What is pickle and what is it for ?
Basically, the term pickle is used by jewellers to refer to an acid solution that is used to remove the black firescale that forms on alloys when they are subjected to heat Metal clay artists generally encounter firescale when sterling silver is in place or soldered on to fire clay pieces.
This is a process which chemically removes scale or oxide from steel to obtain a clean surface. When applied to bars or coils prior to bright drawing, the steel is immersed in a bath of diluted acids & heated to a temperature of around 800C. An inhibitor is added to prevent attack and pitting of the cleaned metal. After pickling, a washing process takes place followed by immersion in a neutralizer bath to neutralise any remaining acid. For environmental reasons shot blasting has largely replaced pickling.
For pickling process, big vessels are required to immerse the parts alongwith the same heating is required. The temperature around 600 C to 800 C is required & that is to be maintained during the entire process. So many prefers descaling than pickling.
There are different acids which can be used for the purpose of pickling. The different methods are used for different acids. But after pickling fresh water flushing & neutralizing is very necessary to avoid further acid attack & pitting on the metals surface. Many opt for passivation after the process of pickling to avoid further damage of metals.