Surface Preparation

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Grit blasting, often referred to as sand blasting, shot blasting or abrasive blasting, is the cleaning of a surface by projecting abrasive media at the substrate at high velocity. Grit blasting is an extremely effective method of surface preparation for removing rust, old paint and scale. Selecting the grit is key to ensuring the correct surface profile and standard of cleanliness is achieved to meet the project specification.

Wet blasting, often referred to as wet abrasive blasting and similar to slurry blasting, is a method of dustless grit blasting where clean water is injected at the blast nozzle to dampen the grit and help contain the dust. The level of surface cleanliness is a different classification to that achieved by dry grit blasting, but where the coating system and site allows this method of surface preparation can be an extremely effective means of containing the dust and preventing local contamination.

Captive blasting, also referred to as captive shot blasting, captive abrasive blast cleaning and blastracking, is where a steel or concrete surface is prepared using captive blasting machines that recycle the shot. A mix of steel shot and angular grit is usually used to achieve the specified surface profile. Over enough square meterage, these machines can become very cost effective by reducing shot used and cleaning time, whilst still achieving the same standard of cleanliness as traditional gri

A method of tool preparation used to achieve a comparable standard of surface cleanliness as grit blasting or shot blasting. During bristle blasting, bristles on a rotary bristle head are propelled from a bar against the substrate which mimics the treatment of grit blasting. A surface profile can be achieved and it is completely dustless and more cost effective over smaller areas.

The pressure of the water jet will determine the standard of surface cleanliness achieved and is determined by the specification. Low pressures can clean the surface from dirt, contaminants and soluble salts which can cause premature defects of the coating system if left unaddressed. Higher pressures can remove unsound coatings and even all coatings back to bare steel. The benefit of water jetting over grit blasting is no abrasive to buy or clean, however no surface profile is provided.

An ideal method of surface preparation for repairing localised areas of corrosion and coating breakdown using a combination of hand- and power-tools. Surface tolerant and "ultra" surface tolerant coating systems have been developed to be applied over tool prepared substrates whilst still providing exceptional long term corrosion protection and coating performance.