52100/etch shows I failed my heat treating...

[DaQo'tah Forge]

hi this is DaQo'tah

when last I wrote about my attempt to make my very first knife, I talked about the trouble I was haveing with the heat treating.

well the 1st heat treating went bad,,,but I sure thought the last 2 went just like the book says.

But today I etched the blade, and soon learned that something went wrong.

1st Im trying to copy the Ed Fowler 52100 video, and in the video Ed says to mix the etch stuff "2 to 1"...I took that to mean two parts water to one part etch?...well, thats too weak for my blade, so I ended up pouring some out and then dumping the whole etch stuff into my jar that I had the blade sitting in.

after 10 min, I lifted the knife hopeing to see the sign of a good heat treating,,,,there was none,,,,10 more mins later I still didnt see any sign of a heat treating, but I took the blade out of the etch and placed it into the TSP jar,,,an odd thing happend next.

the water of the TSP jar became filled with,,,gunk?

Stuff (from I dont know where) suddenly started to swim around in the TSP jar.

I washed off the knife, and then did as the Fowler video shows and buffed the blade.

Now I can see clearly that I really messed up my heat treating,,I dont even have much of a line to see on the blade at all. there is a line, about 1/4 inch wide, and it goes up the blade edge a bit,,,hit and miss...then fades away near the tip.

I must not have heated the blade hot enough?

is there anything I can do now to fix it?
I wish to learn how to make a brass guard next,,,so Im not going to toss away this knife,,,But I would love to hear any ideas on how I can fix my bad heat treating?

can I just heat it up one more time, now after its so thin and sharp?

Please anyone help me fix this!
any advice, I will try anything, ...

 

[burke531]

Just heat it up and do it again. This time make sure to check the steel with a magnet and make sure that the blade is nonmagnetic before you quench the blade. Did you check the blade and make sure that it was hard after you hardened it the first time? Do this to. Also check the spine of your blade and see if it is hard. If the blade is hard all over then you wouldn't get a temper line on it.

 

[Kisu]

There is the possibility that your heat treat isn't bad. Using etchant at full strength will etch the hardened and non-hardened areas almost equally. The ratio of 2:1 (2 water 1 etchant) should be alright(a little strong for my tastes, I use 3:1) but you may have to leave it in for 10 mins at a time and do this more than once. Neutralize with baking soda between etches and drying completely is advised also. Before you chuck it, you should try the brass rod test. If it flexs and returns without breaking than that would be a sign of a good heat treat.

 

[Centaur]

Originally posted by DaQo'tah Forge
...but I took the blade out of the etch and placed it into the TSP jar,,,an odd thing happend next.

the water of the TSP jar became filled with,,,gunk?

Stuff (from I dont know where) suddenly started to swim around in the TSP jar...

If you didn't wash the blade off with water before you placed it in the TSP solution, you should expect some reaction between the FeCl and the TSP. Probably some violent foaming action. Try dropping a few small drops of straight FeCl into your TSP solution. You'll see what I mean. It's like pouring vinegar into a baking soda solution. Same reaction.

 

[Joss]

In any case, 52100 often benefits from multiple quenches, so re-quemching shouldn't hurt.

JD

 

[Guy Thomas]

You can try re-heat treating the blade but test it out first! Put a good sharp shaving edge on and chop through a 2x4 a couple of times and see how the edge holds up! And try the brass rod test like Kisu suggested. You need to analyze the results of these tests in conjunction with the process you employed in the heat treating and see how it holds up.

 

[DaQo'tah Forge]

was my etch too strong?...well,,I dont know,,,could be,,,but I mixed it at first 2 water to 1 etch, after 10 min there was no sign at all of any heat treating lines.

was there suppose to be?

oK, the next thing I did might sound a bit crazy, but I thought at the time that my etch mix was too weak,,,so I dumped out about 1/2 a cup of the mixed etch,,,then dumped the rest of the full power etch into the jar with my blade.

the blade was turned dark,,,it had some type a scale on it. then in the TSP it went wild,,,I had stuff swimming around ,? stuff almost looked alive...

what I might try tomorrow is to re-heat it,,But this means that i will likely burn steel cuz I have it already shaveing sharp. I will do the 2x4 cutting before i heat treat, it would be nice to know if it can do that.

Maybe I can heat treat it a 4th time, then etch it again.
(ok,,this dont sound to likely to work even to me, but its worth a try?)

 

[DaQo'tah Forge]

ok, one more thing before I do this again....tsp? ...bakeing soda?...water?

I was looking at different topics before this room lost the "search" setting, and I was reading a debate as to what to place the blade in when you take it out of the etch.

there was a disagrement as to the ues of TSP. some said that Etch was not an acid so many of the things people were useing were meaningless, that it was the washing under water that did the work to stop the etch.

I was thinking,,,,anyone remember what was the best advice for the after etch treatment?

 

[Will52100]

All I do to mine is spray with Windex, then wash in the sink with baking soda.

Not shure, but sounds like one of my first 52100 blades, I didn't get it hot enough, and the blade didn't harden. A file after quench will tell you a lot.

If it didnt' get hard I would grind a little off the edge profile to thicken it up a little, then re-quench. The way I do the quench is that as soon as part of the blade becomes non-magnetic I have a color to go by and forget about the magnet. When the color becomes even over the lower half of the blade I quench edge down. After quench the scale should be loose and you should see a hardoned zone where it was quenched. Check with a file, it should scate acrouse the hard and bite into the soft.

After clean up and temper, I dip the(cleaned with dishwashing liquid, 600grit finish) blade in a 4-5 parts water to 1 part ferric solution. the hard edge showes almost imedatly, but requirs a longer ecth to survive buffing.

To what grit was the blade finished? I have gotten spotty etches after only takeing to a 220 or so grit and not cleaning all finger prints off.

Hope this helps, and don't give up, I'm shure most knifemakers, me included, have a bucket full of screw-ups.

 

[DaQo'tah Forge]

this is DaQo'tah!!

The blade can still cut,,,I have to admit that this 52100 steel can really do the job. I cut a 2by4 in half darn fast!,,,and I next ran the blade on my arm,it still would shave hair too,,but the lack of a nice looking etch /temper line got me to do yet a 4th heat treating.

I hit the edge of the blade with the sander to "Blunt" it so as to kinda protect the steel inside from a loss of carbon.

I did a great heat treating this time,,,everything went like the Ed Fowler video teaches me.

I have a home-made tempering oil heater that brings the temp of the oil right up to Mr. Fowlers suggested 160 in no time at all and holds it there for as long as I need.

I made a little table in my oil tempering tank just like Ed Fowler talks about,,things are looking good,,I waite now for the blade to rest and cool, then I will buff it and etch it tonight to see if this 4th heat treating worked...