how to remove a high polish finish

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wolverine_173

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i want to remove a high polish finish from a knife,

how do i do it. i want a darker patina. can i just use an acid
 
If that knife is what I think it is, which is 1095, or any simple carbon steel, you can use many different things. If you are looking for a patina, I have had good luck with mustard, A1 steak sauce, and also vinegar. Any of those will patina carbon steel. I think mustard is the easiest to work with. You simply coat the knife in a nice, even coating and let it sit for about 30 minutes. Then you can wash it off and assess. If you're happy then good, if not you can do it again.

Hope this helps.
 
wolverine_173 said:
its the 5160 steel

So the polish wont impede the patina
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wolverine_173 said:
Huh. I just want it to look stripped not shinny
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One way to do it, is to dip the blade in a mix of hot water & vinegar. I've done this with high-polished CV blades from Case. Ordinarily, a polished finish would slow patination somewhat, if attempted by other means; but the heated mix will speed things up considerably. I did mine with the water/vinegar mix used to de-scale my coffee maker (two birds with one stone; it was convenient). The heated mix was at ~168°F as it was dripped into the pot (I measured this); I used a 50/50 mix. When the mix had finished filling the pot, I just dipped my blades into it, and watched the patina form in front of my eyes. Only took a few minutes per blade, and I was periodically lifting the blade out of the liquid to check progress (though it's possible to see a lot while it's immersed). The steel literally darkens as you watch, and you'll likely see bubbles coming off the steel as it works. When it was as dark as I'd like, I rinsed the blade in clean running water, and also scrubbed it with some baking soda to neutralize any acid left. The baking soda will scrub some of the really BLACK & loosely-bound oxide off, and any red rust that may form in the process, leaving a fairly even grey patina behind (maybe darker, depending on the steel).

Make sure the blade is very clean & dry before starting; any oils or grease (fingerprints, etc.) on the blade will interfere with an even patina. Wiping the blade with some isopropyl alcohol will strip any of the oils/grease away. Might also remove the handles if it's possible; that'll make dipping the blade that much easier.

If, for some reason, you don't like the look of the patina, you can still polish it off with some polishing paste like Flitz/Simichrome. Doing it this way will avoid any scratching that would happen, if trying to alter the finish by sanding it. There are lots of different ways to go about it, but the above method works pretty well, and is pretty easy to work with.


David
 
Seems like he wants a brushed finished rather than any patina?

To get an even brushed look id imagine you'd need a cloth wheel for a drill or grinder and a course polishing compound of some kind.

Or even better, take it to professional metal polishing/chroming place and get them to do it.
 
skippy75 said:
Seems like he wants a brushed finished rather than any patina?

To get an even brushed look id imagine you'd need a cloth wheel for a drill or grinder and a course polishing compound of some kind.

Or even better, take it to professional metal polishing/chroming place and get them to do it.
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From the OP (@ bottom of his post):

"how do i do it. i want a darker patina. can i just use an acid"
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I had a decently polished knife in L6 (idiot me polished my Svord Peasant not aware that L6 rusts from sunlight, apparently), and I put a patina on it over 2 nights by wrapping it in a paper towel then soaking it in rice wine vinegar, then doing the same the following night with balsamic vinegar. Gave it a really cool random pattern 2 tone finish and the previous polish was totally gone. You could even go a step further and soak it a third night with apple cider vinegar for a third tone.
 
I work in a polishing shop and use Scotch brite all the time for this o purpose, it would be the easiest option, just try to get your lines as straight as possible, depending what kind of scotch brite you can find, any will work we use all 3m I believe. I'd recommend what we call "maroon" just because that's what color it is, it's medium if you can find it (there are a ton of different kinds, darker is generally coarser and light colors are finer usually). But the easiest and cheapest route would be to raid the kitchen look for any kind of brite preferably a new piece, and even brillow pads will work. Whatever you do use wd40 to lube it, will give you softer lines and not so inconsistent. Good luck!
 
this is what im going for


So all i need to know if I can still do it with mustard or vinegar even though its polished up so much.
 
Whether or not the surface is polished will have nothing to do w/ its ability to oxidize
 
How would you explain that aus 8 pits and rusts so easily when bead blasted if surface finish had no influence on corrosion...?
 
wolverine_173 said:
this is what im going for


So all i need to know if I can still do it with mustard or vinegar even though its polished up so much.
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Yes, you can. Whichever method you use (mustard, vinegar, combination of the two, etc.) will affect how it looks in the end. Almost infinite possibilities in how it'll turn out. The 'dipping' method I mentioned earlier generally leaves a more even patina. The mustard method is often used to apply unique patterns, if you want to do that, by spreading or applying mustard accordingly.

The high polish, as I mentioned earlier, will tend to resist oxidation a little bit (this is how a polished finish can help minimize rust as well), and therefore slow it down. It'll still oxidize though, and a 'hot' application accelerates it. If you want to, you could scuff up the polish before starting, using some Scotch-Brite or medium/high-grit sandpaper. The rougher finish tends to give more surface area for oxide to form, and therefore will speed it up and/or leave a somewhat darker or flatter (less glossy) finish. If you're still wanting an even-looking finish, it's very important to make sure the scuff/sanding pattern is very uniform; if it isn't, you'll likely get blotchy results.

Nice thing is, if you don't like how the final result looks, it can all be polished off with some Flitz or Simichrome paste and some elbow grease, and you can start over if you want to. Not that much risk in experimenting, within reason, assuming more harsh acids/etchants aren't used (ferric chloride, for example).


David
 
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