Shot & Grit Blasting

Our Zinc Metal Spraying and Coating department undertakes shot-blasting and grit-blasting to ensure a clean surface prior to painting, metal spraying or galvanising.  Our blasting cabin is the biggest under cover in the Western Cape, being 5m x 5m x 30m long.

Zinc Metal Spraying operates under SABS ISO 2063: 1991 for blasting and metal spraying, and is also an ISO 9002 mark-holder.

We only undertake work that requires a SA 2½ or SA3 blast clean prior to over-coating.  The Swedish Standard (SA2½, SA3) relates to the cleanliness of the steel prior to painting or metal spraying.  A SA3 blast is a 100% white metal blast.  A SA2½ blast is a near (95%) white metal blast.

Normally, for a 25-40 µm profile, a machine is used.  The blasting is done with steel grit in an automatic process for unworked steel profiles such as IPE’s, beams, channels, angles and tubes.  This results in an SA2½ or SA3 shot blast.

Grit-blasting by hand operators is undertaken to SA2½ or SA3 for a heavier blasting profile of 50-75 µm. This profile is used for metal spraying where the bigger profile is essential, and for heavy duty coatings.  It is also used to remove heavy mill scale or rust on old steelwork prior to galvanising or painting.