Making sure your abrasive metering valve is set properly is a simple process and will save you money in both time and abrasive.
How can you tell if your valve is set at the optimum setting?
Once your blaster is running and the deadman trigger is on, look at the abrasive flow coming out of your nozzle. An efficient air/abrasive mixture will be only slightly visible, appearing as a colored haze in the air stream.
If you see a lot of color in the air flow, there’s too much abrasive (and not enough air) in the mixture. Why? Your abrasive metering valve is open too far. When this happens, your cleaning efficiency is lowered, valuable abrasive is wasted and you’re losing money.
To get the perfect mix:
Wind the metering valve in to the fully closed position,
Now slowly open up the metering valve, until you can only just start to see the color change in the air exiting the nozzle.
That’s all the abrasive you need for fast and effective blasting.
PS to Garnet Users: When working with Premium Garnet abrasive and a Thompson Valve, 3 1/2 turns out from the fully closed position generally gives a perfect flow rate.