Nothing wrong with that cleaning result Jean, it is as Detlef has said, it was deeply corroded in the first place.
Actually, the material in that blade does not appear to be what I had in mind when I used the word "spongey".
Some Javanese blades have pamor sanak that has been made from what appears to be very low quality wrought iron that has not been cleaned properly during the forging process, when you try to clean it with anything, even my old-time favourite, pineapple juice, it develops holes and open grain that was simply not visible before the cleaning process.
Your blade shown here has a heap of pits, caused by corrosion, it does not display the effect I have tried to describe.
Incidentally, I think you will find that the heavier concentration of pitting in the front part of the blade has occurred where it has been heat treated, behind the point at which the heat treat stopped the pitting is less concentrated.
Note, the "cleaning during the forging process" that I mention above has nothing to do with vinegar, it is the repeated folding and welding of material in order to remove impurities. The general rule is that you fold and weld until "stars" do not fly from the material at weld heat when struck by the hammer.
|