19 types of Paint Failure and their causes
Paint is applied to the surface to serve two purposes, one to decorate and the other to provide protection. Each type of paint has its own life and deterioration earlier to the rated life is considered as paint failure.
On the other hand it looks very simple. Yet even ordinary painting has its own peculiarities.
Causes which are discussed here are ones which end up in premature ageing or failure of paint.
Most of the manufacturers have quality control on the paint. Thus there is only a little possibility that the deterioration of paint is on account of bad Manufacture (Adulteration by workman will not make the original paint bad but it is simply a cheating by workmen).
The featured Image you see above is not an outcome of my perverted imagination but is also an instance of failing of paint.
The failures of a painting job occurs by different causes which may be classified as below:
(1) Poor workmanship in preparing surfaces and applying paint leads to paint failure.
(ii) Lack of adhesion to surface due to moist, humid environment.
(iii) Incorrect type of paint also leads to paint failure as well.
There are many types of Paint failure, but mainly they can be classified as:
1. Blistering of Paint
Basically the paint film is intact but the adhesion between the base and paint film has been destroyed. Blistering of paint surface is due to imprisoned moisture which forces up the paint film into little bubbles or blisters.
Bleeding is the resinous deposits of the sub-surface coming to the paint.
It is the formation of a mist haze or milkiness due to presence of moisture or chilling of surface glossy coat. It would effectually destroy the surface gloss. It is a very common type of paint failure.
Chalking is the powdering of the surface paint due to external exposure and lack of paint binder. It will require washing and rubbing down of chalked surface to provide a sound base for adhesion and sealing and application of new paint.
Crazing is due to hard drying paint being applied on a soft undercoat or One that is not fully dry causing irregular cracking of the surface paint. Remedy is to strip the affected areas and paint.
6. Curtaining and Sagging
This type of paint failure occurs when the paint runs down in drips. This is due to bad workmanship i.e. the uneven application of paint or paint which is too thick which causes it to run.
Flaking is lifting up and peeling away of the paint due to loss of adhesion. It is caused by applying paint over a moist, greasy, chalky or any other insecure surface.
This is due to poor capacity of the paint film which allow paint coat below to show through the finishing coat. It is the result of poor workmanship, incorrect thinning of paint.
This type of paint failure results from chemical changes in the paint which reduces to an unstable jelly like substance. It is due to unsuitable thinners or long storage. It is an uncommon type of paint failure, but care should be taken.
Saponification is a soapy formation of paint due to an attack by alkaline paint. It occurs on fresh (un-matured) cement surface or plaster due to high alkali content on cement.
11. Loss of Gloss
This can be due to porous undercoat or moisture.
This does not require any explanation, it is due to damp conditions. Thus, the major causes of failure of paint can be as follows:
In a newly constructed building the water used during construction process for masonry, etc., takes a long time to evaporate. The water can come from leaky sanitary installation roofs, overflow from tanks, etc. In colder region condensation can be a problem.
14. Salts and Alkalis
These saponify the paints. Damage to porous paint even like dry distemper can be substantial.
15. Unsuitable Surface
Too fresh a surface (in case of cement plaster or concrete) too smooth a surface where paint cannot get a grip, friable contaminated weathered deteriorated surface repainted without taking proper remedial measures are sure causes for paint failure.
16. Unsuitable Conditions for Painting
While painting is done, moisture dirt, dust should not get entrapped in paint film. Very high or low temperature and humidity during application can affect paint. Dust mars gloss and produces a bitty surface. When painting is undertaken, the humidity of the environment should be less than 75%.
17. Wrong Paint
The paint has to be compatible with the base ckoat. It has to be proper according to the environment to which it is exposed. Substandard paints, not properly ground or old paints may be cheap in initial cost but their life is very short. Use of inferior grade paint, such as ready mixed paint on the exterior, is sure to cause trouble.
18. Bad Workmanship and Tools of Painting
Bad workman is in the habit of thinning paint and is a major reason for paint failures. Thinning paint saves him paint as well as labour. A thinned paint film has less life. He
may use bad brushes, rags, etc., for painting thereby the paint film would be non-uniform. Before painting, surface should he checked for soundness.
A useful test for finding out whether the surface is sound or not, it is essential to apply transparent cellophane self adhesive tape to the surface.
If it shows little adhesion when pulled off and brings away loose dust and powder, the surface is unlikely to hold paint film is strong enough, the adhesion may be tested by cutting paint film with 4 sharp blade in a pattern of 2 mm squares, then stick transparent cell-tape and pull it away.
Sound paint should show very little detachment, Old and brittle paint may break up.
19. Painting (interior)
Painting is an important aspect of Interior Design. For building up efficiency, whether in an office, industrial plant or a house, relaxed atmosphere and cleanliness is required. Colours have effect on emotional responses individuals.
Painting walls, ceilings, doors and window is an an and very simple rules if kept in mind can give excellent and durable finish. With the same basic materials of paint and brushes, with negligence a very shady and poor job will result into paint failure.