1075 hamon

S

Steve Beckwith

Joined
May 29, 2004
Messages
393
First time using 1075, I clayed the blade, when I etch I am getting these lines running parallel to the edge. I have etched with ferric chloride and hot lemon juice. Initially I thought it was decarb. I have ground this blade a total of three times, hand sanding to 400 each time. The lines actually seem to be getting worse. I am thinking this might just be a part of the steel. Steel is from Aldo. Any feedback would be greatly appreciated.

https://imgur.com/a/rJ4bZkx
 
It might be the image, but it looks like there is still a lot of decarb or unhardened steel on the blade. If the tip black like it looks, that is hard steel.
Tell us about your HT method and how you did the clay (type, thickness, etc.)
 
I've had streaks of oxide appear like that when lightly polishing. You can try a 3M pink sheet and polish over those areas to see if it comes off.
 
Another possibility is alloy banding. I've had similar appearance show up on some 1095 that I've etched.
 
For clay I have used Sairset. I thin it out to mayonnaise consistency, apply no more than 1/16" thick. I have used Sairset primarily because I have quite a lot left over from my kiln and glass furnace building days. I have always had good results in the past but this is the first time I have used 1075.
 
Alloy banding. I couldn't think of the proper term. It seems to becoming more pronounced as I grind and sand. Heat treated to 1480F, quench in Parks 50, tempered at 375 twice, 1 hour each time
 
Out of curiosity did you do any pre treatments to the steel before Aus? Most of Aldo's carbon steels come in a spheroidized state, which makes for easy machining but is a less than ideal state for directly Austenitizing. I usually do a DET anneal beforehand to break up the spheroids. Here's a link to Larrin's article regarding this topic if you want to check it out.
knifesteelnerds.com

How Annealing of Steel Works - Subcritical vs Transformation Annealing - Knife Steel Nerds

How and why annealing works including the differences between a subcritical anneal and a transformation anneal. Which is faster?
knifesteelnerds.com knifesteelnerds.com
 
Just to take a step back and get some details in your process before looking at the steel, for your hand sanding what grit did you start with and did you change directions with each grit to ensure all low grit scratches were out? You say you used ferric at some point in your etch how long did you etch in ferric and what is your ferric solution, how many parts ferric to water.
 
Not that you can't harden a blade without the pretreatments, I find that it helps refine the grain and hardens a bit better.
 
All good questions. I belt sanded to 240 then hand sanded 220, 320, 400 but I have not changed direction as I move up to the next grit. The ferric is diluted with distilled water at 5/1. Etched for approx. one minute then spray with Windex then wash with hot soapy water. I have also been using hot lemon juice and a 1500 grit schotchbrite type scuff. I have used this complete technique on W-2 with excellent results. I have to think that I have fallen into some definition of insanity. I have now ground this blade and sanded it out 4 times, doing the same thing over and over and expecting different results. I will try changing directions between grits tomorrow and see if that will help.
 
Steve Beckwith said:
All good questions. I belt sanded to 240 then hand sanded 220, 320, 400 but I have not changed direction as I move up to the next grit. The ferric is diluted with distilled water at 5/1. Etched for approx. one minute then spray with Windex then wash with hot soapy water. I have also been using hot lemon juice and a 1500 grit schotchbrite type scuff. I have used this complete technique on W-2 with excellent results. I have to think that I have fallen into some definition of insanity. I have now ground this blade and sanded it out 4 times, doing the same thing over and over and expecting different results. I will try changing directions between grits tomorrow and see if that will help.
Click to expand...
The reason I asked is the lines look more like coarse sanding scratches, take your 400 and sand diagonally to the current lines and I bet you’ll see coarse marks right away that are stubborn to get out, if that’s the case drop to 320 and sand diagonal until all lengthwise lines are gone then switch to 400 lengthwise till all diagonal lines are gone.
 
I personally take my blades up to 320-400 then hand sand with just 400, makes it easier to know I’m at a 400 finish.
 
Also, it may take several etch and rinse cycles to start to get some topography. I etch for up to 10 minutes on damascus. It is best to over etch since you are going to lightly sand it back.
Once you have some topography, put some very fine paper (1000 grit or higher) on a hard block and work the surface. It will polish off the high spots bright while leaving the valleys dark. Work it down to where you like it and quit. Wipe off the sanding swarf regularly so it doesn't build up in the valleys and start to rub the dark away.
My final treatment is a very light rub with Mothers Polish or Flitz. Just a tiny bit worked into a soft cloth.
If any step messes up, just go back and etch again and try once more.
 
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So I thought about this over night and decided to eliminate my sanding technique. This picture is a 240 grit grind then directly into hot vinegar. You can see that my grinding is 90° off of these lines. I think I am going to bag the idea of a hamon on this one.
https://imgur.com/a/34nnbe1
 
I don't think you necessarily have to give up on the hamon even if there is alloy banding. Here's a post on the subject from a few years ago where Don Hanson shows some of his work that illustrates it. It doesn't detract from the appearance to my eye.

Alloy banding / Carbide segregation

As by request......What is the difference between alloy banding and carbide segregation? I haven't researched this much, but was under the impression they were the same thing. As Mete pointed out in another thread, "Banding is due to the mechanism of solidification of the molten steel !! Very...
www.bladeforums.com www.bladeforums.com
 
That link shows some really nice blades made with steel that has almost a damascus like alloy banding. My steel makes it look as if I have done a poor job of finishing the blade. I'll look at the blade again tomorrow and decide where to go from here. Thanks all for the feedback.
 
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