Recommendation? San Mai Finishes

Travis Talboys

Travis Talboys

Knifemaker / Craftsman / Service Provider
Joined
Oct 30, 2018
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443
I have been working on a set of San Mai kitchen knives (1084 center, 15n20 outer), and I'm now at the hand sanding and etching phase. I was curious what others are doing to finish out their blades. What grits do you go up to? Is there any post etch sanding? Does anyone recommend a coffee etch? I've etched other blades before, but this is the first time I am finishing a San Mai. These are to be a wedding gift, so I would really like to get the most out of the pattern.

Thanks in advance,
Travis
 
IMO, san-mai takes a lot of care/time to get right. There's a lot of carbon steel there that you don't want to clean the oxides off after etching. What I have done is treat it like regular damascus, etching long enough to get enough topography so that your sanding/polishing paper/stick doesn't touch the carbon steel. Then being really careful when cleaning off the 15N20, making sure to avoid the 1084. Then I do a coffee 'stain' as needed to darken up any spots where I hit the 1084 with the 5000 grit paper.

Another thing I've done in the past that was shown to me by a MS (but I'm not sure he still does this), is to neutralize the final acid etch in boiling baking soda/water and then letting it sit a day before cleaning off the blade. I can't say it doesn't help, but also can't say it does.
 
Travis Talboys said:
I have been working on a set of San Mai kitchen knives (1084 center, 15n20 outer), and I'm now at the hand sanding and etching phase. I was curious what others are doing to finish out their blades. What grits do you go up to? Is there any post etch sanding? Does anyone recommend a coffee etch? I've etched other blades before, but this is the first time I am finishing a San Mai. These are to be a wedding gift, so I would really like to get the most out of the pattern.

Thanks in advance,
Travis
Click to expand...
why did you use a hardenable steel for the cladding?

To finish out san mai laminated steel I do it in various ways

belt finish to 320 and cork belt polish at 400
hand sand to whatever you want
belt finish and etch in ferric chloride.
whetstone polish
 
weo said:
IMO, san-mai takes a lot of care/time to get right. There's a lot of carbon steel there that you don't want to clean the oxides off after etching. What I have done is treat it like regular damascus, etching long enough to get enough topography so that your sanding/polishing paper/stick doesn't touch the carbon steel. Then being really careful when cleaning off the 15N20, making sure to avoid the 1084. Then I do a coffee 'stain' as needed to darken up any spots where I hit the 1084 with the 5000 grit paper.

Another thing I've done in the past that was shown to me by a MS (but I'm not sure he still does this), is to neutralize the final acid etch in boiling baking soda/water and then letting it sit a day before cleaning off the blade. I can't say it doesn't help, but also can't say it does.
Click to expand...

HSC /// said:
why did you use a hardenable steel for the cladding?

To finish out san mai laminated steel I do it in various ways

belt finish to 320 and cork belt polish at 400
hand sand to whatever you want
belt finish and etch in ferric chloride.
whetstone polish
Click to expand...
Thank you both for the helpful information. I'm hoping to get a blade etched tonight or tomorrow. I'll post a photo when it's done.

To answer your question, HSC, 1, it was what I had, and 2, I have seen hundreds of examples of San Mai and damascus using those two steels. I didn't see any reason not to use them myself.
 
I cheated when I did mine, keep in mind these were around knives 10-12 I’ve made(so you probably shouldn’t do this). They are 1084 and 15n20 San Mai, I would do a standard etch then fine scotch-brite the blade which would leave the topography line where the steels meet then clear fingernail polish the 15n20. Repeat the ferric etch then coffee etch and lastly remove the clear nail polish.
A5A1ADA4-7F75-4E95-A950-A70D8A132B1E.jpeg
 
3fifty7 said:
I cheated when I did mine, keep in mind these were around knives 10-12 I’ve made(so you probably shouldn’t do this). They are 1084 and 15n20 San Mai, I would do a standard etch then fine scotch-brite the blade which would leave the topography line where the steels meet then clear fingernail polish the 15n20. Repeat the ferric etch then coffee etch and lastly remove the clear nail polish.
View attachment 1605023
Click to expand...
Cheating or not, they still look nice.
 
Here is my first attempt. I went with my normal etch, followed by two short coffee etches. It's not a great picture, but I'm pretty happy with the results.

20210723-120413.jpg
 
So I finished them. 1084 core, 15n20 cladding. The larger is about 13" oal with a 9" edge. The smaller is about 10" oal with a 6" edge. Both have stabilized curly maple handles with black G10 liners and separators.
20210731-183636.jpg
20210731-183708.jpg


I had fun finishing these. Thank you everyone who advised me.

Travis
 
Jesse Lange said:
Travis, what was your grinding/ sanding process before and after etch?
Click to expand...
After a lot of research, I found that my usual process wasn't too far off. I grind to 220, then hand sand from 180 up to 800. Then it's into the FC for 4 or 5 cycles totalling no more than 15 minutes, rubbing lightly with a very worn piece of 1000 grit to remove the oxides. That brought out the transition line, but not a lot of contrast. I added 2 45 minute soaks in coffee to make everything pop, again sanding lightly after each soak.
 
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