Foil fail?

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by Pelagicfun, Sep 9, 2019.

  1. Pelagicfun

    Pelagicfun Gold Member Gold Member

    244
    Oct 16, 2017
    Hey there guys. So this was my 2nd ever batch of aebl and I assume this was caused by my tool wrap packs not being sealed well enough. So since I have never witnessed anyone else's stainless fresh out of foil I'm not sure if this is ok or not. I use a hard rubber roller for veneer to seal them. I'm guessing no coloring is great but what is acceptable and what would a big fail look like? Should these 2 be fine after the surface is ground off?
    Thanks
    CC Screenshot_20190909-080321_Gallery.jpg
     
  2. Big Chris

    Big Chris SAHD/Knifemaker Knifemaker / Craftsman / Service Provider

    Apr 1, 2010
    Your top two blades packets likely had a very small pin hole.
    That compromised the atmosphere inside the packet and allowed decarb to occur.
    I know it has happened to me several times as well as to many others.
    I'd say they will be just fine because by the time you get the tips ground in you will be under any decarb that occurred.
     
  3. daizee

    daizee KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 30, 2009
    Yeah, some burning near the tip.
    Just the color is super shallow, but looks like there was intrusion right at the tips. The sharp corners there can pierce the packets - since they're not ground already, it would make sense to knock off those sharp points. Maybe grind your lead-in bevels before hardening.
    Did you put anything in the packets to burn up atmosphere, or coat the blades at all?
     
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  4. Pelagicfun

    Pelagicfun Gold Member Gold Member

    244
    Oct 16, 2017
    No coating or tissue. I will try tissue next time. I used Hoss's single oven recipe using the same foil for pre-quench and final quench. I am now thinking that the tip punctured the foil when I clamped in my plates on the first quench. Next run I will knock the edges off of the tip. My plates are mounted in a large vice. Maybe I shouldn't crank it down so hard on the pre-quench? Thanks for the answers and suggestions guys!
     
  5. JTknives

    JTknives Blade Heat Treating www.jarodtodd.com Knifemaker / Craftsman / Service Provider

    Jun 11, 2006
    I NEVER put anything in the packets to burn up the oxygen. Some times the the off gas can swell the envelope and cause other problems. What most likely happened is as you where rolling the packets and handling them the tip of the blade compromised the foil. We have seen it here in our processing. You get in a rush and it’s super easy to poke that sharp corner into the foil. We cut the end off the packet and save it for a shorter blade. But that being said your steel is file. With as short a soak as aebl requires and such a small hole that will clean up easily. What happens is the foil try’s to breath with the cycling of the oven. Oven turns on and pouch expands as the remaining gas expands. Oven turns off and the pouch collapses as the gas shrinks. It’s not much movement but if you got a sharp corner digging into the foil then it will work through and now that pin hole sucks air in and blows it out every oven cycle.
     
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  6. Pelagicfun

    Pelagicfun Gold Member Gold Member

    244
    Oct 16, 2017
    JT you are saying that after a good inspection of a packet it's ok to get a second use out of it? That's a great bit of information.
     
  7. Stacy E. Apelt - Bladesmith

    Stacy E. Apelt - Bladesmith ilmarinen - MODERATOR Moderator Knifemaker / Craftsman / Service Provider

    Aug 20, 2004
    That will almost surely grind out in the finish work. I see that when the foil isn't sealed well. In most cases it is insignificant. The decarb layer is pretty shallow.

    Use a double fold to seal the packets. Take a rubber mallet and gently pound the first 1" wide fold flat. Fold it a second time at 1/2" and pound snug again. Don't hit the blade in the packet when doing this or it may poke a minute hole in the foil.

    Don't put anything in the packet. If it is flat, snug, and sealed, the oxygen inside will be used up quickly with all the surfaces ( foil and blade) that any amount of decarb will be so insignificant it doesn't matter.
     
    Scaniaman likes this.
  8. daizee

    daizee KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 30, 2009
    Yeah, I reached the same conclusion about sawdust/paper in the packet. Causes inflation, but also changes the color of the steel surface, hence the question.

    Second quench?
     
  9. Stacy E. Apelt - Bladesmith

    Stacy E. Apelt - Bladesmith ilmarinen - MODERATOR Moderator Knifemaker / Craftsman / Service Provider

    Aug 20, 2004
    No, just finish it up. You will be fine.
     
  10. JTknives

    JTknives Blade Heat Treating www.jarodtodd.com Knifemaker / Craftsman / Service Provider

    Jun 11, 2006
    No, don’t reuse foil packets. I meant if you notice a hole in the end then we cut the end of the packet off and save it for a shorter blade and make a new one for that blade.
     
  11. Taqtaq

    Taqtaq

    69
    Jun 10, 2018
    Some times it looks really really good and you can just leave it. 5CFB04D7-5699-41AF-865A-D76B2F1AF011.jpeg
     
  12. Larrin

    Larrin Gold Member Knifemaker / Craftsman / Service Provider Gold Member

    Jan 17, 2004
    A little discoloration is just from air left in the packet. If you’ve got one area of the blade which is dark it is usually from a pinhole.
     
  13. Willie71

    Willie71 Warren J. Krywko. Part Time Knifemaker Knifemaker / Craftsman / Service Provider

    Feb 23, 2013
    I use a flat chainsaw file to knock the sharp edges off of the edges of the blade/tip to minimize pinholes.
     
  14. JTknives

    JTknives Blade Heat Treating www.jarodtodd.com Knifemaker / Craftsman / Service Provider

    Jun 11, 2006
    I do
    that on blade I surface grind. On the top I just hit it with the grinder. This allows me to slip a Titanimum shim under it to get it off the mag chuck.
     

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