Grit blasting is a surface treatment in which sharp grains (grit) are fired against a surface at high speed with compressed air or water, to clean, de-rust or roughen it. Grit is angular, broken blasting media; the sharp grains abrade away dirt, rust, paint or the cement skin.
Blasting media
There are many types of blasting media, each with its own properties:
- Grit — angular grains (steel grit, mineral grit) for powerful removal of rust and coatings
- Sand — once widely used, now restricted because of the risk of silicosis (quartz dust)
- Glass beads — round grains for a finer, more matte finish
- Granulate — plastic, nut-shell or corn media for soft, non-abrasive blasting
- Soda and dry ice — for environmentally friendly, gentle cleaning
Application
Blasting is used, among other things, for:
- Steel protection — de-rusting and preparing for paint or coating
- Facade cleaning — removing dirt, paint or graffiti from stone and concrete
- Roughening — improving adhesion for a new layer
- Restoration — carefully cleaning natural stone and monuments
The choice of media and pressure determines how aggressive the treatment is. On delicate substrates, soft media and low pressure are used to avoid damage.
Related Terms
- Blasting media
- Bush hammering
- Conserving
- Corrosion
- Natural stone maintenance
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