Barrel Printout

Parts are sometimes "barrel plated". Plating barrels are constructed of plastic and have regularly spaced holes drilled through them -- the holes being big enough to let solution and current pass through, but small enough that the parts can't fall out through the holes.

If a discoloration or marking on the parts seems to match the hole diameter and spacing of the plating barrel, it is likely that the part was stuck against the barrel wall for some period, receiving high current density ⇦ huh? at the holes and little or none elsewhere. We call the pattern 'barrel printout'.

Barrel printout indicates that the movement of the parts in the barrel must be improved.