Black stain spreading on keris during vinegar cleaning

Jean · 10th March 2020, 11:18 AM

I have no real clues but just submit my personal comments and opinion:
. The blade cleaning is not complete (remaining rust spots) probably because the vinegar is too diluted. I am using undiluted vinegar at 8-10% and I cover the vertical container for avoiding evaporation of the volatile acetic acid. The cleaning procedure usually lasts 24 h only with 2 intermediate brushings.
. From the pics, the black spots look like exposed and corroded steel or iron. As said by Alan in the last thread, the blade has pamor sanak.
. Is the bad smell like rotten eggs? In this case it would be hydrogen sulphide caused by the presence of iron sulphide in the metal and attacked by the weak acid.
Regards

10th March 2020, 11:18 AM	#2
Jean Member Join Date: Jun 2009 Posts: 1,740	I have no real clues but just submit my personal comments and opinion: . The blade cleaning is not complete (remaining rust spots) probably because the vinegar is too diluted. I am using undiluted vinegar at 8-10% and I cover the vertical container for avoiding evaporation of the volatile acetic acid. The cleaning procedure usually lasts 24 h only with 2 intermediate brushings. . From the pics, the black spots look like exposed and corroded steel or iron. As said by Alan in the last thread, the blade has pamor sanak. . Is the bad smell like rotten eggs? In this case it would be hydrogen sulphide caused by the presence of iron sulphide in the metal and attacked by the weak acid. Regards