Etching wootz, opinion needed.

Richard Furrer · 12th February 2020, 08:07 PM

Just saw the thread.

Coffee etch is the latest rage in knifemaking. Before that it was "baked on brown or black lacquer".
I find ferric to be as good as one gets on wootz and some old wootz etches better than others. Some prefer nitric. Both used in very dilute forms.
Some come away very black with ferric and others whiteish. I assume it is slight internal chemistries which cause the coloration variables. Heat treatment does play a part as well and the cause of most etching coloration issues within a single bar as with the blades shown above in the thread.

I have not found the carbides to go away till high into the bright orange colors when forging and even then you can bring them back if you further play with heat. As we have all seen the weld joints on Indian blades show a black weld line and white on either side and then pattern as we expect. I promise you that those have reached a full welding temp when they are made....or repaired...the jury is still out on why they have those welds...the record I have seen was a Tulwar in Jodhpur, India with three welds...meaning four pieces.

I will shortly begin a project which will have several wootz welds. No need to post it here as it is modern material all around.

Ric

12th February 2020, 08:07 PM	#13
Richard Furrer Member Join Date: Mar 2006 Location: Sturgeon Bay, Wisconsin Posts: 163	Just saw the thread. Coffee etch is the latest rage in knifemaking. Before that it was "baked on brown or black lacquer". I find ferric to be as good as one gets on wootz and some old wootz etches better than others. Some prefer nitric. Both used in very dilute forms. Some come away very black with ferric and others whiteish. I assume it is slight internal chemistries which cause the coloration variables. Heat treatment does play a part as well and the cause of most etching coloration issues within a single bar as with the blades shown above in the thread. I have not found the carbides to go away till high into the bright orange colors when forging and even then you can bring them back if you further play with heat. As we have all seen the weld joints on Indian blades show a black weld line and white on either side and then pattern as we expect. I promise you that those have reached a full welding temp when they are made....or repaired...the jury is still out on why they have those welds...the record I have seen was a Tulwar in Jodhpur, India with three welds...meaning four pieces. I will shortly begin a project which will have several wootz welds. No need to post it here as it is modern material all around. Ric