Need help from the hamon guys

i4Marc

i4Marc

Joined
Oct 19, 2011
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Ok, here are the details. This is Aldo's 1084. I sanded the blade to a very clean 1200x. I used Nick Wheeler's method from his old etching video and applied the etchant to the blade using a blue shop towel wrapped around a well washed plastic stick secured with a rubber band. The etchant was heated in a stainless tray on a hot plate with dish soap. I did 4 cycles with white vinegar and 4 cycles with lemon juice. I kept the applicator moving. Both sides got equal wetness and exposure. I removed the oxides with 1500x loose abrasive mixed with 3 in 1 oil applied to a felt pad mounted to a pine block. I cleaned everything meticulously beforehand and was very careful to keep contaminants away from the operation. When I got into the etch and polish cycles I started noticing what looked like scratches in the blade. I wasn't expecting a W2-like hamon with 1084. The overall look of the pattern is not the question. If you notice in the photo, the boundaries of the clouds look like they are being dragged side to side. It would be like putting paint on a surface then dragging across it with a dry brush. So my question is why am I getting this particular phenomenon? It's almost like the acid traveled along the micro scratches in the finish and etched along the grooves. But The blade was well saturated and the agitation was constant. This is my first attempt at a hamon so all the supplies I used were new and clean. Will attempting to sand out these striations wipe out whatever hamon is there?

I guess as long as I have your attention I might as well ask, what am I missing as far as getting more darks/better contrast? Can you scrub too hard when removing oxides? I didn't scrub that hard but maybe you have to be delicate about it?


 
For more darkness and visibility, etch a bunch more cycles... or, etch in 4:1 water/ferric chloride for a minute, neutralize, scrub oxides, do that a few times until you get a good dark line, then scrub hard with powder and do a few more lemon juice etches.
That saves a lot of time, biting your etch in deeper before whitening. Or, you can leave it dark after the ferric. As for the lines, etching deeper may help, or sanding up to a finer finish may help. Typically I don't have that happen though, at even 1000 grit on W2.
 
That has been my experience with hamons on 1084 steel. I have done about 4 of them and they all had the horizontal lines through it.... And it wasn't poor hand sanding either.

I haven't figured out why yet, but it could be from rolling at the mill?

Here's one of mine. At least it looks unique...

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006_zpsytda6plk.jpg


ETA: etching longer only accentuates the lines. They definitely don't go away.
 
Just for curiosity, is it possible those lines showing any previous scratch pattern?
It could be a mill artifact or a work hardening footprint wich had showed through localized difference in hardenability.
If it is the mill i'm not sure, but if it is the latter a normalization step (Acm) will erase it. There is also a chance that low temp termal cycling will enhance it.
 
Shane, that is interesting. I thought it was just me.


Here is the HT info in case it gives you guys any more clues. The blade was normalized at 1600˚, 1400˚, 1250˚. Austenitized @ 1485˚ w/5 minute soak. Quenched in Parks 50. Tempered 5X @ 375˚ for 2hrs each. The extra temper cycles were for correcting warps. The lines shouldn't be revealing scratches from previous grits. I really try to get every scratch out at every stage. The 1200x was very clean. If this is just a structural feature of the steel or HT then fine. If I need to do more work then that's what I have to do. I'm ready for glue up but I don't want to go into that stage with a half-assed job on the blade.
 
Then my guess is if you remove the subcritical 1250° step you'll get probably rid of those lines; either this or increasing the soak time at 1485°C just a bit.
Only if you want to remove those lines, there is nothing wrong with them in my opinion.
 
Looks a lot like carbide banding. Could be due to your thermal cycling. Could also be a rolling mill artifact. I've had 1095 do the same thing to me...
 
If this blade is not going to be remedied by additional sanding at this point I'm just going to proceed. But for the future, are there other recommendations for thermal cycling which will avoid this effect? I do all my thermal cycles, normalizing and austenitizing in an Evenheat KH418. The method I used was suggested to me by Stacy but I know there are a lot of you guys that have considerable knowledge on the subject. I'll post up the finished knife in another thread when it's done.
 
Well, I sanded it all out. I didn't particularly like this hamon anyway. It looks better as a ghosted pattern.
 
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