SOG Pentagon Stained Blade?

Havoc550

Havoc550

Joined
Oct 9, 2011
Messages
758
I just received this SOG and am a little upset. The blade just looked dirty so I gave it a quick rubdown with some choji oil. Other than some of the grime wiping away, I could now see apparent stains. I tried some noxon, which is a non-abrasive metal polish and still, nothing.

On this pic, you can you can see a strange haze over most of the blade. The dark spots in the center right are actually clean steel.

6d50R.jpg


The back actually looks fine, however you can see the same stain/haze on the lower edge and around the serrations.

k5O9c.jpg


Am I going to have to resort to more "abrasive measures"? Since this knife isn't exactly mint, the tip has a tiny ding, it will probably get some use and not be a shelf queen. However, I do not plan to abuse it.
 
Use some Simichrome or Flitz. Non-abrasive polishes generally won't help much at all, if they truly are non-abrasive. Abrasive is perfectly OK, as the particle size is so very small. The abrasiveness is what gets the real work done, and what actually polishes hardened steel. Don't worry, it won't hurt that blade at all.

I'm betting a 'non-abrasive' polish is more likely intended for fine jewelry, like plated gold/silver/etc. Abrasives will harm those, by stripping the very thin plating off. Solid, hardened steel, on the other hand, won't be harmed at all by an 'abrasive' polish.
 
I just looked at an MSDS for 'Noxon' polish. It relies on 'crystalline silica' (abrasive, but a relatively mild one; it's what sand & glass are made of) and oxalic acid (good rust/oxide/tarnish remover, if using on carbon steel, brass, silver, etc.) to do most of the polishing/cleaning work. Silica is usually too soft to affect stainless alloys (such as the AUS-8 in your blade), and it's also what's commonly used as the 'mild abrasive' in toothpaste. And the oxalic acid won't really do much to it either, as it's intended to dissolve rust and other metal oxides, which really aren't an issue with stainless steel anyway.

Polishes made especially for hardened steel usually use very fine aluminum oxide as the abrasive, which is much harder than silica, and therefore much more effective for polishing steel. Simichrome and Flitz are examples of these.
 
Thanks for the responses!! Noxon was the only polish recommended for medium to high end swords such as forged katanas and antiques. Its what I usually use if I need to correct a spot on a sword, so I figured I would try it on this knife.

I did find an old can of Wright's Silver Cream. It didn't work either and further research shows it to be pretty mild as well. I guess I will be buying some better stuff tomorrow.

On a good note, I was able to work the bent tip out that I didn't mention earlier. I see a lot of knives, especially daggers that have the very last half a millimeter of the tip bent. Looks brand new now minus the stains which I hope to get out tomorrow.
 
I haven't had a chance to pick up some better metal cleaner, but I wonder if anyone can tell me if those stains were caused by tannic acid? The knife was stored in its sheath by the previous owner for many years. I noticed my original Cold Steel Magnum Tanto has a very similar haze , although not nearly as bad. It too has been stored in its sheath.

If it is indeed caused by tannic acid, can it still be removed?
 
There might've been some reaction there, with acids in the leather. If so, those black stains are likely just 'black oxide' (what would be called 'patina' on a non-stainless blade). BUT, even so, Flitz/Simichrome should take care of it easily. Assuming there wasn't any pitting or real corrosion, which would need sanding. But I don't think that's an issue, based on your pics & description.
 
Nope, no pitting and no rust marks at all. The woman is out shopping right now while I clean up all my messes at home. There are knives and RC parts everywhere as I re-organize and sell some of my toys. Only RC stuff gets sold, the knives are staying.

She is picking up one or both of those polishers so I should have it looking good soon. I was concerned about the tannic acid because a few websites said it could permanently ruin a blade and could not be removed. I found that hare to believe, but I figured I would ask.

Hopefully I will have this bad boy cleaned up today and ready for a few pics. Thanks!!
 
No Flitz or Simichrome anywhere!! I had to settle for Brasso today and guess what.....NOTHING!! I rubbed the hell out of the blade and nothing changed. I have used Brasso and Simichrome in the past, when I saw a picture of the tube I remembered it. I have seen black stuff come off of even the cleanest of metal with both polishes. The Brasso I used today produced nothing, I don't get it. Maybe I should leave the stain alone, whatever this is, it's protecting the blade from me!! :)

I have repaired a few blades in the last week. One in particular was old Smoky Mountain Toothpick by Parker Brothers. The blade edge was dinged up, the finish was scratched to hell and back, etc. I worked all the nicks out, gave the knife a new edge and used a green scotch-brite pad to fix the finish. The knife looks brand new minus the dings in the handle. Point being, I do not want to have to resort to the scotch-brite pad on the pentagon. Given what appears to be a complex grain pattern, it may look horrible when I finish. All those old Parker Brothers knives have a straight, top to bottom scotch-brite finish to begin with, so I was able to make the knife look brand new. Scotch-brite also works great on turning a mirror sharpened edge into a satin one. I am not a mirror finish guy.

I ordered some simichrome and flitz from Amazon today. I will try both before I make any decisions on what to do next.
 
Brasso is similar to the 'Noxon' polish, at least from an abrasive standpoint. As the name might imply, it was made for brass and other relatively soft metals. I've attempted to use it myself, on knife blades, as a stropping compound. Largely ineffective for that too, at least with more modern steels (like stainless alloys). Just not hard enough to polish steel effectively.

Take a deep breath, relax and wait for your Simichrome & Flitz to arrive. I'm sure either one will take care of this.
 
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