1. One way you might see an instant clog in your abrasive line is if you touch your material with the tip of your nozzle. When this happens you will have too much back pressure against the flow of abrasive and it will cause the abrasive to get wet and back track up your line. When using a height sensor, check the distance between your nozzle and material.

2. If your breathers at your mini hopper are clogged or dirty, then the pressure that pushes the abrasive over the highest point of the whip will not be able to exhaust. This will cause the abrasive in your mini hopper to become pressurized and create extra force behind your abrasive flow going to your cutting head. The extra force will push more abrasive to your cutting head than necessary and could contribute to clogging issues.

3. You will notice abrasive blockages when your needle and seat start to go bad. As the slow drip of water starts to leak past your needle and seat, it will wick up the abrasive line causing the wet abrasive to block the nozzle and mixing chamber.

4. Occasionally you should clean the hollow breather tube located inside your mini hopper by removing the aluminum top and blowing compressed air through the hollow stainless steel tube. Sometimes when the abrasive in the bulk feed hopper runs out, it spits into the mini hopper with higher force causing some abrasive to go down the breather tube. When abrasive gets trapped in the breather tube, it blocks the air flow that is needed to neutralize the vacuum coming from your cutting head.

5. If you have a bad orifice or an orifice that is oversize or out of spec, it will cause the vacuum in the cutting head to diminish. This causes the abrasive to slow down and increases the probability of a blockage.

6. A bad mixing chamber can also cause your cutting head to lose vacuum. You will notice your mixing chamber is bad when you remove it and inspect the inlet water hole on the top. If the hole is larger than 0.090” then it is out of specification.

7. Another reason why you might be getting abrasive blockages is if your abrasive feed rate is set too high. When you change the orifice and nozzle to a smaller size it also means you have to turn down your abrasive feed rate. The abrasive feed rate to the cutting head might be more than the rate that is coming out of the cutting head and this will cause the abrasive to back up and block the flow.

8. It is also important to make sure that the abrasive inlet tube in the cutting head is tight with no way for air to leak around it or you will get a loss of vacuum. If you have the Accustream A2 style cutting head then you should insure that the secondary or opposite feed tube is properly blocked not allowing any air through if it is not being used.