Blade discoloration?

[AlaskanCelt]

Hey guys, I'm new to the forms and new to knife making. I had a question about a knife I made and the blade I bought from Lauri knives. After I finished it and made a horizontal belt leather sheath for it and now the blade has discoloration on it. Is it from being in the sheath overnight? I wrapped it in plastic wrap to form it so not sure why.
Gonna try and upload pictures, but we'll see if it works.

 

[irona]

The pictures don't seem to be working. What kind of steel is the blade made out of? My best guess is that the blank is made of some kind of carbon steel and what you're experiencing is a patina. Patina is generally considered to be a good thing - it forms a layer of oxidation on the steel that prevents rust.

 

[NJBillK]

Did you use vegetable tanned leather?
If not the materials used will be Very corrosive to a carbon steel.

 

[Obsessed with Edges]

The Lauri Knives site lists their blade steel's composition as something roughly akin to a 1080/1085 (maybe a 'CV' variant of the same, with tiny bits of chromium and vanadium added). Fairly high carbon at 0.81%, and NOT stainless at all (not nearly enough chromium at only 0.54%). If this is what you've got, it's likely developing a 'patina' as mentioned, and could likely be due to a reaction to acidic tanning chemicals and/or moisture left in the leather sheath you made. If the patina is just grey or black oxide, no worries about damage to the steel. If there's any brown or red there, it may be rust (red oxide). Rub a white pencil eraser on it, and see if any brown or red staining shows up on the eraser (that'll be rust).

"High quality Finnish carbonsteel blades. Bolsters, caps and ferrules available in brass and nickel. Traditional scandi grind with one single bewel. Steel analysis Carbon steel: Tempered HRC 59 C-0,81 Mn-0,56 S-0,004 P-0,01 Si 0,35 V-0,161 Cr-0,54 "

Safest bet in the short term, is to not store the knife in the sheath for long periods of time (daily use should be OK), if the sheath is contributing to the discoloration. Keep the blade oiled and clean.


David

 

[maxxmadd]

I agree, it sounds like a slight rust or a patina. Do some research; you may need to protect the blade with a coating of some kind. Wax, oil, gun bluing, or a controlled forced patina(orange juice,lemon,vinegar ect). Google is your friend.