Getting to Know Surface Preparation by Sandblasting

Surface treatment is a general application of sandblasting. Surface preparation is very critical before coating the surface. Make proper preparations before starting painting. Otherwise, the coating may fail prematurely. Therefore, the degree of surface preparation by sandblasting may affect the performance and service life of the coating. It will reduce the adhesion between the coating and the object and cause physical damage, even if exist small number of surface pollutants, such as grease, oil, and oxide. It is invisible to chemical pollutants such as chloride and sulfate, which absorb water through the coating, resulting in the coating in early failure. Thus, correct surface finishing is very essential.

What is surface preparation?

Surface preparation is the first stage of treatment of metal or other surfaces before any coating is applied. It involves cleaning the surface of any contaminants, such as oil, grease, loose rust, and other mill scales, and then creating a suitable profile to which paint or other functional coatings will be bonded. In coating application, it is very important to ensure the durability of coating adhesion and effective corrosion prevention.

What is sandblasting?

The sandblasting process mainly involves air compressors, abrasives, and nozzles. The high-pressure airflow pushes abrasive particles onto the object surface through the pipe to produce a roughness profile that facilitates the adhesion between the coating and the surface.

Nozzle Recommendation

The nozzles you can apply are as below:

Venturi Nozzle: Venturi nozzles feature a wide blast pattern that promotes blasting more effectively. It contains three sections. It starts with a long tapered converging inlet, followed by a short flat straight section, and then has a long diverging end which becomes wider when reaching up close to the outlet of the nozzle. The Principle is that a reduction in pressure of fluid leads to an increase in the fluid’s velocity. Such a design helps to increase work efficiency by two-thirds.

Straight Bore Nozzle: It includes two parts containing the converging inlet and full-length straight bore part. When compressed air enters the converging inlet, the media flow of sodium bicarbonate particles speeds up for the pressure difference. The particles exit the nozzle in a tight stream and produce a concentrated blast pattern upon impact. This kind of nozzle is recommended for blasting small areas.

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