Polishing Ti liners back to "silver" color

J

jcrim007

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Sep 4, 2003
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** Custom Benchmade Question **

as some of you know, i just got my first benchmade, an 880S dark star.

as some of you know, this knife has gold-toned titanium liners to it... but i am not too found of gold, just thought the knife was too good to pass up.

as with my pistols, i am a custom nut, and would love to have these liners a "silver" color

can i get some tips, from the experts, on how to polish these Ti liners?

thanks
 
They won't stay really silver forever. Ti is corrosion resistant because it forms an oxide layer on the surface. The oxide is sort of a light brown/silver. The gold color is a colored compound that is also resistant to corrosion so it won't change. Actually what you're trying to do probably will work (assuming you can remove the gold, and I don't really have experience there, I would guess you could scrub it off with something abrasive and then polish). Once polished, It will turn slightly brown as it meets oxidizers, but not so much that you probably couldn't keep polishing it. If it was me, I'd let the natural patina (oxide layer) build-up.
 
"The gold color is a colored compound"

Unless Bm is doing something really funny, that is not the case. It is simply anodized to a very low voltage (gold can be hit at about 10-12volts).

Ti Oxide is acually perfectly clear, not the brownish silver. Unlike Al, you do not physically add color to Ti. When anodizing titanium you are building up a clear layer of ti oxide. This layer filters the light entering and bouncing off its surface. Depending upon how thick the layer is determines what colors are filtered and therefore what colors we see.

After time ti will indeed build its own very thin layer of oxides. What you are seeing in the silver/brown, is the very beginings of "straw" which is the first color produced in anodizing (5-8 volts).

Kind of symantics but it is important to understand.

As to removing it. You can do it yourself pretty simply. Take the knife fully apart and use a fine scotchbrite pad (Home Depot paint dep.) By taking your time and gently rubbing the liners you will wear off the anodizing.

Another option is this. Since the gold is so low on the voltage scale, you could have them anodized pretty much any other color to suit you wishes. There is one problem however. There are two golds on the voltage charts, one at around 10v and one at around 50v. The only differance is the 50v gold is a little brighter. If it is the 50v gold your color choices would be slightly less, but not by much. You would lose some of the lighter blues, bronze/copper and the bright purple.

As for the actual anodizing. If you decide to go that route there are many forumites with the gear to do it. I anodize pretty much every day and would be happy to zap up a color for you if you wish. Just send me a line. I would want the knife fully taken apart first though. I also have the ability to chemically strip the anodizing. I only fire this solution up about every two weeks so it would be a longer turn around.
 
OK I see what you are saying in that the oxide itself is clear. I didn't actually know that part of it before. Very interesting. I knew that anodizing was depositing oxides which cause the colors, but I wasn't aware of the mechanism.

The colors produced by Titanium are known as interference colors. There are no pigments, dies, or chemicals involved. The colors are generated by a thin transparent oxide film on the metal surface. Titanium can be anodized by heat, or electric anodized. By passing a current through the titanium, the metal reacts, and creates interference colors. Every color in the rainbow can be achieved by this effect. The colors develop when part of the light striking the surface reflects and part pass through the film to reflect off the metal below. When the delayed light reappears and combines with the surface light waves they may either reinforce or cancel. This generates a specific color. The thickness of the oxide film dictates the color. In nature these colors can be found in the iridescent colors of some insects, and the colors produced by oil on water.
Click to expand...
http://www.argusdesigns.com/products/titanium/ab_titan.html

Titanium does indeed turn a nice silver/brown in very corrosive environments when left "natural". I have seen much of it as chemical process vessels, pumps, airplane hydraulic lines etc. I'm a Chemical Engineer. The slight brown tinge is how we can tell it apart from stainless in the field.
 
wow. thanks for all the input everyone.

about the Bm warranty... i know doing this will void their warranty on the knife... so, do you think they would do this for me? so i could keep warranty. or do they not do custom work?

thanks for the offer R.W., might take you up on it :D (if Bm can't come thru)
 
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