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Thread 202/78
Pickling without hydrofluoric acid
Q. Has anyone got a recipe for a commercial strength cold stainless steel solution,without using hydrofluoric acid?
Rob Atkinson- Newcastle upon Tyne
2003
publicly reply to Rob Atkinson
SeeASTM A380 for pickling solutions. The usual substitution for HF is ammonium bifluoride, see letter 18607 . Commercial solutions usually also contain proprietary inhibitors, for which you may try the Chemicals link below. Ammonium persulphate+sodium fluoride was recommended for etching glass in letter 18787 .Perhaps, you can test this on SS and report back.
Ken Vlach [deceased]- Goleta, California

Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.
2003
publicly reply to Ken Vlach
I have been in contact with the technical department of the company who supplies my Electropolishing solution (Electropol 201). The solution is hydrofluoric free but does contain sulfuric. I am advised that I should pickle as per The Canning Handbook [on eBay, Amazon, AbeBooks affil links] for sulfuric anodising method. This will have great possibilities as there will be no need to passivate between processes. The only problem I can see is I will need to top up with sulfuric from time to time. Has anyone else used this method?
Robert Atkinson- Newcastle,Tyne & Wear, England
2003
publicly reply to Robert Atkinson
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