The telltale etch.

Here you go Ebbtide. This is a good etch on chainsaw damascus.
 

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And this is a good etch on one of my camp knives. Notice the double lines which shows three separate zones of hardness. I was really proud of that blade. That's one tough knife. Forged from 5160. The blade was triple normalized, triple quenched and triple tempered. No spine draw.
 

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And here's a bad etch. It was my very first one and I didn't know anything about cable damascus or how to etch it. You can't see any zones at all on this blade unless you look very close.
 
Actually Max I can't see any lines on it at all. In fact I can't see the knife at all. You into real miniature knives are you? Or maybe I just missed it because it is hiding behind some of the words. :p
 
And last but not least, here's an etch that shows a heat treat that could have been better. But it doesn't really matter with this beast because it's 6150 steel. Anyone know about that steel? Wow! Is that ever a bugger to forge up!!! That blade is so tough it's hard to describe. I tested it like I do all of my blades by whacking on some hard white oak until my arm gets tired. No problemo with that steel. But you can see by the etch that my quench was too shallow. Room for improvement with most steels. Ask Craig if he's happy with it though. I think he is.
 

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Thanks Max for the great pictures. That second one really shows the temper zones on that blade. It also shows that they were very well done. I would be interested in knowing what you have learned about steel from etching your blades. In what way has helped you improve your blades?

I have never heard of anyone using 6150 steel to make knives. Sounds like a tough steel to work with.
 
I am finding that since I switched over to flat ground satin finish blades my errors show up big time. I have etched blades in the past but am finding that as I get to the 600-800 grit level the temper line shows up every time and every flaw.

Which is good.
I found it has helped me tremedously in being more aware of each step I take in making a blade. Etching definetly gives a maker a true read on his work and helps them be more honest with themselves.
I agree you can hide ALOT of mistakes and poor grinds under a Mirror polish or a bead blast.

I belong to a local knife club and in the past month or so I am spotting more and more mistakes in my own and other makers work. I never would have noticed a year ago. Many of them have been making knives for a number of years, me a little over 21mths.

Let me say I am greatful for all of the help I have recieved from the Forums. I have got my nose bloodied a few times but have learned from each experience.
 
Well Keith, etching my blades has done a number of things for my blade work. But the number one thing it has done is to tell me when I hit the heat treat right on the head. When I really scald the heat treat the lines tell the story. All I really do any more is edge quenches using a magnet for the non-magnetic quench. And the etch really tells the story quite well for an edge quenched blade. That camp knife is a classic example. When you get all three zones in full relief like that, you can rest assured that you hit the heat treat where it counts. It doesn't really say anything about grain size or rockwell hardness (to me, at least) but it tells volumes about your heat treating procedures. Those three zones are only apparent on blades that were in precicely the right temperature zone for quenching when the quenching took place. At least, that's in my experience. I don't know it all. Ed could probably tell you alot better than me. But that's what I've experienced.

6150 is steel from the heavy duty leaf and coil springs on semi trailers and trucks. That stuff is thick and takes some considerable forging down before it's suitable for blade stock. And it's fairly hot short or red short, whichever way you say it. It tends to crack all to hell if you let it get the least little bit above or below forging temp during the forging process. That last blade I posted is the only knife I've been able to successfully forge from 6150. You could say I just got a good scald on it is all. Or maybe I was holding my mouth right while forging. Hard to say just why it's so tempermental. But it really is difficult to work with if you haven't used it before. I'll definately use it again but it will most likely be on a special order requiring an extremely tough blade and the price will reflect the difficulties of forging it. It's hard to come by but it can be had at a few junk yards I'm sure. Good stuff if you have the patience for it. Wayne Goddard seems to like it. That's where I first heard about it. From his book, The wonder of knifemaking.
 
Thanks Max, I really appreciate your input here. I consider the information that you have suppied us with as being of great interest and I find most of those knives to darn nice as well (I am not a dagger fan).

