Editing Paint (section)

==Failure==
The main reasons for paint failure after application on the surface are the applicator and improper treatment of the surface.

Defects or degradation can be attributed to:
; Dilution
:This usually occurs when the dilution of the paint is not done as per manufacturers recommendation. There can be a case of over dilution and under dilution, as well as dilution with the incorrect diluent.
; Contamination
: Foreign contaminants can cause various film defects.
; Peeling/Blistering
: Most commonly due to improper surface treatment before application and inherent moisture/dampness being present in the substrate. The degree of blistering can be assessed according to ISO 4628 Part 2 or ASTM Method D714 (Standard Test Method for Evaluating Degree of Blistering of Paints). 
; Chalking
: Chalking is the progressive powdering of the paint film on the painted surface. The primary reason for the problem is [[polymer degradation]] of the paint matrix due to exposure of [[UV radiation]] in [[sunshine]] and condensation from dew. The degree of chalking varies as epoxies  react quickly while acrylics and polyurethanes can remain unchanged for long periods.<ref>{{cite book|last= Bayliss |first= D.A. |title= Steelwork corrosion control |year= 2002 |publisher= Spon |location= London |isbn= 978-0-415-26101-2 |pages= 13.6.6 Chalking |edition= 2nd |author2=Deacon, D.H.}}</ref> The degree of chalking can be assessed according to [[International Organization for Standardization|International Standard]] ISO 4628 Part 6 or 7 or [[American Society of Testing and Materials]](ASTM) Method D4214 (Standard Test Methods for Evaluating the Degree of Chalking of Exterior Paint Films).
; Cracking
: Cracking of paint film is due to the unequal expansion or contraction of paint coats. It usually happens when the coats of the paint are not allowed to cure/dry completely before the next coat is applied. The degree of cracking can be assessed according to International Standard ISO 4628 Part 4 or ASTM Method D661 (Standard Test Method for Evaluating Degree of Cracking of Exterior Paints). Cracking can also occur when the paint is applied to a surface that is incompatible or unstable. For instance, clay that hasn't dried completely when painted will cause the paint to crack due to the residual moisture in the clay.
;Erosion
:Erosion is very quick chalking. It occurs due to external agents like air, water etc. It can be evaluated using ASTM Method ASTM D662 (Standard Test Method for Evaluating Degree of Erosion of Exterior Paints). The generation of acid by fungal species can be a significant component of erosion of painted surfaces.<ref>{{cite web|url=http://www.icas.org/ICAS_ARCHIVE/ICAS2006/PAPERS/013.PDF|title=Measures and Test Techniques for Fungus Resistance to Aircraft Materials and Equipment |author1= Xiaohui Wang|author2= Ling Wang|date=2006}}</ref> The fungus&nbsp;''[[Aureobasidium pullulans]]''&nbsp;is known for damaging wall paints.<ref>{{cite web|url=http://www2.hawaii.edu/~johnb/micro/m140/syllabus/week/eucaryotes/fungi/ascomycota.html|title=Ascomycota|author1= John W. Taylor|author2= Joey Spatafora|author3= Mary Berbee|date=1996}}</ref>

<gallery mode="packed" heights="200">
File:Flaking paint on rusting metal.jpg|Peeling

File:Paint chalking.jpg|Polyurethane paint progressively chalking
File:Peeling paint (pink).jpg|Cracking
</gallery>