Where the
world gathers for metal finishing
Q&As since 1989


-----

Pinholing on external and internal radius

We have recently installed a new magic booth powder system since installation we have been hit with the pinholing problem. We thought at first it was related to our pre-treatment plant so at the weekend we completely emptied and cleaned out the full system problem still exists. We tried painting with the manual gun and the parts were okay, but when we switch over to the robotic reciperators we get the pinholing, it is most common on the external and internal radiuses, has anyone come across this before.

Jim McCarron
Nichol Mckay metal Fabricators - Scotland
2005

---

2005

Hi Jim,

It sounds like you have your gun settings wrong. The effect could be "back ionisation", this is caused by either the guns being too close to the workpiece or the kV being too high. Another possibility is that the powder is simply too thick try turning down the powder throughput.

Hope this helps,

Drew Devlin
- Lincolnshire, UK