Spray painting is the best method of painting on larger surfaces and gives even film thickness without any brush marks. check out following video to understand spray painting procedure.
Spray Painting Checklist
- The spray painting equipment used shall be suitable for the intended purpose, shall be capable of properly atomizing the paint to be applied, and shall be equipped with suitable pressure regulators and gauges.
- The air caps, nozzles, and needles shall be those recommended by the manufacturer of the equipment for the material being sprayed.
- The equipment shall be kept in satisfactory condition to permit proper paint application.
- Traps or separators shall be provided to remove oil and condensed water from the air.
- These traps or separators must be of adequate size and must be drained periodically during operations.
- The air from the spray gun impinging against the surface shall show no condensed water or oil.
- Ingredients shall be kept properly mixed in the spray pots or containers during application by continuous mechanical agitation.
- The pressure on the material in the pot and of the air at the gun shall be adjusted for optimum spraying effectiveness.
- The pressure on the material in the pot shall be adjusted when necessary for changes in elevation of the gun above the pot.
- The atomizing air pressure at the gun shall be high enough to properly atomize the paint but not so high as to cause excessive fogging of paint, excessive evaporation of solvent, or less by over spray.
- Spray equipment shall be kept sufficiently clean so that dirt, dried paint, and other foreign materials are not deposited in the paint film.
- Any solvents left in the equipment shall be completely removed before applying paint to the surface being painted.
- Paint shall be applied in a uniform layer, with overlapping at the edge of the spray pattern.
- The spray patterns shall be adjusted so that the paint is deposited uniformly.
- During application, the gun shall be held perpendicular to the surface and at a distance, which will ensure that a wet layer of paint is deposited on the surface.
- The trigger of the gun should be released at the end of each stroke.
- All runs and sags shall be brushed out immediately or the paint shall be removed and the surface repainted.
- Areas inaccessible to the spray gun shall be painted by brush; if not accessible by brush, daubers or sheepskins shall be used.
- All nameplates, manufacturer’s identification tags, finished flange faces, control valve items and similar items shall be masked to prohibit coating deposition.
- If these surfaces are coated, the component shall be cleaned and resorted to its original condition.
- Edges of structural shapes and irregular coated surfaces shall be coated first and an extra pass made later.
- If spray gun shows choking, immediately de-choking procedure shall be followed.