Media Blasting is a pretty simple process when you break it down into the basics. You mix an abrasive media with high pressure air and shoot it out of a small orifice in a gun/nozzle. Media blasting is extremely effective if you make sure you follow some fairly simple tips. In this tech entry we will cover the basics you need to follow when blasting with a pressure blaster.
1. Proper Equipment- The number one thing that will cause a media blaster to work incorrectly is a compressor that can't keep up with the blaster. Be sure to check the ratings of the blaster you are purchasing (or own) against your compressor. Ideally you do not want your compressor to be at max capacity when running the blaster. Constant running of the compressor without rest causes excessive heat which creates moisture in the lines and can cause clogs in the blaster (another reason to have a proper Air Management System). Remember that media blasting requires a high amount of constant pressure to work effectively and if your compressor can not produce the volume required, the blaster will NOT work correctly.
-The industry standard for pressure at the nozzle is 80-100 PSI. Less than this and the media will not have the force needed to properly remove material. Running much higher than 100-120 PSI can exceed the blaster tank maximum pressure and cause the media to disintegrate when it hits the surface and reduce the cleaning abilities.
2. Hose Length and Shape- While it's nice to have a long air hose that can reach anywhere in your shop or driveway, it can drastically hurt the performance of your media blaster. Try to keep your hose as short as possible and free of any bends or kinks. Excessive lengths and bends can cause the compressor to work harder and decrease performance. Keep the same tip in mind with your blaster hose. Every loop or hard bend in the line will cause a significant drop in pressure (we've seen 5-10 PSI for every hard bend or kink in the blaster hose).
3. Water Is The Enemy- We hinted at it above, but we can't stress enough how important it is to have a proper air separator or dryer in line on your compressor. We suggest adding a new Inline Disposable Air Filter each time you start a new blasting project. They are cheap insurance to avoid those wet clumps of media blocking up your pressure blaster.
4. Properly Adjust Blaster- Most pressure blasters have similar deadman-style valves that block air or media. These valves do not always need to be opened fully. Each media/nozzle combo and job require different settings. A general rule of thumb is that your air to media ratio should be 90/10. Too much media will kill the end media pressure when it leaves the nozzle. We suggest doing a test run and slowly open the media valve until just after it starts removing material off of the test piece.
5. Technique- One negative thing that often gets said about media blasting is that it can warp thin panels and actually damage parts by removing too much material. This can usually be chalked up to improper technique. You want to have a steady side to side movement when blasting. DO NOT stop and blast in one concentrated area for any long period of time as it can warp thinner panels and remove too much material on some surfaces. Additionally, keep your nozzle at a 60-45 degree angle and aimed in the direction you are moving when blasting. This will help the media clean more efficiently and helps avoid sitting in one area for too long.
Follow these tips and make your blasting jobs go as smooth as possible and do the job right. If you have any further questions about blasting feel free to send us a message or jump onto our forums and join our technical discussions!