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Old 28th May 2020, 06:30 PM   #1
Interested Party
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Join Date: Dec 2019
Location: Eastern Sierra
Posts: 171
Default A little polish in the time of COVID

In December 2019 I had a question about a kindjal. The answers were inconclusive, but it was a great learning experience. I am sure in time I will find what I was looking for. Thanks to everyone for their help. Ariel in post #8 wrote, "Also, Caucasian often used a technique of differential tempering, deliberately hardening edges and leaving the body soft. Kind of like nihonto. This can be seen after a good polish, and definitely after acid etching." Honestly I hadn't considered the possibility of a differential temper. The idea knocked around in the back of my head for a few months then Covid happened and as I work in tourism I have had a bit of time on my hands. I knew a good deal about polishing from working in my grandad's gun shop as a kid (that doubled as a knife shop for the grandkids. I ground and tempered my first blades at 12), but I never did the bluing, other than touch-ups with cold blue and acid etches I knew about in theory but we had never used them. So I studied up. There is a huge amount of information hidden in this forum and the keris warung kopi forum. I did some test etches with lime, vinegar, and coffee respectively on a few blades to see what would happen. The coffee technique I'm still working on. I polished the kindjal to 2000 grit using the method Jim Hrisoulas laid out in his chapter on Japanese Heat-treating and Polishing in his first book with the variation of a 4 /12" x 8" bench mounted sanding block for efficiency and safety. The blade was finished using three vinegar etches from the same chapter. The blade was polished using cerium oxide following each etch. Before each etching bath the blade was washed with soap and water, dried, and then cleaned with acetone. I found if I kept the vinegar moving by brushing the surface with a clean tooth brush I got a more even coloration. After each etch I neutralized the acid with a baking soda slurry. The slurry darkened the blade considerably. Sorry for the long winded introduction here are the results, followed by a question. The pictures begin with a sellers picture of the before condition. I wish I had taken my own, lesson learned. Then an intermediate picture from December. Next are two full length views of the finished product showing the differential temper, Ariel was right. Finally are two detail pictures of the blade.

Opps. The intermediate picture (its a horizontal view) seems to be the next to last in order proceeded by a vertical finished view. Sorry for the confusion with the pictures. I guess the order can't be controlled after all.
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Last edited by Interested Party; 28th May 2020 at 06:58 PM. Reason: clairification
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