Problems with kitchen blades.

A

andybill

Joined
Dec 29, 2008
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I've been making some kitchen knives from old handsaw blades, and have had some real success with the ones I haven't tried to heat treat. They hold an edge well enough for light slicing duties and are very sharp, but the blades are very easily stained by food. Any foods with high acids, it seems, make ugly tarnish marks all over the blade. I know that this kind of steel is susceptible to staining, that's why they make kitchen knives out of stainless, but is there anything I can do at home, some kind of finish or treatment, that will help prevent this?

Also, I tried heat treating some of these knives, and so far, no good. I erxpected the blades to warp considerably, which they did, because they're so thin, but then they failed the file test. After brought up to a bright red/orange and quenched in warm oil until cool, they were still easily marked with a file.
Obviously, I'm new to this, and sorry if this is a repeat question, but any suggestions for either?
Thanks -Andy
 
As far as not getting hard, either you're not getting it hot enough, the quenchant isn't fast enough or there's not enough carbon to get hard. There's also the slight possibility that there's a layer of decarb and the "good stuff" is underneath a thin layer of burned out steel.

I don't know of any finish to use on carbon steel to prevent patination. The best you can do is to immediately clean and oil the blade after use.
 
As far as kitchen knives staining, I prefer them too. No stainless steel in my kitchen :)
And folks that appreciate a good carbon steel knife, don't mind the staining either.

What kind of saw blades? Most are easy to heat treat and harden well, but some don't.
 
Yeah, the staining doesnt bother me either, but I'm going to be selling these at a local craft fair. i'll just include it in the little info card with each one.
The blades are from regular old carpenter's handsaws, the ones with wooden handles that are hanging up all rusty in peoples garages everywhere. Not sure what the steel is, but I figure it's gotta be hard enough cause it's a cutting tool, and very springy.
Not sure what's up with the HT, although I've been using one for about two months that I didnt HT at all and have no complaints. As long as I dont get them too hot while working on them, hopefully they wont lose their temper. They probably wouldnt stand up to hard kitchen use, like chopping up chickens or lobsters, so I'll just keep them small for now. I'll post some pics when i have some.
What do people think about pre-staining them in a controlled manner, any ideas? Maybe create a uniform color that wouldnt look so bad when it gets stained from use.
I'm guessing there's no way of removing the patinization, right?
Thanks for the replies, guys -Andy
 
Don Hanson III said:
As far as kitchen knives staining, I prefer them too. No stainless steel in my kitchen :)
And folks that appreciate a good carbon steel knife, don't mind the staining either.
Click to expand...

Hehe, Don you are probably the only one with a full set of kitchen knives in W2 :D

I have a kitchen knife from 1084, I wipe and oil after use but it still get's this pretty blue patina, looks like the temper colors.
 
andybill said:
What do people think about pre-staining them in a controlled manner, any ideas? Maybe create a uniform color that wouldnt look so bad when it gets stained from use.
I'm guessing there's no way of removing the patinization, right?
Thanks for the replies, guys -Andy
Click to expand...

There are many ways to do that. Among the easiest is to just submerge the blade in a glass or pan of vinegar or lemon juice. You may have to experiment a bit to see how long to soak. Don't leave them in there and forget about them for a month. ;) Or get some Casey's Cold Blue that folks use for touching up scratched guns. If you don't like the patina, you can sand it right off. It's not a super durable coating, just a thin layer of oxidation. It will guard somemwhat against further rusting.
 
Kitchen knives are usually thin enough that you can heat treat and then grind, it really helps with the warpage. Use good belts and not too much speed and quench alot.
 
a 50/50 mix of lemonjuice and vinegar will give the blade a dark gray to black patina depending on the steel, in as little as 3-4 hours I usually let mine go for 6-8. They'll still rust, if you dont oil IMMEDIATLY after washing. nothing like a good patina'd carbon blade to bring a smile to my face.

Jason
 
The blades are from regular old carpenter's handsaws, the ones with wooden handles that are hanging up all rusty in peoples garages everywhere. Not sure what the steel is, but I figure it's gotta be hard enough cause it's a cutting tool, and very springy.
Click to expand...

That old handsaw steel should harden up fine. Not sure what's goin on there.
 
I ran into the same problem with a fillet knife I was making out of a piece of bandsaw.
I think I heated it too long and burned away too much carbon. It would not get hard and
would bend then springing back with a warp. Maybe it could've used a little Viagra... he he
 
I wouldn't try to judge the heat to harden by color. Too many variables. I heat until a magnet won't stick and just a little more then quench in 140 degree oil.
Don't forget to temper. I would start at 350 for 2 half hour sections. Because the steel is unknown you will have to experiment.
Just what I do,
Lynn
 
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