Seasoning a carbon steel knife.

I

Igot_it

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Jun 26, 2021
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Hey all brand new blade smith, first post here, question on carbon steel finishes. I noticed that after hardening in vegetable (canola) oil my blades develop a very interesting patina.Forge scale and oil. Of course it goes away with grinding. But I started tempering in the kitchen oven and I realized that the temp (375) is exactly the same temp I use to season cast iron and carbon steel woks. After the first tempering cycle I rubbed the blade with olive oil and put it in for a second temper. Olive oil has a low scorch temp so it formed a kind of varnish finish at the end. Basically it looks like the outside of a wok. Has anyone else ever tried this type of finish? Just curious if I’m wasting my time with it.
 
Igot_it said:
Hey all brand new blade smith, first post here, question on carbon steel finishes. I noticed that after hardening in vegetable (canola) oil my blades develop a very interesting patina.Forge scale and oil. Of course it goes away with grinding. But I started tempering in the kitchen oven and I realized that the temp (375) is exactly the same temp I use to season cast iron and carbon steel woks. After the first tempering cycle I rubbed the blade with olive oil and put it in for a second temper. Olive oil has a low scorch temp so it formed a kind of varnish finish at the end. Basically it looks like the outside of a wok. Has anyone else ever tried this type of finish? Just curious if I’m wasting my time with it.
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Interesting. I have no idea. However I will follow along for other responses.
 
Sealing a pan which has a certain amount of pores and irregular surfaces, and putting the same coat on a knife blade make out of hard steel with a smooth surface would be two different things. You would make the knife less efficient y coating it with the "oil varnish". If you like a patina, use any of a dozen or so techniques to get a darker or aged look. These range from FC, to vinegar, to mustard, to gun blue an bleach, ... even coffee. Search "forced patina on knife blade"
 
Stacy E. Apelt - Bladesmith said:
Sealing a pan which has a certain amount of pores and irregular surfaces, and putting the same coat on a knife blade make out of hard steel with a smooth surface would be two different things. You would make the knife less efficient y coating it with the "oil varnish". If you like a patina, use any of a dozen or so techniques to get a darker or aged look. These range from FC, to vinegar, to mustard, to gun blue an bleach, ... even coffee. Search "forced patina on knife blade"
Click to expand...
Ahhhh yeah I forgot to mention I left the knife surface intentionally rough (finished with 80 grit) to give it some purchase on the steel. Maybe you are talking about steel pore size, cast iron definitely has that, but woks are made from carbon steel, and they use a similar process for seasoning. Of course chefs aren’t typically blade smiths either…..
 
I guess this is kind of a low temp version of lamping, a hot oil. Finishing process used on small metal parts.

Most makers will be grinding again after temper so would need to run it through another temper cycle before final handle fitup. If you like the look of it do a couple of coupons and chuck em outside with a control piece (no oil) see if it helps corrosion resistance
 
Natlek said:
Any picture so we can see that olive oil finish ?
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Sure. It’s actually really hard to get a picture that shows it well but it’s kind of an olive drab camo pattern. The handle isn’t shaped yet obviously. I was planning on just grinding in the edge bevel and false edges being the only bright parts of the blade. Be kind it’s only my third knife…😁
ETA ok how do you upload a picture?
 
Nick-D said:
I guess this is kind of a low temp version of lamping, a hot oil. Finishing process used on small metal parts.

Most makers will be grinding again after temper so would need to run it through another temper cycle before final handle fitup. If you like the look of it do a couple of coupons and chuck em outside with a control piece (no oil) see if it helps corrosion resistance
Click to expand...
Is that like waxing forge scale? When I make other items like door hardware my dad taught me to rub beeswax to get a little finish on it
 
aBbi5ER.jpg

There's your pic.
 
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