Off Topic Curious Maxamet Patina

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Just thought I'd share this picture of a forced patina on a factory Maxamet Native I'd seen on reddit. The circle around the spydie hole was not created intentionally and it appears centered on the hole. Any idea what could've done this in the production cycle?

5p3csasg4fe31.jpg
 
Huh, I never realized the holes were laser cut. I guess I always assumed they were drilled out.
 
Just thought I'd share this picture of a forced patina on a factory Maxamet Native I'd seen on reddit. The circle around the spydie hole was not created intentionally and it appears centered on the hole. Any idea what could've done this in the production cycle?

5p3csasg4fe31.jpg

Maybe somehow the blade’s heat treat got altered when the hole was cut? I assume they cut the holes pre-heat treat so maybe the steel was altered somehow at that point?

I would send this to Spyderco, it’s super interesting. @Sal Glesser any idea?
 
I would agree that there are different hardnesses on that blade. The area around the hole was probably tempered by residual heat that either the laser that cut it or the mill that ground it out generated, however they do it. I have a TOPS knife that I stripped and then forced a vinegar patina on. The knife is differentially heat treated and the harder area of the blade is very dark, almost black. The spine side and most of the primary bevel is more of a gun metal gray. The real test would be to find another maxamet bladed spyderco and do the same to it and see if the results are the same
 
Wow! Compared to that one, the blotchy looking, naturally obtained patina on mine looks great.
IMG_0686-X3.jpg
 
I'm not a knife maker & I'm not an expert on metallurgy, so maybe I'm wrong, but I call BS. I find it hard to believe that a difference in hardness, or heat treat would make the absence of patina come out so perfectly. It looks to me like a 1 3/8" rubber washer was centered on the Spydy hole & tightened down before the patina was forced. But like I said, I've been wrong before.

I'd like to see the other side.
 
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I'm not a knife maker & I'm not an expert on metallurgy, so maybe I'm wrong, but I call BS. I find it hard to believe that a difference in hardness, or heat treat would make the absence of patina come out so perfectly. It looks to me like a 1 3/8" rubber washer was centered on the Spydy hole & tightened down before the patina was forced. But like I said, I've been wrong before.

I'd like to see the other side.
I couldn't figure out how to share the reddit link on mobile, but there's no reason the person lied about their methods. They went into more detail but it was a vinegar forced patina.
 
Having broken an M2 Maxamet blade right through the hole, it would make sense for Spyderco to emphasize toughness, not HRC in that area.
 
It really looks like it was masked off prior to the wash.

IF it really related to the material or a differential heat treat it would be showing up on everyone's knife not just this one.
 
If it were differential heat treat I don't think we would see a perfect circle. I also don't think it would be the cutting/blanking method. Wouldn't you see it all around the knife?

My manix2 in maxamet is developing the normal blotchy patina naturally. No circle on mine.
 
Here is the original post and here is the poster's methods:

So I gifted myself the native 5 in Maxamet for my cake day that was last thursday. The knife arrived saturday. It's my 14th spyderco knife and my first native 5. Maxamet is actually my first official non-stainless steel and I'm actually a stainless steel guy but I read about all the other great qualities like hardness of up to 70 HRC and toughness at the same time. Googling pictures of it I quickly stumbled upon pictures showing spyderco Maxamet knives heavily stained or even covered in rust. I initially decided to let it develop patina the natural way and not threat it with oil or grease after every single use cause I wanna EDC this thing. But in my research I also learned about patina actually preventing it from red rust and more importantly that I could force patina it best with warm/hot apple cider vinegar of 5% acid content. So after reading more best practices about "blackening out" non-stainless respectively regular high carbon steels, I became really excited and thought I'd give it a try myself.

I disassembled the knife to handle the blade blade only. I cleaned the blade with cleaning alcohol of 70%. I kept the vinegar heated at like 45* C (113* F) inside a bowl that I kept inside a waterbath constantly being heated to ~80* C (176* F) . Just put the blade inside the vinegar and excitedly waited for results. I noticed the blade becoming slightly grey after a few minutes but not black as some reviews. When I took a q-tip to turn around the blade and check out the bottom side, I noticed that touching /rubbing the blade with the qtip instantly created black marks. So I took it out and rubbed it everywhere so it became black. I then washed of all vinegar and also rubbed it in oil to impregnate it and polish the dark grey/black patina to as even as possible.

Also noteworthy I think, though not entirely helpful, is another person says their Advocate did the same thing when they forced a patina. Although without pictures it isn't exactly compelling.
 
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