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ACID ZINC BLACK CHROMATE

WE HAVE JUST INSTALLED A NEW CHLORIDE ZINC BARREL LINE AND WE ARE HAVING TROUBLE DRYING PARTS THAT HAVE BEEN BLACK CHROMATED , OUR SPIN DRYER TENDS TO SCRATCH THE PARTS TO MUCH IS THEIR ANY OTHER WAY TO DRY THEM STAIN FREE? OUR BARRELS HOLD ABOUT 70 KILOS ANY HELP WOULD BE GREAT THANKS C.C.ANDERSON

Craig Anderson
- AUSTRALIA
1999

The only way we get around such problems is to place the work from the barrel around the edge of the spin drier so that it is not suddenly forced to the edge when the drier starts. We also start the drier gradually so that it reaches its maximum rpm more slowly. Most of the scratching occurs in the start up phase. Also don't run the drier too hot as this can damage the black chromate layer. We turn it down to 50 degrees C.

Simon Lee
- New Zealand
1999

Hi Craig, One effective way to reduce scratching is to dump the barrel into the drying baskets *before* the rinsing step.. then, using your hoist, dip the basket into a drum of water with a hose running into it at the desired rinse rate. I have found that by doing this, the greatest amount of scratching is eliminated. Also, the scratches you do see after drying may "heal" somewhat over time. Set some aside and look at them later.

Mike McDonald
- Jefferson, Wisconsin
1999