Vinegar destroying knife restoration?

T

TheApogeeEvent

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Jul 31, 2019
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I have recently soaked a vintage knife in white distilled vinegar. The knife had barely any rust on it, but after soaking it in vinegar for a couple of days I took it out and it was severely pitted all over including so much pitting on the edge it went from a straight and fairly even edge to essentially a serrated edge. Why does this happen? Am I soaking it too long? Does the vinegar go beyond loosening and removing rust to actually eating away at the blade or are the knives I've done this with have smaller rust and pitting that I don't initially realize? The blades are ruined...

 
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Yeah, you shouldn't soak it in vinegar for 2 days. It's still acidic and will attack the steel.

You might be ok soaking it for a few minutes, maybe an hour. Then you need to rinse the vinegar off the steel. I would apply a light coat of oil afterwards.

Hopefully it wasn't a costly mistake.
 
Explain to me like I'm 4 years old why you thought this was a good idea in the first place. Not trying to troll, honestly. I'm genuinely curious as to why.

Edit: indeed, vinegar is an often recommended rust remover, and a quick Google search brings up a pile of advisories saying to go ahead and let it soak overnight. What none of them recommend is testing the reaction first to make sure your steel can handle it, or to dilute the acid based on the amount of rust to be removed. What you may have is a high carbon blade, which you would not dip into vinegar but for a minute for an advanced patina effect.

Im still curious, though, why you left it in there for days. That's too long by any account.
 
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I can't say I've never made an oops like that. We all learn the hard way sometimes. Here's hoping there's enough metal left to save.
 
The problem is that you soaked it in vinegar in the first place.
It's acidic and beyond taking the rust off it effects the surface of the steel, it turns the steel an ugly dark dull grey and of course will corrode the steel if left too long.
Next time you should first try steel wool and wd40, especially on less significant it'll work in just a couple minutes.
That's about as much time as it takes to set up the container and fill it...etc but without the waiting for results.
Vinegar technically works and can be the right choice for some things, just not knives and tools in my opinion.

It is my opinion that people who recommend this for vintage hand tools and knives don't know what they're talking about, these are people who probably think everything old needs to look " new " in order to have any practical value and these people probably think taking something old and mirror polishing it is a " restoration "
 
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Hickory n steel said:
The problem is that you soaked it in vinegar in the first place.
It's acidic and beyond taking the rust off it effects the surface of the steel, it turns the steel an ugly dark dull grey and of course will corrode the steel if left too long.
Next time you should first try steel wool and wd40, especially on less significant it'll work in just a couple minutes.
That's about as much time as it takes to set up the container and fill it...etc but without the waiting for results.
Vinegar technically works and can be the right choice for some things, just not knives and tools in my opinion.

It is my opinion that people who recommend this for vintage hand tools and knives don't know what they're talking about, these are people who probably think everything old needs to look " new " in order to have any practical value and these people probably think taking something old and mirror polishing it is a " restoration "
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I’ve done vinegar dips on many blades without issue. The issue with the OP is that he left it in for 3 days. My recipe is 30 minutes and I always set a timer. Some folks like the gunmetal grey patina’d look. Vinegar bath is perfectly fine as long as you rinse and apply oil afterwards. One and done. Plus, once you get this gunmetal grey layer on the blade, it’s less susceptible to rust or corrosion.

Steel wool puts scratches and swirl marks in your blade and to me, that doesn’t make a lot of sense.
 
There is also bronze wool which should be harder than rust, but softer than knife steel. Little to no scratching and no rusting or other steel wool issues.
 
The only thing vinegar is really good for is removing scale off of heat treated metal.

Somehow, soaking everything in vinegar has been widely promoted on the Internet by amateur metalworkers.
It's a terrible way to remove rust, it discolors steel deeply, and it promotes after-rusting.

EvapoRust is good, as is "Must for Rust"-which is a phosphoric acid rust remover.

Fine steel wool-used dry is a good start for removing rust. Using it with oil creates a slurry of iron oxide which will abrade steel. This is especially true when oil/steel wool is used on blued firearms. Use it dry, shake it out, wipe the loose rust off.

Leave the vinegar in the kitchen where it belongs, and ask real experts before doing something that could potentially damage your knife. And remember, most Internet posters are NOT experts.
 
91bravo said:
I’ve done vinegar dips on many blades without issue. The issue with the OP is that he left it in for 3 days. My recipe is 30 minutes and I always set a timer. Some folks like the gunmetal grey patina’d look. Vinegar bath is perfectly fine as long as you rinse and apply oil afterwards. One and done. Plus, once you get this gunmetal grey layer on the blade, it’s less susceptible to rust or corrosion.
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I still would never do it because I don't like the results and absolutely cannot stand the smell, especially on something that will have a better looking natural patina underneath the rust.
Plus rust can be converted.

everybody has their own processes and opinions, and I suppose there's no right or wrong when dealing with your own property and getting results you're happy with.
 
Next time try 0000 steel wool (not the regular stuff they sell at grocery stores for washing dishes) and any type of oil. It won’t scratch at all, and it takes off surface rust no problem. Then wash it, dry it, oil it, and it’s done.
 
This middle knife is an old Canteenshop Woodcrafter that I did a vinegar dip on back around 2010 when I first got it. O1 steel. Here it is, 15 years later with no rust on it, despite sitting in that leather sheath inside a shoebox in the garage. The vinegar dip did its job. Some darkened patina spots on the blade, but no rust. Plus, I like the 2 tone look.

IMG_7219.jpegIMG_7223.jpegIMG_7224.jpeg
 
There was some pitting on the blades with rust in them that I felt needed to soak a bit longer to clean out. Fortunately these were not rare or expensive blades. I'm definitely going to do better next time to clean old blades. Thanks for all of the suggestions guys!
 
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