Forced Patina Gone Bad.....????

O

onejim

Joined
Apr 25, 2011
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I finally decided to bite the bullet and try a forced patina. Never done it before. Mostly just cut up a lot of fruit/steak if I wanted to help the patina along.

But this time I decided to try apple cider vinegar. There have been several posts on forced petinas here and there, and I liked the thought of an even dark gray blade.

So I soaked my Case 032 medium stockman chestnut bone (all time favorite pattern, less maybe the STJ) in a little vinegar.

I checked on it every now and then over the course of three hours turning the knife over every now and then.

I decided to keep the blades (all three) partly opened to make sure everything was evenly coated.

A few minutes ago I pulled the knife out............and was very happy with the initial look of the blades, especially after wiping the clip blade off. The chestnut bone even looked better.....little dry, but the brightish red hints and hues appeared to have darkened.

As I started to wipe off the pen blade I noticed there was no friction holding it in place. I didn't think anything of it, assuming something was stuck and that it would clean up fine. Then I noticed the sheeps foot was loose too (both on the same spring). And ....... that's when I realized the spring snapped.

I feel confident that a few hours in vinegar had little to nothing to do with snapping the spring.........but keeping a knife open for a few hours must have been too much stress.

Now thinking of it.......I would never buy a display knife that was in the half way open position, just in case it weakened the spring. So I guess I should have been thinking of that. But I was probably distracted by the wife/kido or just excited to see the end result.

Lesson learned!!!

Just thought I'd share and hear others thoughts.
 
Wow, sorry to hear about your issues with the snapped springs! I have done a forced hot vinegar patina as an experiment, but I only ever dipped the BLADE in the vinegar, never the whole knife, and I stood there holding the knife the whole time, blade fully opened. I heated the vinegar in a glass in the microwave, and then slowly dipped the blade into the hot vinegar, only up to the tang, and not including the joints. That will patina a knife in about 30 seconds.

The only times I have heard about broken backsprings has been with hot stovetop dye jobs, where the entire knife is submerged in boiling water, and someone then rinsing the knife under cold water.
 
I decided to keep the blades (all three) partly opened
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The spring is under the most tension when the blade is midway open. And with two blades on a shared spring... ouch. Even if the spring doesn't physically break, it can lose it's 'spring' action.

Lesson learned.

I was once scolded online by none other than AG Russell for posing a vintage Bruckmann partially open for a photo. :cool:
 
Same thing happened to a nice Indian Head stockman that I soaked in vinegar .Now it has just the main clip blade .Tough lesson .
 
it is sad that your knife broke, but I thought the spring could in principle last forever, holding it half open does not increase the stress outside of its elastic parameters. If A G Russell says otherwise, then I'm not sure what to believe :confused:.

I know others who have got display knives that have been half open for decades in some knife shop display case, which have shown no problem.
 
I had my Queen #9 stockman's spring break on me for no apparent reason. It just happens sometimes.
 
I'm surprised this one hasn't completely fallen apart yet! ;)

Year%20Knife%20Close%20Up.jpg


Contact Case, you may have messed about with the knife, but springs should be more robust than that. Sometimes, rarely, they break unfortunately :thumbup:
 
I only dip the blades in the vinegar when I do this, but I don't think you did anything to break the springs. I believe Case has used stainless springs for a long time anyways. Either way, I still don't think that some vinegar broke the springs.

I'd contact Case. They are pretty good about helping customers out.
 
I have a Schrade 8OT that I gave the dip. I had the clip fully open and the other two about a quarter of the way open, just enough that they wouldn't snap back shut. I had the whole knife submerged for about half an hour. I figured that this was the best way to get all three blades and the backspring and I wasn't worried about the delrin handles. Mine came out fine. If anything I'd say that the spey and sheepsfoot were a little stiffer for a couple days. I figured that was on account of them loosing the polished surfaces that years of opening and closing had given them. Now, it's back to normal with no ill effects. I've also had a stockman with a real tight spey blade that I left overnight with the spey and sheepsfoot open halfway in an attempt to stretch the spring a little bit. It didn't work, the spey was still real tight, but there was no sign that I had done any damage.

