Issue with heat-treat's effect on etching Damascus.

J

jwhoward73

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Sep 19, 2022
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17
Hello all. So, I ran across an issue with Damascus I hadn't before and am wondering if there is a way to fix my mistake.
I have a small mini-forge and it isn't deep enough for me to bring an entire 8 1/2" blade up to temperature before quenching.
As you can see by the coloration in my metal (pic attached after forge), after heat treating there is an obvious difference between temperatures the blade was brought up to.
After tempering twice at 400F. I evenly sanded all surfaces back to 600 grit before etching in FC. Now you can see there is a difference from a black to gray right around the line where the steel was heated to proper temp and where it was not. (pic attached after etching, another pic after etching)
This wouldn't be as big of a problem if the handle covered the entire tang, but, because of my design (pic attached shows layout of handle and exposed metal) and using antler for handles I am purposely exposing the metal at the upper part of the flat/recasso below the jimping, also, the part of the tang between the index finger and other fingers, and again behind the last 4 fingers.
My questions to someone with more experience than I are:

Do I try to heat treat again focusing on the handle part of the steel?
Do I try to flat grind the surface of the blade and try etching again?
do I just live with what I have?

Thanks so much for your time.
Jason

Pics below:
after forge
after etching
another pic after etching
shows layout of handle and exposed metal
 
Last edited:
Several things change the look of the etch. One is if the steel is hardened martensite or unhardened pearlite. Another is decarb on the surface. Pearlite and decarb etch gray.
Another thing that can affect the hardening is insufficient quenchant. You want the tank to be at least 4" wider than the blade width, and 4" deeper than the blade length.

You can "pump" a long blade through the forge (assuming it has a back opening) and heat a longer blade. I regularly HT a sword in a 16" three burner forge. Slowly push it through the back opening until the end of the tang is at the center of the forge and then draw it back until the tip is at the center. Keep doing this until you heat the entire blade to an even red color, and it becomes non-magnetic. Once it reaches the desired temperature, quench in plenty of quenchant. Practice on a 12"X1"X.125" bar of welding steel to get the speed and method down.
 
Stacy E. Apelt - Bladesmith said:
Several things change the look of the etch. One is if the steel is hardened martensite or unhardened pearlite. Another is decarb on the surface. Pearlite and decarb etch gray.
Another thing that can affect the hardening is insufficient quenchant. You want the tank to be at least 4" wider than the blade width, and 4" deeper than the blade length.

You can "pump" a long blade through the forge (assuming it has a back opening) and heat a longer blade. I regularly HT a sword in a 16" three burner forge. Slowly push it through the back opening until the end of the tang is at the center of the forge and then draw it back until the tip is at the center. Keep doing this until you heat the entire blade to an even red color, and it becomes non-magnetic. Once it reaches the desired temperature, quench in plenty of quenchant. Practice on a 12"X1"X.125" bar of welding steel to get the speed and method down.
Click to expand...
Good point, about moving the blade all the way through the back of my forge. I just need to open up the brick in the back. Im convinced that the cause of the etch being gray is because I didn't do a consistent heat treat for the full length of the blades. The front half of the blade looks fine.

Do you think I should try to re- heat treat? Ive never done that.... Would I just focus on heating up the portion of the blade that wasn't brought up to the appropriate temperature with my first heat treat?, or do the entire blade again?
Also, would I sand off the results of the initial etching before I heat treat again?
 
Thanks Stacy, that makes sense.
Would I just focus on heating up the portion of the blade that wasn't brought up to the appropriate temperature with my first heat treat?, or do the entire blade again?
Also, would I sand off the results of the initial etching before I heat treat again?
 
Heat the tang first using Stacy's pump method. When it approaches the color you are looking for, flip and heat blade.
 
Yes, work the tang part more in the pumps at first and then when it gets red pay more attention to the tip and main blade. The trick is to avoid overheating the tip. If done right the whole blade will be at an even color. Also, rotate the blade while pumping every now and then to evenly heat both sides.
 
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