Sandblasting is a successful method of stripping away paint, dirt and finishes from a concrete surface. It involves the use of compressed air to spray sand at the concrete surface. This removes paint and all finishes straightaway. For DIY enthusiasts, always check with your sandblaster manual to ascertain the right type of media to load the sandblasting equipment with, given that various concrete surfaces require unique forms of sand grit. Additionally, the manual will also inform you of the correct air valve setting to use according to the target surface. This article explains how an ordinary person can use a sandblaster to strip of old paint from concrete walls possibly for a new paint job.

What you'll need

• Safety goggles
• Respiratory mask
• Work gloves
• Ear protection
• Sandblaster
• Media or sand

Instructions

• First of all, put on all the safety gear mentioned above before you start operating the sandblasting equipment. Exposure to the dust particles from sand may lead to respiratory diseases so you want to avoid that and protect yourself.  
• Clear anything around the workspace that may be impacted by stray sand. Use a plastic sheeting to conceal any exposed surfaces adjacent to the concrete surface to keep them clean.
• Shut off the stopcock at the sandblasting equipment to enable you fill the tank using silica sand.
• Turn on the pressure washer or air compressor and leave it to pressurize up to your desired PSI or pounds per square inch setting. Remember to set the sandblasting equipment on a low pressure setting at the start.
• Point the nozzle of the sandblasting equipment at the concrete surface. Press the trigger on the nozzle and immediately sand granules will be jetted out with the force of the air compressor, and will start to strip of the paint.
• Sandblast the concrete surface from the top to the bottom section for equal coverage.
• Slowly increase the PSI setting on the sandblasting equipment until the surface is free of paint or dirt. Keep the nozzle of the sandblaster continuously sweeping across the concrete surface to avoid concentrating too much on a particular area and resulting in damage. Use only short bursts of sand for specifically difficult areas.

• To switch off the sandblasting equipment, let go of the trigger on the nozzle and turn off the sand valve. Detach the air compressor from the blaster once you're done.

Note that sandblasting is a messy job, so protective clothing should be worn during the entire process.