I wouldn’t personally blue a Damascus knife, however I have used commercial blue on high carbon knives and it has added some rust protection a substantial amount more protection I should say than an untreated HC blade.
I wouldn’t personally blue a Damascus knife, however I have used commercial blue on high carbon knives and it has added some rust protection a substantial amount more protection I should say than an untreated HC blade.
It provides limited corrosion protection. I would suggest just putting oil on it; more corrosion protection and it will not obscure the surface pattern which is most all that separates Damascus steel from ordinary steels. As I remember regular "bluing" is a complex of ferocyanides ; Oxides of iron are red and black , brown rusts are hydrated oxides. I have now looked at Wiki and see some of the problem. Molten cyanide salts are use to carbonitride steels;I believe these leave a blue surface- you can't do that. Another source of blue ( and straw and purple) color is different thicknesses of very thin oxide layers. I have a chart showing one hour at 540 F (in air) , or 10 minutes at 590 F, or 20 hours at 485 F will produce a blue. Higher temperature and longer time give thicker oxide. The color of the oxide is determined by the thickness. Assuming the blade is hard like Rockwell C 60, these temperatures will cause some softening. The other methods sound like they will etch the steel . Same conclusion, oil it.
It provides limited corrosion protection. I would suggest just putting oil on it; more corrosion protection and it will not obscure the surface pattern which is most all that separates Damascus steel from ordinary steels. As I remember regular "bluing" is a complex of ferocyanides ; Oxides of iron are red and black , brown rusts are hydrated oxides. I have now looked at Wiki and see some of the problem. Molten cyanide salts are use to carbonitride steels;I believe these leave a blue surface- you can't do that. Another source of blue ( and straw and purple) color is different thicknesses of very thin oxide layers. I have a chart showing one hour at 540 F (in air) , or 10 minutes at 590 F, or 20 hours at 485 F will produce a blue. Higher temperature and longer time give thicker oxide. The color of the oxide is determined by the thickness. Assuming the blade is hard like Rockwell C 60, these temperatures will cause some softening. The other methods sound like they will etch the steel . Same conclusion, oil it.
I wouldn’t personally blue a Damascus knife, however I have used commercial blue on high carbon knives and it has added some rust protection a substantial amount more protection I should say than an untreated HC blade.
I wouldn’t personally blue a Damascus knife, however I have used commercial blue on high carbon knives and it has added some rust protection a substantial amount more protection I should say than an untreated HC blade.
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It provides limited corrosion protection. I would suggest just putting oil on it; more corrosion protection and it will not obscure the surface pattern which is most all that separates Damascus steel from ordinary steels. As I remember regular "bluing" is a complex of ferocyanides ; Oxides of iron are red and black , brown rusts are hydrated oxides. I have now looked at Wiki and see some of the problem. Molten cyanide salts are use to carbonitride steels;I believe these leave a blue surface- you can't do that. Another source of blue ( and straw and purple) color is different thicknesses of very thin oxide layers. I have a chart showing one hour at 540 F (in air) , or 10 minutes at 590 F, or 20 hours at 485 F will produce a blue. Higher temperature and longer time give thicker oxide. The color of the oxide is determined by the thickness. Assuming the blade is hard like Rockwell C 60, these temperatures will cause some softening. The other methods sound like they will etch the steel . Same conclusion, oil it.
It provides limited corrosion protection. I would suggest just putting oil on it; more corrosion protection and it will not obscure the surface pattern which is most all that separates Damascus steel from ordinary steels. As I remember regular "bluing" is a complex of ferocyanides ; Oxides of iron are red and black , brown rusts are hydrated oxides. I have now looked at Wiki and see some of the problem. Molten cyanide salts are use to carbonitride steels;I believe these leave a blue surface- you can't do that. Another source of blue ( and straw and purple) color is different thicknesses of very thin oxide layers. I have a chart showing one hour at 540 F (in air) , or 10 minutes at 590 F, or 20 hours at 485 F will produce a blue. Higher temperature and longer time give thicker oxide. The color of the oxide is determined by the thickness. Assuming the blade is hard like Rockwell C 60, these temperatures will cause some softening. The other methods sound like they will etch the steel . Same conclusion, oil it.
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