symptoms

A white salt deposit appears, usually on plywood or brickwork.

Cause

Occurs with some plywoods Excess salts migrate to surface through coating SolutionClean down. May re-occur. Apply freshen up coats if necessary.

image
Insufficient Adhesion

Symptoms

The coating adheres insufficiently to the substrate or previous coats.

Cause

Unsuitable primer applied Wrong product Damp substrate during painting Contaminated substrate (not cleaned or degreased) Weathered timber not removed before coating Previous Coating Unstable SolutionCoating layers that are not sound should be removed. Substrate problem should be addressed (cleaning, degreasing, sanding etc.). Apply a new, suitable coating system.

image
Insufficient Flexibility

Symptoms

A crackle effect or cracking appears.

Cause

Different paint systems intermixed Too brittle paint system caused by ageing Applied product cannot follow the movements of the substrate and/or underlying paint layers SolutionRemove all coating and apply a new, suitable coating system.

image
Haziness (Blooming)

Symptoms

At the surface a greyish haze appears which gives the paint a dull glow.

Cause

Fog and/or humidity during drying Insufficient ventilation Coating over-thinned SolutionSand and apply a new top coat.

image
Yellowing

Symptoms

The applied pale colour turns yellow.

Cause

With an alkyd based topcoat this is intrinsic to the binder.SolutionSand and clean. Often solved by altering the chosen colour to a greyish option, which makes the problem less visible. Apply waterbased paints, which are less prone to yellowing.

image
Lifting

Symptoms

A wrinkling effect immediately after painting.

Cause

The applied coat contains aggressive components which will dissolve the undercoat Softening, swelling or separation from the substrate of a dry coat as the result of the application of a subsequent coat SolutionApply another type of paint as topcoat or remove old paint layers and apply a new paint system. Use compatible paint products.

image
Algae Growth

Symptoms

The coating surface shows a green growth, usually on north facing timbers.

Cause

Plants, bushes and trees in close proximity to coating system. High humidity of surroundings and/or moisture content of substrate SolutionRemove / kill algae/mould and clean substrate. Treat with a fungicidal (or diluted bleach) solution. Scrub dead spores loose, rinse clean and allow to dry fully. Where necessary, redecorate with suitable coating.

image
Sagging

Symptoms

Localised "drips" and "tears" appear.

Cause

Paint not applied evenly over the surface Coats applied too heavily Paint doesn't have the right consistency (incorrect thinning) SolutionRemove by sanding after thorough drying is completed. Apply the coatings thoroughly and and evenly. Apply at the proper viscosity and the recommended wet film thickness.

image
Blistering

Symptoms

Large or small blisters, possibly only in topcoats of the system.Generally only local loss of adhesion of paint system.

Cause

Application over localised contamination (e.g. grease, oil, resin) Humidity or gas vapour formation from the substrate Solvent could be trapped between coats of the paint system if the primer or mid coat has not been allowed to dry fully. Incorrect coating system, e.g. quick drying top coat, at which the contained organic solvent causes blisters. SolutionCoating layers that are not sound should be removed. After the right pre-treatment against moisture penetration, a new system should be applied. Touch up bare spots with primer and finish with finish topcoat.

image
Bleeding

Symptoms

The bleeding through of contents of the substrate through existing paint layers or systems.

Cause

Certain timbers such as Western Red Cedar, Oak, Meranti or Idigbo are prone to bleeding Chemicals within timbers prone to bleeding (i.e. timbers with a high natural extractive content) are mobilised by water Colors from previous coatings such as bitumen or creosote can bleed through Problem more prevalent with water-borne coatings. SolutionClean the coating surface to make sure that the bleeding components have been removed and apply a fresh coating system. Apply sufficient layer thickness to prevent water from dissolving the bleeding wood content. Apply a full primer. Finish with one or two coats of finish.

image
Dirt Collection

Symptoms

Dirt on surface of coating.

