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Etching problems


steve bruechert

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First attempt at creating a hamon line.6" drop point 1075. Clay on spine heated to just past non magnetic cleaned scale polished up to 2000 wet sand. Etched using hot white vinegar soaked for 30 min.or so wiped clean re heated vinegar ..did this several times knife looks great from the spine to the temper line silky med grey tones & knife was very smooth to the touch ..but from temp.line to the edge it is much darker wich is good but looks like crackle paint finish and rough to the touch and very pitted ..why would this only be around temper line and not all over the entire blade 

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Hmmm...  I've never seen that before.  :huh:  It looks like over-etching, but 30 minutes in vinegar won't do that.  What is the complete heating history of this blade?  Could be decarb, and/or alloy banding, but I can't really say.

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11 minutes ago, Alan Longmire said:

Hmmm...  I've never seen that before.  :huh:  It looks like over-etching, but 30 minutes in vinegar won't do that.  What is the complete heating history of this blade?  Could be decarb, and/or alloy banding, but I can't really say.

I'm no expert on etching or hamon but given that the "orange peel" effect ends at the edge bevel starts, therefore it may have been ground off in the beveling, indicates (to my mind) that the steel got way too hot on the surface before the bevel was ground. 

What kind of clay

Did you differentially heat the blade before hardening 

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I had 80-90% of the beveling done before ht and basically just knocked off the scale after ht knife was beatiful but could not see the temper line at all. Would using ferric chloride be better option next time..just so strange that it only pitted along the temper line... pix are of same knife before etching the images where it looks gold is from lighting...first two show the clay 3rd is after knocked clay off, then various stages of polishing 

 

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So it's a stock removal and not forged? 

Any heat treating cycles before the quenching heat ?

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Well, clay looked wayyy too thick and too far down the blade. I would say the intire blade was critical when you quenched judging by the pictures (Not a bad thing). You took a picture outside of the forge, so I'm assuming this was a normalization attempt (very bad thing). I would guess you just grew your grains really big, and got alloy banding at the same time. 

Quite the quandary. 

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And, what I meant by "normalization attempt (very bad thing)" is that if you go over critical with clay on the blade, you run the chance of growing your grains. And if you go over critical for 3 cycles and let it cool to black heat on the visible steel you might still be at red heat under the clay. Going over critical for 3 cycles WITH or without clay will cause alloy banding. Aldo's 1075 I have found to be fairly finicky about the alloy banding. You really have to be careful. 

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1st pic was taken when i touched with magnet.  Was still sticking second was when it was non magnetic. Before i quenched clay was so thick cuz it expanded when it went in.  This is all trial n error well prob more error then trial ..but just dont have anyone to learn from so grabbed some bone yard steel which im not going to do again ..and rather then send the stuff out to ht id rather try to figure it out/learn to do it myself .sounds like 1075 not the steel for me to experiment with maybe 1080-1084?? And yes stock removal 

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I can believe that, some clays puff up. But the clay needs only be on the back 1/3rd of the blade. 

1075 works good usually, but It shows every flaw (and desired trait) after etching. That's why it's so popular in hamons. It's a good steel especially for a beginner. 

 

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1080/1084 is the easiest to HT on your own, but generally you won't get a hamon.  I would recommend doing a few knives without trying for a hamon, just to get that part down a bit more before trying to add something a little trickier.  Definitely learn to watch for decalescence and recalescence (and toss the magnet).  Also, what did you do to clean the blade prior to etching?  

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7 minutes ago, steve bruechert said:

The image where the knife looks gold is what the blade looked like before i put it in the vinegar nice polished finish ....And the very first image of the post that shows the pitting is what i got after etching in the vinegar & hitting it very lightly with 1500 wetsand paper 

I think what he's asking is: did you use any chemical cleaner, or soaps, or at any point apply any oils, waxes, polishing compound?

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Just washed with warm water w lil bit of dawn to clean & get rid of any oils etc. After that i made sure to not touch it..after last dip i washed blade in water/baking soda. Thats when it looked like crackle paint finish .Next day i just lightly wetsanded 1500 and seen that every where that looked crackled was actually pitted 

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Well, I'm perty well bumfuzzled by the whole canundrum. 

You got any immediate post quench pics? Did you notice any blistering? 

If you held it for 60-90 seconds after non mag, that's plenty of time to overheat a blade. 

As I said before, I think you have large grains, accompanied by alloy banding. Now, what would cause that to be visible after such a light etch? There is something else at work here I think. 

I can't say for sure, but whatever you did was obviously wrong. The best I can do is aid in any information you might need on how to do it correctly. 

Look up terms such as "normalization", and "decalescense", try and get an understanding of those two and the rest fall within.

As jerrod suggested, get your heat treatment nailed down before you go for a hamon.

Hope this helps!

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