Discoloration and Loss of a Wootz Pattern
 

I have several wootz blades which exhibit some discoloration/random white spots. Some of these spots are of circular shape, which suggests the "damage" could have been caused by a high speed polishing machine. Another suggestion is that they occurred naturally during forging. And yet another suggestion is that the blades were exposed to fire after forging. All these can cause reduction of the wootz pattern. I suspect is has been polished on the machine, which is known to cause loss and distortion of pattern.
Any other opinions, and have you seen similar distortions on other wootz blades?

Hi Alex, I have a tulwar that shows a similar sign on the blade, but no wootz and it was clearer after a light etching :confused:

Here is an example of a light area in wootz.

I think there are a couple of things that can cause "white spots" in wootz. I think the primary reason is a lack of heat control either during forging or heat treatment of an edge or tip. The other I have noticed can be induced from scabbard wear. A poorly fitted scabbard or one that has shrunk over time can certainly rub on singular spots on the blade and rub away the polish. However, in this case, you can usually still see the pattern beneath the rub spot if angled properly in the light. Certainly any grinders or other equipment used on a wootz blade can overheat the blade and disrupt the pattern as well.

I think you're on the right track with this train of thought, Rick . :)

also..
- could be a difference in metal ... martensite will etch dark.. and pearlite is much lighter... ... some times an air jacket will insulate the blade in spots, when you quench it..

- blade wasn't properly degreased before etch... and it protected the blade abit from the acid...... ( smudged finger prints or oils etc )

- a light layer of decarb... left over from forge process.... it will etch very lite and show next to no pattern... or non at all

- burnishing... restoring a blade an using high grit sand paper.... that becomes loded up with steel filings.... this will basically be using steel on steel and burnishing... this does reduce the pattern.... and can be localized...

-sometimes an exta dunk in the etch tank will get rid of this ... as it maybe just some water on the blade that momentarily delays the etch...

looks simple...but lots of things can cause this...

G