Cause

Textured (not smooth) coating and/or surface Thermoplastic paint type Exposure in industrial/urban area SolutionClean surface thoroughly. Treat with a non-porous, less dirt collecting coating system.

image
Fungal Growth

Symptoms

Fungal growth can appear with high humidity of surroundings or damp substrate or high moisture content.

Cause

Condensation on surface Water ingress Poor ventilation SolutionsTake measures that ensure the substrate will dry (and remain dry). Clean old coating layers with a suitable fungicidal wash/bleach solution and apply a suitable top coat.

image
Insufficient Film Thickness

Symptoms

Applied coating thickness is too low.

Cause

Wrong coating system Porous substrate Heavily textured substrate Sharp edges/arrises Influences of application method (brushed too thinly, rolled) SolutionComplete finish with a suitable system, If necessary, apply an additional layer.

image

Flaking

Symptoms

Loss of adhesion of coating system on substrate or loss of intercoat adhesion.

Cause

Insufficient cleaning / degreasing Unsuitable system Insufficiently sanded Damp substrate or high moisture content Condensation on substrate at application Solution Coating layers that are not sound shall be removed. After the correct pretreatment, a new system should be applied. Apply suitable primer/base stain and top coat(s).

image
Crackle Formation

Symptoms

A crackle effect appears, random cracks all over the surface

Cause

Coating system too brittle for the substrate Layers applied too thickly Coatings applied at too low temperature and/or too high relative humidity Applied product cannot follow the movements of the substrate Contamination between layers SolutionCoating layers that are not sound should be removed. After the right pre-treatment, a new system should be applied.

image
Cracking

Symptoms

The coating system shows localised cracking, which results in loss of adhesion and flaking.

Cause

Internal stresses of coating system Deformation or breakdown of the substrate e.g. joints opening, splits in the timber Unsuitable coating system Several layers are applied which are not compatible Insufficient flexibility of applied paint Cracking originating from substrate Moisture on substrate at application SolutionCoating layers that are not sound should be removed. After the right pretreatment, a new system should be applied. Touch up bare spots with primer and finish.

image
Blushing

Symptoms

When humidity is trapped in woodstains or varnishes, white spots/patches may appear.

Cause

Damp substrate or humid atmosphere when coating was applied or during drying Porous varnish/stain type Water getting in (moisture ingress) Insufficient coats applied, or coats applied too thinly SolutionRemove old varnish/stain layers; if necessary treat with wood bleach, which will restore the original wood color. Consequently treat with a new system.

image
Brushmarks

Brush marks, orange peel poor levelling etc.

Cause

The open time of the product is too short Incorrect dilution Unsuitable brush or roller Application conditions too hot or too cold SolutionSand thoroughly and apply a further coat to a better standard. Use a good quality brush (synthetic for water-borne coatings

image
Insufficient Hiding

Symptoms

Insufficient obliteration of the substrate colour by opaque top coats.

Cause

Contrast between primer and finishing coat is too large Too low coating layer thickness, e.g. on sharp edges and profiles - or too few coats Characteristic of the color (eg bright colours) SolutionClean and sand substrate. Round off sharp edges. Primt/undercoat with a suitable shade when using poor hiding colors. Completely refinish with top coats.

image
Craters

Symptoms

Contamination of the substrate (e.g. silicone, grease, wax)

causes

surface defects . This results in areas where the coating does not form a complete film over the substrate.CauseOften a silicone or wax contamination Surface not cleaned sufficiently before application When spray-applied: poor film formation Open pored timber SolutionClean surface with a suitable emulsion cleaner or silicone remover where appropriate. It may be necessary to remove affected coatings. Primer or base stain should be worked/brushed well into open pored timbers

image
Loss of Gloss

Symptoms

Decrease of gloss level.

Cause

Normal ageing effect Product has insufficient resistance against UV radiation Product characteristics Environmental influences SolutionClean and sand substrate. Finish.

image
Chalking

Symptoms

The paint system shows a powdery surface.

Cause

Normal ageing effect Insufficient outdoor durability of product Product property (high extender content/pigment content/based on epoxy resin) SolutionRemove powder at the surface. Clean and sand substrate. Touch up bare spots. Finish with one or two coats.