Are there any defects in the substrate or the paint layer when painting? Good pre-treatment and sufficient visibility or knowledge of the substrate is of great importance when painting. This also applies to the choice of the right preparation or painting products. Why does a paint peel or how do cracks or blisters occur in a paint layer. Why is good cleaning and sanding of the surface so important when painting? Solutions for a number of common problems during and after the processing of paint or paint products.
Paint problems with a wooden surface
When painting, cleaning and careful sanding of the substrate is of great importance to prevent later adhesion problems.
In the table below you will find a number of defects that may occur during, during or after painting. The starting point are the problems that may arise when finishing a wooden surface. This does not alter the fact that these problems and the solutions can also apply to other surfaces in a number of cases.
Flaws in the paint |
Possible causes |
Possible solution |
---|---|---|
Flaking
Local partial or complete loosening of the paint layers |
Paint system applied on a too moist surface
Cracks from the substrate Application of different types of paint on top of each other Low elasticity of the paint used Excessive deformation of the substrate |
Remove old, unsound paint layers with a paint scraper, burner or hair dryer
Apply a new paint system after any pre-treatment |
Powder off
When rubbing the paint layer, it appears to give off, or powder |
Normal aging phenomenon of the paint
The paint is of insufficient quality for outdoor use |
Removal of the powdered surface
Clean, sand and repaint |
Flaking off
Peeling off the top or bottom layers of paint |
Not properly cleaned or degreased
Not sanded enough Too moist surface Apply over weathered wood |
Remove flaky layer
Cleaning and sanding Repaint |
Algae growth
The paint surface is affected by green growth |
Too moist surface
Incorrect, porous paint type Direct contact of the paint system with trees, plants, etc. |
Clean the substrate and remove algae
Treat with algicide Finish with suitable paint |
Cracking
Cracks in the top layer, in combination with peeling |
Too moist surface when applying
Too little elasticity of the paint Apply different types of paint on top of each other Cracks or functioning of the substrate |
Remove old paint layers that are not intact
Clean, sand and rebuild paint system |
Blistering
Local peeling of the paint due to blisters |
Often moisture entrapment in the substrate
Drying of the top layer too quickly Bad surface |
Remove old paint that is not intact
Clean and sand and rebuild paint system |
Bleed
The penetration of constituents / ingredients from the substrate, or from existing paint layers |
Previously applied bituminous products
Carbon black penetration Bleeding woods, such as Merbau |
Application of an appropriate insulation layer
Removing the ‘problem layer’ Cleaning, sanding and applying a new paint system |
Insufficient coverage
Completely or partially insufficient layer thickness |
Poor color coverage, especially red and yellow
Poor quality of the applied paint Insufficient layer thickness on sharp edges and profiles Great contrast between the ground color and the finish |
Apply an extra layer of paint
Choose better quality paint Choice for a different ground color |
Loss of gloss
Loss of gloss of the original paint layer after drying |
Normal aging phenomenon
Insufficient resistance to UV radiation or exposure to the sunny side Quality of the product Environmental influences |
Clean, sand and apply a new layer (s) |
Insufficient adhesion
Paint layer does not adhere sufficiently to the substrate or old paint layer |
Weathered, damp surface
Not properly cleaned surface Damp surface during application Incorrect paint system |
Remove old paint that is not intact
Cleaning, sanding and building a new paint system |
Holy days
Place (s) where no paint has been applied |
Places that were skipped during painting | Paint skipped places, but it is better:
Repaint completely |
Craters
(Circular) spots in the substrate, due to contamination with wax, grease, silicones and the like |
Silicone or (polish / furniture) wax contamination
Insufficient cleaning of the substrate |
Clean the substrate with a suitable cleaning agent
For silicones, add an anti-silicone preparation to the paint Apply a new top coat |
Layer thickness (partially) insufficient
Too thin paint layer (s) applied |
Substrate too porous or too coarse
Incorrect construction of the paint system Incorrect method of application Insufficient edge coverage Use of poor quality paint |
Apply extra layer thickness (s)
Paint over with good quality paint |
Work up
Wrinkling of the surface, immediately after applying a paint product |
The new paint layer contains aggressive ingredients, which the old layer soaks up | Remove old layers of paint
Choosing a different type of paint (almost always depends on the solvent of the paint) |
Fungi
Occurs on a damp surface |
Frequent condensation
Bad sealing / watering Bad ventilation |
Solve moisture / watering problem.
Remove old paint Repair if necessary Apply a suitable new coat of paint |
Scorching
With an alkyd resin paint: by applying a paint layer that is too thick, when the surface dries too quickly |
Too thick coat of paint applied in one go
Underlying paint layer insufficiently dried |
Remove scorched paint layers
Apply new paint layer (s) |
Yellowing
Discolouration, usually due to insufficient daylight (cupboards, cellars, etc.) In light colors, first visible by adding moderate pigments |
Unavoidable with alkyd resin paint | Deliberately opt for a slightly aged shade
Apply a less yellowing acrylic paint |
Weathering of wood
Aging of the wood due to weathering and environmental influences |
No or insufficient protection
Porous finishing layer |
Delete any old layers
Remove weathered wood cells as much as possible Treat with design water Build a new paint system |
Saponification
Due to attack by alkalis. Paint has blisters and peeling |
Incorrect paint system for the substrate
Moisture leakage |
Solve moisture leakage
Remove old paint layers Apply alkali-resistant paint |
Flow
Poor flow, leaving many visible brush marks, or orange peel skin (foam roller) |
Too fast drying (open time of the paint)
Incorrect diluent Incorrect application material (brush or roller) Normal product feature |
Sanding the substrate tightly
Apply new suitable finishing coat |
Dirt adhesion
Dirt adhesion on the paint surface |
Structured surface
Textured paint applied Use porous paint |
Cleaning and sanding the surface
Applying good quality paint layer (s) |
Sinking of the paint layer
Stain formation due to irregular absorption of the substrate |
Porous surface
Sanded spots Putty spots |
Apply extra layer (s) |
White translucent
Due to moisture ingress / entrapment under a transparent lacquer or stain |
Too few coats applied
Application of a product that is too porous Moisture from the substrate |
Delete old layers
Treat weathered wood with design water Apply new system |
Soft coat of paint
Paint remains soft and soft and does not dry through |
Paint applied during unworkable weather
Incorrect mixing ratio when using two-component products |
Remove layers of paint
Sanding and cleaning Apply new paint layer (s) |
Sags or drippers
Local sags, drippers or tears |
Inadequate distribution or streaking of the paint
Too much paint applied locally |
After drying, sand or put away the sags
Level / fill if necessary Treat putty areas with primer Apply new paint layer (s) |