I guess what I'm saying is that either I got real lucky or you got a knife with a spring that was bound to snap anyways. I can't say for sure.
 
fatcorgi said:
it is sad that your knife broke, but I thought the spring could in principle last forever, holding it half open does not increase the stress outside of its elastic parameters. If A G Russell says otherwise, then I'm not sure what to believe :confused:.

I know others who have got display knives that have been half open for decades in some knife shop display case, which have shown no problem.
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Having two blades open at the same time places a stress beyond what the spring was designed to handle. Lots of anecdotal evidence either way:
I have an Old Timer knife that was purchased out of a display. It's main spring is noticeably weaker than on similar Old Timer knives. Coincidence?
There was a member on here who set his Swiss Army Knife up for a photo. The blades were only left partially open for a few minutes, but it was enough to ruin the 'snap'.
I think you'll find plenty of others.

It's safe to say some springs are stronger than others. And some knives are less replaceable than others, and not worth the risk.
 
Jack Black said:
I'm surprised this one hasn't completely fallen apart yet! ;)

Year%20Knife%20Close%20Up.jpg
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Who's to say those springs aren't completely shot? If you have two of those to compare, one that's been stored partially open for years and another that's been stored with the blades closed...
 
Geezzz folks, DON'T be soaking entire knives in vinegar, the stuff is really corrosive. Stick your blades in a potato or wrap
them in toilet paper soaked in vinegar. My bet is if you soaked bone in the stuff for long enough the bone would be eaten.
While I'm at it :D HOT water isn't a good idea either. OK, i'm finished my rant.:D
I imagine the spring was faulty but the stress and the corrosivness din't help.

Best regards

Robin
 
PROBABLY caused from being stressed but there is another thing to consider. All acids ( vinegar is acetic acid) have hydrogen as part of their makeup.
There is a phenomenon called Hydrogen Embrittlement. That is where certain steels, normally carbon steels absorb hydrogen atoms into the lattice grain structure of the steel packing the microscopic interstice gaps and making the steel brittle and subject to cracking, usually in the highest stressed areas. I work with aerospace parts (precision gears) and it is a requirement of every spec for plating or other processes involving acids that the parts be given a low temperature bake - usually 300° to 375° depending on the alloy, for from several hours to 24 hours and the bake needs to start within x number ( normally within 4 hours)of hours of coming out of the bath. The low temp bake drives off the absorbed hydrogen but it must be done within a specific time frame or the hydrogen won't be removed.
 
onejim said:
What? I did this and they will replace? You sure?
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Surprisingly they are really good about repairs. Just send it with a nice letter, and ask them nicely. Tell them it is your favorite knife. They have very good customer service. They may repair or replace it.
 
One other note. Before the 'incident'.... I've discussed on here that the knife had a slight metal vibration sound when hit against a hard surface (like my kitchen table).

Someone mentioned that it may be a loose spring, and if it functioned to forget about it. I didn't care much because the knife was a user and it functioned perfectly fine .... great snap/walk/talk/and all. Wonder if this particular knife had a faulty spring from the beginning.

On a side note, the bone looks awesome! Could use a little polish, but it made the chestnut darker and richer.

I plan on contacting Case and seeing what they think.
 
Woodrow F Call said:
I only dip the blades in the vinegar when I do this, but I don't think you did anything to break the springs. I believe Case has used stainless springs for a long time anyways. Either way, I still don't think that some vinegar broke the springs.

I'd contact Case. They are pretty good about helping customers out.
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I agree- but wait was the vinegar being heated during the process? Even if it was I'm not sure it would be enough heat to bugger the spring. I did a hot dye job on a Case saddlehorn trapper with no ill effect. That involved full immersion in very hot liquid. .My thinking is why would they build knives with backsprings which are only just strong enough to cope with the blades being all opened at once even taking into account that everyone knows its a no no ? I reckon the spring was dodgy to begin with.
 
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