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Exact process for etching San Mai?

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by JG Custom Metal Works, Mar 16, 2017.

  1. I've searched a lot online and have t been able to find a lot of specific information regarding the actual time you're supposed to leave the blade/billet in the etchant.

    Also, I've found various opinions regarding the ratio of distilled water to ferric chloride. As far as the mixture is concerned I think I've settled on using 3:1 distilled water:ferric chloride. Unless I was reading his post wrong, Ed Caffery said that's what he uses. I would be interested in hearing other opinions in regards to the mixture ratios. For instance I've read that some folks use vinegar with their mixture.

    So, if you guys could describe your exact process for creating San Mai, after the blade is finished, I'd appreciate it. More directly:

    What grit do you finish your blade to before etching San Mai?

    What is your ratio or mixture comprised of?

    How long do you leave the blade in the mixture?

    What do you do once you take the blade out?(sanding, scotch bright, polishing, etc...)

    Do you use bluing solutions? Cold bluing, plum brown barrel finish, birchwood casey finish solution, etc?

    If you do multiple etches, what do you do in between the etching cycles?

    What do you do after the last time you remove the blade from the etchant solution? In other words, what it your final process for completing the San Mai finish?

    Help would be greatly appreciated.
     
  2. kuraki

    kuraki KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 17, 2016
    The reason the answers to your questions are so variable across the net is because A) the desired appearance is wildly different from one to another and B) a lot of it doesn't matter or the variables are so widely dispersed no answer will be perfect for your case. 3 to 1 or 6 to 1 dilution, how long to etch? Less important than the temperature of the solution, for example.

    The other questions really depend on what materials your laminate is made from and what desired outcome you have. What do you want it to look like?
     
  3. HSC ///

    HSC /// KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Nov 7, 2012
    I use 3:1 FC, this seems faster than straight solution.
    just dunk for a few seconds
    then neutralize,

    that's as simple as I do it,
    this is for the Japanese laminated steel I purchase.

    I'm checking in here with this because I do get some staining or discoloration and want to hear the process of others.
     
  4. Tom Lewis

    Tom Lewis

    Feb 24, 2000
    [​IMG]

    My method is to sand to 1000 grit, then dip in 3-1 FeCl for 30 seconds. Neutralize with Windex and baking soda. That's it.
     
  5. Oh by the way I'm using 15n20 with a 1084 core.

    Thanks for the info so far gents, I appreciate it! Those are some of the answers I was wanting too. Especially the less complicated ones :D

    That's an awesome looking knife Tom.
     
  6. kuraki

    kuraki KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 17, 2016
    That should give good contrast.
     
  7. Karl B. Andersen

    Karl B. Andersen KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jul 27, 2003
    I etch 3-4 times for 20-30 seconds per etch. Cleaning in between.
    Stainless San-mai will have different results than all simple carbon or all stainless versions.
    The amount of manganese in the core steel will etch black more or less depending on alloy.

    [​IMG]

    [​IMG]

    [​IMG]
     
  8. Truly stunning Karl. Do you have a layer of something in between the carbon and stainless? Perhaps a small layer of nickel?

    I hadn't ever considered Bakelite for handle material. Now that I think about it, I've never had an ak-74 magazine break on me. :D.

    I'm not sure if you have or not already, but I bet you could make a killing if you did a how-to video on take downs. Courses too.
     
    Last edited: Mar 16, 2017
  9. Karl B. Andersen

    Karl B. Andersen KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jul 27, 2003
    That shiny layer is the 1095 that the carbon migrated FROM to the carbon deficient 410 stainless. After the welding process, it's rendered just basically raw iron.
    My You Tube channel has extensive videos on how I do take downs.
     
  10. Salem Straub

    Salem Straub KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Oct 20, 2008
    Here's a few examples of things I've been doing... you can see that 304/52100 is more plain tu-tone than Karl's nifty 410/1095, as carbon migration does not much occur.
    These are 304/52100 (big ones) and AEB-L/CruForgeV (small ones.)
    [​IMG]

    304/52100...
    [​IMG]

    304/52100...
    [​IMG]

    [​IMG]

    [​IMG]

    My process is to hand sand to 600 or 1000, etch a minute or so in 4:1 water/ferric chloride, windex neutralize, water rinse and wipe dry. Then warm blade up to 130f or so over a burner, and rub turbine oil onto it. Rub oil off, warm again, rub a bit more oil on, warm again, lightly wipe off. This seems to darken the oxides some and keep them that way. For culinary blades, I use coconut oil for this step.
     
  11. Awesome knives Salem. Thanks a bunch for the info.

    Once I get this high carbon San Mai thing down, I want to start doing some stainless and high carbon. I'm kind of handicapped in that I don't have a press or power hammer. I've been dry welding all the way around my billets though and it seems to make it easier to set the welds by hand(and anvil/hammer).

    Not to get off topic but I currently have a billet(15n20/1084) dry welded up that's about 16" long. It's too long to fit in my forge all at once. It will fit through the rear port of the forge though. Would it be best to try and heat the entire piece and set the welds by hand all at once, or do half at a time? I also thought about possibly welding a couple 18" plates to the jaws on an extra leg vise I have, and use that as a manual press... then I could just heat the billet to temp in my Evenheat oven and press it together with that. Do you guys think a blacksmith leg vise would be able to squeeze a billet enough to set the welds, if I had thick plates welded to the jaws? It would be a dry welded billet.
     
  12. kuraki

    kuraki KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 17, 2016
    I don't think you'll get enough squeeze in your vise.

    I do think since it's welded you would work from one end down to the other.
     
  13. Salem Straub

    Salem Straub KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Oct 20, 2008
    I concur, that vise rig won't give you enough pressure over such a large surface area. Better bet to do two or three overlapping welding heats for the length.
     
  14. Awesome! Thanks a bunch guys, I really appreciate it.
     
  15. Pittknife

    Pittknife KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    872
    Oct 1, 2013
    It all depends on the san mai and heat treat, it really varies per san mai.

    But I don't use FC for san mai I use muriatic. I don't like the cleanup on FC, if I did use FC it's 40% FC, 30% distilled water, 30% white vinegar.

    Either way I take the blade up to 2-3k grit. 2k off the grinder, start hand rubbing at 600-800 grit and hope no deep scratches then I dunk.


    I stopped at 800 grit on this one though.
    [​IMG][/URL][/IMG]
     
  16. Salem Straub

    Salem Straub KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Oct 20, 2008
    Looks like commercial stainless damascus san mai? Mike Norris or someone like that? I've heard muriatic works well with etching stainless blends.
    Cool blade!
     
  17. kuraki

    kuraki KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 17, 2016
    Salem have you parkerized any of your stainless san mai, or only the damascus? I'm curious what a parked one would look like.
     
  18. Salem Straub

    Salem Straub KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Oct 20, 2008
    I've been thinking about it. I may try it on a small one. The transition zone could end up looking odd, though. I think I'd only try it on 304/whatever, not with AEB-L or 410.
     
  19. kuraki

    kuraki KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 17, 2016
    Yeah, that's what I'm most curious about.
     
  20. Which stainless steel is easier to use with a high carbon core? 304 or 410? Where are you guys buying the stuff from? Is it possible to dry weld and and the set the weld by hand? Obviously smaller billets would be easier to do by hand.
     

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