Talk:Master Armorers/@comment-47.72.43.1-20170604070938/@comment-84.231.26.220-20170807091423

Acid is used as part of some heat treatment (=hardening) processes, although it is used for cleaning, polishing and of course corrosion protection (so simply for surface prosessing). It can also have an affect on surface hardening and after treatment cooling. Heat is what does the hardening, different temperatures and cooling solutions and timeframes are used for different end results and usage scenarios.