plating, anodizing, & finishing Q&As since 1989
Chromium plating thickness per P-106 of MIL-STD-808
September 2, 2010
I have a requirement for chrome plating per finish P-106 of MIL-STD-808 (MIL-HDBK-808 [affil. link]). This spec calls for a minimum final plate of .025 mm (~.001") chromium per QQ-C-320 Type I, Class 1. However, QQ-C-320 (FED QQ-C-320 [affil. link])Class 1 says the minimum thickness should be .00001". So, I am wondering if this is a typo in MIL-STD-808 or if it should really be a thickness 100 times the minimum specified in QQ-C-320.Robert Byrne
Aerospace contractor - Stamps, Arkansas, USA
September 7, 2010
There is one very important phrase you missed out on the Class 1 thickness as specified in QQ-C-320 and that is "Unless otherwise specified". MIL-STD-808 is indeed calling up a thickness several factors higher than QQ-C-320. The minimum thickness called up in QQ-C-320 is what would normally be considered a "flash" coating, very thin, usually decorative rather than functional. A thickness of 0.001" is not uncommon for chromium plating, in fact it can be plated considerably thicker than that and often is when trying to refurbish parts.
Aerospace - Yeovil, Somerset, UK