I hope that Rex Walter does not mind me pilfering this quote from his thread, but I found that it would be of interest to those that wanted to know more about the Bausinger Effect.

The Bauschinger Effect
For both single crystal and polycrystalline metals,any change in the stress-strain characteristics that can be ascribed to changes in the microscopic stress distribution within the metal,as distinguished from changes caused by strain hardening.In the narrow sense,the process whereby plastic deformation in one direction causes a reduction in yield strength when when stress is applied in the opposite direction.
ASM METALS REFRENCE BOOK SECOND EDITION
WHEW-what a mouthful. In a nutshell what it means -in broad terms that relate to us- when material is moved enough to permently deform,thats the plastic deformation part,by forging bending etc.you lose ductility.Ductility is the reduction in yield strength mentioned in the last part. Kindof-Its not exactly the same but works for this example. If an edge is too hard it will chip when flexed on the brass rod test. Pretty simple in concept. The trick is to get the edge as hard as possible and then reintoduce ductility by tempering. This is what seperates the good ones from the also rans. Testing by flexing gives immediate feedback to the maker as to where this line is at.
If you don't chip edges at the begining of your experiments you are either not getting the maximum hardness possible or else you are overtempering. The trick is to sneak up on it a little at a time until you are satisfied with the results. After a few trials it is then possible to reproduce the results repeatedly. Different lots of steel will need to have times and temperatures adjusted . This makes it a good idea to work with known material. The learning cure will be much faster and you avoid the variables caused by material, which can leave you schratching you head wondering what went wrong.
Rex
Click to expand...
 
Max, thanx for the pics :cool:
Now it is all coming together ;)
This thread is a BF.C Classic!
 
Max: Thanks for posting the photos, it takes a lot of courage and honesty to post a photo of a knife that shows less than perfection. Your sharing brought greater understanding to our message. Etching blades is an opportunity for both the client and the bladesmith to learn.
This is why industry developed the methods and we all benefit.
 
Max:
Could you EXPLAIN why you say "Here is a Bad etch". I don't see it?:confused: :confused: ;)
 
Thanks Ed. It's really no big deal to me. Honesty is the best course of study in this craft. Keeping things honest with yourself and your customers is a must as you well know. Honesty with the general public like here is just as important. I have no shame in admitting fault. Like you said, it helps others learn by my mistakes and less than perfect results.

I'll take that as a compliment Ira :D

Actually, it's not a 'bad' etch. It's just a decorative etch. It has absolutely nothing to do with the quality of the steel in the blade. Only, how nice it looks. That's what I meant by a 'bad etch'. However, having said that, you can still see the 'quench lines' along the edges if you look closely. Cable damascus doesn't provide you with very noticeable quench lines in my experience. But that probably has more to do with my ignorance than any fault in the steel. I just haven't worked with it enough. That particular cable damascus was forged up by Russ Scheringer here on the forums. He lives next door to L6steel (Michael Cooper) in Florida. But he had nothing to do with the heat treating. That was up to me. One of the major problems with heat treating a dagger blade is getting a good quench on it without warping the blade. To me, it's very difficult. And there's no chance to do an edge quench because it's just not possible when the blade is double edged. So, you have to get both edges up to quenching temp or non-magnetic and then plunge the entire blade into your quenching medium. That's the only way I know of to get quench lines on a dagger blade. On a short one it's no problem, depending on the thickness of the blade and it's ability to hold the temp. On a longer one like the one in the pic, it's a real challenge.
 
I FINALLY understand the entire "Etch Process". you guys are great........Ira:) :D :) :)
 
Ok Ira, maybe you can explain it to me over a couple of beers when you come to visit. I still don't fully understand the process but I sure do have fun :D
 
I was shooting (no pun Max, how's the hand?)for the end of THIS Month, but that does not look like it's going to happen. But MARCH, NO MATTER WHAT, I am there, and intend on being a dutiful student and finally learn EXACTLY what goes into "making" a knife.

