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Q&As since 1989


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Metallic Powder Build Up

What is the best method to prevent or minimize build up (globs) of powder on the nozzle when spraying metallic powders?

David Turnipseed
aluminum - Louisville, Kentucky
2005

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I don't know what you've tried yet, so my suggestions might seem obvious. Turn down the kv's, turn down the flow rate of the powder, clean the tip of the gun often. Metallics tend to cover very easy, so it might take some experimentation to find out how low you can run the kv's and flow rate and still maintain productivity with out creating rejects. The build-up on the tip is going to happen to some drgree no matter what you do, so maintenance on the guns has to be increased when you run metallics. That glob doesn't come off with compressed air either, somebody has to remove it manually.

Sheldon Taylor
supply chain electronics
Wake Forest, North Carolina
2005

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David: I sold powder coating for a number of years, and found that some of the guns on the market would not spray metallics very well. I do not want to name names, but if the suggestions above don't solve your problem, you might invite another manufacturer in to do a demo spray. If you keep trying, you will find one that works.

Daryl Spindler, CEF
decorative nickel-chrome plating - Greenbrier, Tennessee
2005

You might look at the type tip you are using sometimes the tip can cause this I prefer to use flat jet nozzles. KV can cause this also. but by reducing kv you also run a chance of changing the color and or appearance of the product. You might try to blow off the tip when possible. make sure your gun is set up to spray metallic sometimes you have to change out the inside tubes on some units to spray them.

Mark Leichner
powder coating - Fayetteville, Arkansas
2006

DEAR, MAYBE YOU ARE USING THE ELECTRICAL TYPE OF POWDER SPRAY MACHINE. PARTICULARLY IN THAT TYPE OF MACHINERY THE CHARGING UNIT IS BUILT IN THE PANEL. YOU HAVE TO GO FOR THE ELCTROSTATIC EQUIPMENT. IN THIS EQUIPMENT YOU WILL FIND THE CASCADE IS INBUILT IN THE GUN. ONE THING MORE YOU CAN CHANGE YOUR ELECTRODE MADE WITH CARBON.

SANJEEV SACHDEVA
- FARIDABAD, Haryana, INDIA
2006