Removing temper line ?

[Alain M-D]

I finish my first knife yesterday ! But after I polished
them to a mirror finish, the temper line are still visible..
How I can make to hide this temper line ?

My small blade (6" overall) is made in O-1 steel and I used canola oil for my heat treating.

My second interrogation is: when I dip my non-magetic blade into the warm oil, I was really surprised because I not see fire or smoke when I dip the blade into oil... Even not a psshhh...
This is normal?

 

[Chiro75]

Wow, I've never heard of anyone who wanted to *hide* a temper line! Why do want to get rid of it? Anyway, as far as I know, you can't really get rid of a temper line altogether unless you coat the blade. The temper line is created because there is a difference in the crystalline structure of the steel in the hardened part versus the soft part. It is inherent to a blade heat treated this way, so you can't get rid of it. Etching the blade obviously makes it really stand out, but in the right light, and with a little use and oxidation, you will still always see the temper line a bit. The finer you sand the blade, too, the more the temper line will stand out, so you will want to rough sand it, bead or sand blast would work, etc.

As far as the oil goes, I've never lit it on fire, either. The oil should be warm before quenching a blade, too. If you're worried about the hardness of the blade, check it with a file. If you hardened it enough, the file will skate off the edge rather than biting in.

 

[peter nap]

That's like Barb Wire wanting to hide her chest! Your a sick man!

 

[richard rosvall]

I agree with Steve and Peter. Not sure why you would want to remove the temper line. Many folks strive to achieve it. It's positive proof of a well-done heat treating job.
Also, I've never had oil flame up on me. Sounds like a normal reaction for a small knife.

 

[blackboogers]

Rub with 600 silicon carbide paper and most of it will go away,sand in one direction. A good using knife finish.

 

[Dan Gray]

Paint it with cheap black paint.
then when you show it to another maker
explain why you want to hide the temper line??
your setting knife making back 100 years man

 

[helmar4578]

The easiest way to hide a temper line is to keep the knife in a sheath! Sandy

 

[Taz]

bead blasting or sandblasting will not remove the temper line. The hard steel blasts at a diff rate than the softer steel, and the hard steel is usually darker IIRC.

Re heat treating the knife and doing a full HT instead of one showing a temper line one of the few ways to get rid of it.

 

[Alain M-D]

It is not that I do not like to see the temper line, but rather than because of it, my mirror finish is not perfect. It is good on the cutting edge side (1/3 or 1/2 hard part of the blade) but appear more greyish on the top (soft spline)...

It is possible to put a mirror finish on a knife with a selective heat treating (only on the 1/3 of the blade ) ?

 

[Dan Gray]

Sure it's possible.
I grind like this for the a hollow grind.
for belts
I use
80 grit for roughing down to size.
220 grit for clean up and sizing.
30 micron
to remove the 220 scratches them to a 30 micron
then I do my heat treat,
then back to the.

(It's important that you go over it again to
remove the burnt steel,the layer of
de-carbonized steel, it will not take a good polish.)

220 grit then the 30 micron again
then 15 micron. to remove the 30 scratches
then hand sand with 1000 - 1200 grit A/O
wet or dry paper.
you can go up to 1500 or 2000 grit if you want..
then buff lightly with white rouge..
Now this works well for the way I heat
treat and temper.
I hope this helps