For the last 26 years I have collected firearms with a passion. There are very few firearms that I cannot talk about at any level, to include the "manufacturing process". Now, knives come into my life and I develop a PASSION for them at a level I NEVER knew existed, and have never felt when guns were the Number 1 hobby.

YET I remain totally and completely in the dark in regards to the "hows", the "whys", the "whats", and remain very, VERY CONFUSED about why carbon alloy steels differ from cobalt alloy steels, what goes into making a knife, and I don't even have a clue what types of equipment you guys use in your "work shop".

IT IS TIME I learn!!!! See ya in March Max!!!!;) ;) :) :D
Ira
 
Here I go stealing from another thread again. I felt that this post by Rex was pertinent to this topic.

First to answer some questions. Etching the blade will not ruin it for a knife. It is a surface condition only. The steel will be VERY prone to rusting, sometimes in only an hour or two if humditiy is high.
The muratic acid should be mixed 50:50 with water. If the solution is a little weak it will take a little longer to etch.Straight acid does not etch very well. It works better with water Old solution does not give as clean an etch as fresh and does not show structure as well. If you leave the sample in the acid too long it will have a dark burnt appearance.
Pressing and hammering will leave different properties in the steel.
Note that there is a lot of overlap but GENERALLY a press is more powerful and slower than a hammer.A press will move material both longitudinally and transversly{It squashes things}, A hammer moves less material per cycle but the force is more directed. Yhe sharp rapid blow of a hammer will tend to breakup inclusions and refine the grain more than a press will. Different dies can be used to help direct the metal flow. The BAUSCHSINGER EFFECT is really a kind of red-herring . It mainly manifests itself in material that has been cold worked . In oil country tubes its most notable after a tube has been heattreated and then needs run through a straightening process. At this point it is given a quick stress relief in a furnace . A complete heattreat will almost always prevent this phenomenon from occuring.
Rex
Click to expand...

I notice we have been doing a good job of butchering the spelling of the Bauschsinger Effect.
 
When Rex mentions the steel being very prone to rust, he is reffereing to blades etched in hydrochloric acid. Blades etched in ferrichloride are not as prone to rust as those etched in hydrochloric acid.
 
Everybody probably already knows this little secret. But, just in case I thought I'd share it. When etching damascus or forge finished blades I like to leave the grey oxidation in the inset or etched parts. It hilights the etch and gives the blade good visual relief. The best way I've found to do that is to immediately neutralize the ferric chloride by washing the blade with a stiff brush and baking soda mixed with liquid dishwashing soap. Scrub it down real good and get it nice and clean (the hard oxides will stay put). Then buff or hand sand (I use 2,000 grit wet or dry paper) the blade lightly to bring a semi-polish to the raised areas and clean the oxidation off. Wash again with dish soap and scrub brush.

Then, mix up a baking soda solution in a baking dish using 2 tablespoons per quart of water. Mix up enough to cover the blade and have at least an inch above it. Boil the blade (this won't effect the heat treat because it's only 212 degrees F) for at least 10 minutes but 20 is better. In order to keep the blade from contacting the baking dish during boiling I usually prop the blade up by the tip on the side of the pan. Just enough to keep it from touching the pan but still stay submerged. Use your imagination.

After boiling the blade remove it from the baking pan and let it dry on a paper towel. You will notice that it doesn't rust like it normally would. I'm not sure what the baking soda does to the steel but it gives it some form of rust protection. At least until you get it oiled down with your favorite oil (I use Ballistol). The grey oxidation is 'fixed' to the etched areas of the blade and is permanent as best I can tell. And the oxidation has another benefit as well. It holds the oil to prevent corrosion.

Give it a try if you haven't tried it yet and see for yourself. I've had very good luck with that process. It definately makes a difference. Maybe Rex knows something about the baking soda and how it has a rust preventative property when used this way. I sure don't. All I know is that it works.
 
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