Media blasting is a great alternative to sanding and chemical treatments, giving parts an even finish with less labor and no hazardous waste. However, there’s more to blasting than just hooking up the gun and aiming it at a part: good performance requires the right combination of equipment and technique.Envirosystems Group offers StripMaster media blasting equipment, giving you a wide range of media options in a platform that includes media recovery and uses less energy than other models on the market. Getting the most from that equipment means making the right choices when choosing a blasting setup and using it.
Match the compressor with the blaster
If there’s too little pressure, the media won’t be striking with enough force to remove material. If there’s too much pressure, the media may disintegrate and the blaster tank could burst. Most blasters need a consistent 80-100 psi to work properly.
The compressor should be big enough that it can keep up with the demands of the blaster without having to run constantly. Not only does this cause excessive wear, the added heat increases the amount of moisture mixing with the air.
Keep water out of the system
For other duties, moisture is a minor annoyance, gradually filling the compressor tank and reducing total capacity. When it meets with the media, it can form clumps, clogging the blaster. Adding an in-line filter is inexpensive yet it can have a drastic effect on the blaster’s performance.
Minimize hose length and bends
Friction inside the air hose decreases pressure, so it is best to have as little hose as possible between the compressor and the blaster. If the hose needs to stretch over a wide area, opt for one with a large diameter. For example, air traveling through 20 feet of 1/4 inch hose will experience an average drop of 34 psi, while the same length of 3/8 inch hose will only see a drop of around 7 psi. Likewise, the straighter the hose is, the better it will be at maintaining pressure. A single sharp bend can result in a pressure drop as high as 10 psi.
Adjust the blaster media valve
The blaster has two valves that open when the trigger is closed: one from the air hose and one from the media tank. Both have adjustment screws, but it’s usually the media valve screw that keeps the blaster from being effective. To get the best performing mixture, open the media valve until there’s just enough mixing in with the air to remove material. This ensures there is enough media to do the job without causing decreased velocity from putting too much media in the air stream. The screw should be checked and readjusted each time the part or media is changed.
Use proper technique
Damage caused by media blasting is almost always the result of improper blasting technique. Thin sheets warp because enough material is being removed that it loses structural rigidity, and even the thickest part will have an uneven if over blasted.
Just as spraying paint in one spot will cause runs, aiming the blaster at one spot will cause surface damage. To get a smooth surface, media should be applied gradually. Keep moving back and forth over the part keeping the nozzle tilted at an angle between 40 and 60 degrees toward the direction you are moving for wider coverage.