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#8 |
Member
Join Date: Aug 2014
Location: Germany
Posts: 525
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Hello,
my etchant is very mild. The strong contrast comes from the scanner. The pattern can be easily removed within a few minutes with sandpaper 1500 or 2000. If i would use a strong etchant, this would destroy the micro details. I use sodium persulfate (fine etch crystal) and a special technique, to bring out the finest details. It was a long way of experimenting. Compared to nital or nitric, sodium persulfate produce sharper details. 1: polish the surface up to a sandpaper grit of 3000. 2: etching with 20% Sodium persulfate (20Gramm (0.7 oz.)/ 100 mL distilled hot water) and a cotton ball until the result satisfy me 3: polish the surface again with sandpaper 5000 and 7000 or steel wool 000 + 0000 + Micro Mesh 8000 4: etching again with 7.5% Sodium persulfate (7.5 Gramm/ 100 mL distilled hot water (~50°C)) 5: polish the surface with Micro Mesh 8000 and 12000 to a mirror finish (in this case). The complete pattern is only visible under direct sunlight (the best way), halogen light or with the scanner. Try it out, you will be surprised. A nice side effect, Sodium persulfate is a very effectice rust remover. The color contrast is not so good, FeCl is better, but after some bad experiences i will never ever again use FeCl on antique steel because it creates a kind of moon surface full of pitting under the microscope even when used with low concentrations (~5%). Thanks for the pictures and comments. I also think, it is a three layers construction with hard steel in the middle, like japanese san mai. Kind regards Roland Last edited by Roland_M; 24th May 2015 at 12:59 PM. |
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