Re-chroming die-cast has always been a bugger.

At Chrometech we tell you how to pre treat the die-cast before chrome-plating

Chrome-plating the second time around after it has been pitted is rarely successful.

Reasons being: As you polish or grind the pits away you are removing the fine crystal structure of the die-cast. The more you polish or grind away the top surface, the coarser the grain structure becomes. During the electroplating process, this coarse grain structure allows more of the electroplating chemicals to penetrate the die-cast. This then will cause gassing and you could experience the bubbling effect of the chrome-plating in matters of days. Building up the craters with copper, in most cases is not successful. Not only do you have the issues with the process chemicals being trapped but the di-electrical properties between copper and zinc will accelerate the corrosion.

Tomorrow I will write about our novel approach to re-chroming die-cast.