SURFACE PREPARATION
Metspray can work with you to deliver the best solution for your surface preparation requirements, at your site or ours. There's no job too big, too small, or too complex.
Metspray has the expertise and the equipment when it comes to abrasive blasting. We have over 30 years' experience, understand the critical importance of correct surface preparation, and why using the correct abrasive media is paramount. Whether you’re restoring an existing asset or preparing a critical new asset, it all starts with surface preparation - the foundation to protective coatings that will endure the test of time. From a brush-off clean all the way to a white metal clean (Sa3/SP5), our team can work with you to profile your substrate ready for coating. Our East Tamaki facility is home to 3 abrasive blast booths with the capacity to accommodate the largest structures, up to 20tonne and assurance that work can move forward in all weather. For structures that can’t be moved, we have our expert site team that can perform your abrasive needs, whether dry, vapour, or UHP water blasting, to the same quality as if it was done at our facility.
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FAQs
What is sand blasting? Sand blasting, more commonly referred to as abrasive blasting (sand/silica is no longer used), is the process where a blast media, such as garnet or steel grit, is propelled at high speed through a nozzle at a substrate (surface). The purposes of this method are to remove corrosion, old coatings, and unwanted contaminants, or to provide a textured finish. Abrasive blasting is most commonly used to prepare the substrate for coating application.
Is abrasive blasting dangerous? No. Our team follow strict health and safety guidelines and wear specialised personal protective equipment to ensure they are kept safe. Up until 1958, sand (silica sand) was the industry-standard abrasive blast media. It was found to cause long term damage to the lungs, so was banned and replaced with safer blast media options like steel and garnet.
What materials can be abrasive blasted? Typically, abrasive blasting is used to clean and prepare steel. However, most other non-ferrous substrates such as aluminium, hot dip galvanised steel, stainless steel, and others can be abrasive blasted.
What types of abrasive media are there? The most common media used in New Zealand is either steel grit or garnet grit, as they are the most economical. These are typically used where a coating is applied over the substrate. Other types of blast media include ceramics, aluminium oxides, and walnut hull, to name a few. For a decorative texture, a bead blast media would typically be used, rather than a grit.
What surface preparation grades are available? Surface preparation of any substrate to the correct standard is of critical importance before coatings can be applied. Surface preparation can range from a light brush-off clean through to white metal, or a combination of surface preparations (usually for recoating existing structures). Typical surface preparation specifications in New Zealand include: •SSPC SP7 / Sa 1 ‘Brush-off Blast Cleaning’: Light blast clean and removal of loose rust/coatings. The most economical option for short-term coatings and low-corrosion environments. •SSPC SP6 / Sa 2 ‘Thorough Blast Cleaning’: Removal of tightly adhering rust or coatings. Offers a great balance of visual quality and affordability, with decent coating adhesion longevity in low-corrosion environments. •SSPC SP10 / Sa 2 ½ ‘Very Thorough Blast Cleaning’: Removal of tightly adhering matter and nearly all streaks and stains. Offers long-lasting coating adhesion in humid and marine environments. •SSPC SP5 / Sa 3 ‘Blast Clean to Visually Clean Steel’: Uniform metallic colour and removal of all matter, streaks and stains; even when viewed under a microscope. Maximises coating integrity and longevity for vital equipment in highly hazardous environments: such as chemical tanks, submarine vehicles, turbines, and more. •SSPC SP16 ‘Brush-off Blast Cleaning – Non-Ferrous Metals’: Light sweep blast clean to remove all foreign matter and loose coatings, to prepare the substrate for liquid coating. Must use non-ferrous blast media such as garnet or ceramic. These are the most common standards, however there are many more, each to be used for specific substrates and service environments. Contact us to determine the correct method for your project.