The best paints won’t give value satisfaction if the job isn’t done right. Not doing it right invariably shows, sooner rather than later. But the blame is usually put on the quality of paint. To begin with, therefore, it’s best to watch out for painting defects and know how to solve them & educate the painter.
Defect: BITTINESS:
The painted surface feels rough and coarse. Small particles of solid matter project above the surface of the paint film.
| REASON | SOLUTION |
| · Dust in the atmosphere | · Ensure clean and dust-free surface prior to painting |
| · Dry and broken skin in the paint can | · Strain the paint through cloth before painting |
| · Impurities in the paint can | · Do not apply paint in windy conditions |
| · Unclean paintbrush |
Defect: BLISTERING:
Formation of small bubbles on the surface of the paint film which may eventually burst,
Exposing the surface underneath.
| REASON | SOLUTION |
| · Trapped air or gases | · Allow the surface to dry fully |
| · Moisture beneath the paint film | · Avoid paint application in rain or extreme heat |
| · Corrosion (rust) under the paint film | · Allow each coat, time to dry sufficiently |
Defect: BLOOMING:
Cloudy/dull discoloration and loss of gloss which sometimes forms on the surface of glossy
Paints or lacquers.
| REASON | SOLUTION |
| · Rapid condensation owing to surface cooling | · Avoid painting in extreme humidity |
| · Use of fast evaporating solvents | · Use correct thinner |
Defect: LIFTING:
Gloss reduction and cracking of the finish coat which occurs usually within 48 hours after application.
| REASON | SOLUTION |
| · Solvent used in the paint attacks primer | · Use correct thinner |
| · Paint applied on insufficiently dry primer | · Allow the primer to dry thoroughly |
| · Wrong primer used | · Use correct primer |
| · Wrong thinner in finish paint | · Check gripping between primer and finish coat |
Defect: CRACKING:
Non-uniform breaking-up of the paint film.
| REASON | SOLUTION |
| · If paint is applied on under-dried undercoats. | · Allow sufficient time for coat to dry before applying the next one. |
| · If paint coat is thick. | · To ensure good adhesion, rub the first coat thoroughly with sandpaper. |
Defect: FLAKING & PEELING:
The lifting of the paint film from the surface in the form of scales and flakes.
| REASON | SOLUTION |
| · If previously applied paint films become loose. | · Don’t apply paint on a ill-prepared surface. |
| · Loss of adhesion between paint film and surface. | · Follow correct surface preparation procedure. |
| · Poor flexibility of paint film | · Make sure surface is clean and dry before painting. |
Defect: SAGGING:
The downward movement of the paint film between application and drying resulting in an uneven paint film.
| REASON | SOLUTION |
| · Paint film too thick. | · Avoid thick application. |
| · Wrong thinner. | · Use correct thinner. |
| · Spray pressure too high. | · Maintain correct application pressure. |
Defect: CISSING/PIN-HOLING:
The wet paint film recedes from small areas of the surface leaving them apparently uncoated.
| REASON | SOLUTION |
| · Water, impurities in the pipeline of compressor. | · Ensure surface is free from oil/grease and properly dry. |
| · Keep pipeline of compressor clean and free from water. |
Defect: BRUSH MARKS:
The brush marks are visible.
| REASON | SOLUTION |
| · Over brushing. | · Avoid it. |
| · Application in high viscosity. | · Apply paint of correct viscosity. |
| · Poor quality brush. | · Use the right quality of paint brush |
| · Poor application of paint film. | · Employ correct application technique. |
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