You can typically choose the best sandblasting pressure by reading the recommendations on the packaging of the sandblasting tip. Each sandblasting tip is designed with a specific air pressure. The amount of sandblasting pressure that is optimum for any given sandblasting tip is calculated to give not only the best sandblasting results, but the longest life for the tip. You are usually safe to use the sandblasting pressure recommended on the packaging without creating any problems with the tip or the item being blasted. Failure to adhere to the tip specifications as to pressure can often result in a prematurely worn tip.
Sandblasting is the process of mixing a blasting media, such as fine silica sand, with high-pressure air. The result is a stream of high pressure sand that will strip away rust, paint and oxidation, leaving only the bare metal behind. The process of sandblasting creates heat that can distort the metal being blasted if not properly controlled. This sandblasting pressure can also be used to create etchings on stone, wood and other materials, while different blasting media, such as baking soda, walnut shells or steel shot, will result in different types of finishes on the materials.
A sandblasting tip is typically manufactured from a material, such as ceramic, that will wear over time due to the sandblasting pressure pushing the abrasive through the nozzle as a job is being completed. The tip size commonly refers to the size of the opening in the tip, and each tip comes from the manufacturer with a recommended sandblasting pressure according to the type of blasting media that is being used. If you use a higher pressure than recommended, you run the risk of wearing the tip out far too early. This will result in a poor blasting pattern as well as a reduction in blasting pressure as the orifice becomes worn and allows more air than intended to escape the tip.
Many home sandblasting setups have maximum safe operating pressures listed with the kit and you should never attempt to use a higher air pressure with this type of kit. Conversely, using pressure that is too low will often result in poor performance from the sandblaster. Another way to regulate sandblasting pressure is to consult the packaging of the media type you are using. Most of the packaging associated with blasting media contains recommendations on air pressure according to the type of blasting that is being done.