Vinegar etching

Joined
Apr 9, 2016
Messages
8
Hello folks

Looking for some advice on etching a blade with vinegar. I am new at this and have ground several knives. None are heat treated yet. A couple are 440C and a couple others are made from a simmonds file and a nicholson as well. Is this the time to do it or should I wait for heat treat and temper? I dont even know what finish I'd be looking for. Just something out of the ordinary is pretty much all. Hoping some or at least one of you wouldn't mind imparting some wisdom my way. If your're feeling exceptionally generous then maybe you might share some thoughts on heat treating file steel at the same time? The 440C is not a problem in that department as I have done some of that steel with good results. Thanks in advance.

Kenadian
 
With vinegar I belive a forced patina is what you are trying to achieve. Etching requires electricity and other equipment. If you are trying for a forced patina it should be done as a final step once the knife is complete.
As far as heat treating the file knives, it's a crapshoot because of the unknown steel. That being said I have had good results making the assumption that Nicholson files are 1095 or very similar.
 
Consider having the 440-C bladed heat treated by Rob Riddley at Canadian Knife Maker Supply. He does super work. I don't see how you figure you know how to do it if you don't know how to do the files. He has lots of great knife making steel for sale.
Frank
 
Etching is a chemical process where the surface is oxidized and/or stripped off. Some is done with electric current, and some just by chemical action. The most common etchant for knives is Ferric Chloride. It reacts with the steel and darkens it. It also removes the steel slowly, as is needed in etching damascus. Many knife makers give a carbon steel blade a short FC etch to darken the blade. Use FC in a diluted state of about 3:1 up to 10:1 from the stock strength.

Stainless steel is not usually etched unless you want a satin "frosty" look. It doesn't darken by reacting with the acids - thus the name stainless. The etchants for stainless steel are usually strong acids like hydrochloric acid (Muriatic). These are not really good for beginners, and require careful use and storage.

Milder acids are used to quickly get the darkened patina on carbon steel that slowly forms with age. Mustard, ketchup, lemon juice, and vinegar are the usual things used. Lemon juice is citric acid, and vinegar is acetic acid (Ketchup and mustard have vinegar in them). Vinegar works best when warmed to about 100°F and allowed a long soak. It will not noticeably affect stainless steel. Plain white vinegar is what you want, but any vinegar will work.

Making a blade darken quickly is called a "Forced Patina". As with all patinas, it is only oxides on the surface, and will rub off in sanding and in use. One reason the "mustard finish" is popular is because it is blotchy, and thus doesn't show wear and variation as bad as a solid dark surface.

As alloys are added to steel, it changes the way it reacts to the acids. Once there is 12% chromium, it ois considered stainless. Varying amounts of chromium, nickel, and molybdenum will greatly affect the color of the etch as well as how rapidly the steel etches. This effect is used in making damascus steel to get the varied look of the etched surface. Plain carbon steel with little or no alloying will etch black. Others will etch grey, frosty, or little at all. Steels with low carbon etch less dark than steels with high carbon. This is used to great effect in making san-mai from a high carbon core and low carbon sides. One dip in the FC tank and the edge is black, while the sides are varied grey colors. This really shows up dramatically in san-mai with suminagashi sides.
 

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As per usual Stacy, you are a wealth of information and answered a few questions about etching various types of knives that I've had as well. Thank you.
 
With vinegar I belive a forced patina is what you are trying to achieve. Etching requires electricity and other equipment. If you are trying for a forced patina it should be done as a final step once the knife is complete.
As far as heat treating the file knives, it's a crapshoot because of the unknown steel. That being said I have had good results making the assumption that Nicholson files are 1095 or very similar.

Thanks very much. I will give that a try I inherited a large selection of old files some not worthy of filing anymore. Seems like they should get re-purposed rather than thrown onto the trash pile.
 
The one part of your question that didn't get answered: Etching/Forced Patina is a "Finish" which puts it at the last step of a knife. Grind the knife, get it heat treated, finish-ground, detailed, and THEN etch/patina. I have made a few carbon knives that people complained about rusting/staining. I took them back, sanded them clean and then did a mustard patina. They loved the new look and never complained again about the knife getting stained. (Because I gave it to them pre-stained).

As always, Stacy is spot on.

J-
 
Consider having the 440-C bladed heat treated by Rob Riddley at Canadian Knife Maker Supply. He does super work. I don't see how you figure you know how to do it if you don't know how to do the files. He has lots of great knife making steel for sale.
Frank

Thanks for taking the time to reply. I have done some other blades in 440c with a fellow who has been heat treating stainless for years so I am familiar with the process. I haven't done any file knives and have access to a means of heat treating them myself. Rather than waste my time or energy on something before I have a good idea I figured I would shoot the question out there. Anyway I would use Canadian Knife maker if I didn't have options closer to home without having to mail out my knives. Nice folks there bought my KMG knife grinder from them.
 
Etching is a chemical process where the surface is oxidized and/or stripped off. Some is done with electric current, and some just by chemical action. The most common etchant for knives is Ferric Chloride. It reacts with the steel and darkens it. It also removes the steel slowly, as is needed in etching damascus. Many knife makers give a carbon steel blade a short FC etch to darken the blade. Use FC in a diluted state of about 3:1 up to 10:1 from the stock strength.

Stainless steel is not usually etched unless you want a satin "frosty" look. It doesn't darken by reacting with the acids - thus the name stainless. The etchants for stainless steel are usually strong acids like hydrochloric acid (Muriatic). These are not really good for beginners, and require careful use and storage.

Milder acids are used to quickly get the darkened patina on carbon steel that slowly forms with age. Mustard, ketchup, lemon juice, and vinegar are the usual things used. Lemon juice is citric acid, and vinegar is acetic acid (Ketchup and mustard have vinegar in them). Vinegar works best when warmed to about 100°F and allowed a long soak. It will not noticeably affect stainless steel. Plain white vinegar is what you want, but any vinegar will work.

Making a blade darken quickly is called a "Forced Patina". As with all patinas, it is only oxides on the surface, and will rub off in sanding and in use. One reason the "mustard finish" is popular is because it is blotchy, and thus doesn't show wear and variation as bad as a solid dark surface.

As alloys are added to steel, it changes the way it reacts to the acids. Once there is 12% chromium, it ois considered stainless. Varying amounts of chromium, nickel, and molybdenum will greatly affect the color of the etch as well as how rapidly the steel etches. This effect is used in making damascus steel to get the varied look of the etched surface. Plain carbon steel with little or no alloying will etch black. Others will etch grey, frosty, or little at all. Steels with low carbon etch less dark than steels with high carbon. This is used to great effect in making san-mai from a high carbon core and low carbon sides. One dip in the FC tank and the edge is black, while the sides are varied grey colors. This really shows up dramatically in san-mai with suminagashi sides.

Thats awesome info. Nice looking work on those pics too. Definitely something different.
 
Thanks everyone for giving me your thoughts. Now its time to get to work and try some of this stuff out.
 
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