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Repairing/Tuning Old Dexter Carbon Chef Knife

OldSaw

The wife's investment
I bought an old Dexter chef knife over 20 years ago and it was well used when I got it. It always had a bit of a hollow spot ahead of the bolster, which has been really annoying. So today I took it to a rough grinding wheel to reduce some of the bolster, which was a step in the right direction.

It was a little rusty and stayed in our summer cottage for most of the past twenty years. I have oiled it and scrubbed it with a Scotch-Brite pad with fair results. Today I hit it with a Scotch-Brite bristle disk and a Scotch-Brite rotary disc pad in a drill motor, which cleaned it up much nicer except for some pitting. This procedure also removed all of the natural patina. After whetting it on a couple of stones I applied some olive oil and wiped it clean with a paper towel. I hope this helps retard the return of rust.

Here’s my questions:

1: What’s the best way to restore the natural shape? Because of the bolster it was badly out of shape for a long time. I’ve restored some of it on my Ken Onion belt sharpener and with whet stones. This was all free hand and it is difficult to reshape as all these efforts want to follow the current shape. I’ve marked the edges of the affected area with a marker and tried sharpening on either side of the marks, with some success. However, I feel like there must be a better way.

Here’s a picture of the area that I’m trying to restore. It’s way better than it was, but still leaves veggie skins uncut because it doesn’t touch the cutting board there.
867EB4A3-45A2-43DC-9E2E-411DEA05931F.jpeg


2: What’s the best way to retard rust formation on a carbon steel knife? I’ve been using olive oil, but maybe something else works better? Avocado oil maybe?
F5641DBC-D720-4D91-B249-AF44FA19EADF.jpeg

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I’d probably bread knife away the high spot on the edge using the side of a course stone. Once the gap is gone, thin the blade, then re set the bevel.

As far as rust prevention, nothing beats patina. Some people force it with dilute warm vinegar, and that will give the most even coating, but you can just chop up a mess of onions and/or red meat, and I like that blue, rainbow look.

C86E7409-135B-455B-BDD4-CD667C70A427.jpeg
 
Such a cool knife that one :).

TBH I think you’re completely on the right track, and quite nearly there.

Firstly re patina - I’d follow David’s advice above and go for rebuilding it naturally. Forced patina tends to wear off after a while. If at any point some little bits of rust start coming back you can just scrub them off lightly so as not to remove most of the grey patina you’ve built up. A thick paste made from bicarb / baking soda with just a little bit of water or lemon juice is good for that. Toothpaste would probably work quite well too. And yeah just oil it occasionally; I like mineral oil because it’s neutral, foodsafe, and you can put on the handle. But any oil will do.

For the shape - first make sure you’ve removed quite a bit of the finger guard - down near the edge it needs to be completely gone. That’s what’ll make life difficult in reprofiling; if you can’t easily and properly sharpen all the way to the heel. Looks like you’ve probably done enough, but maybe just take off a bit more. Finger guards are pretty pointless anyway tbh.

Sketch around the outline of the blade on a piece of paper, then mark on how you want the shape to be when you’re finished. It’s good to have a very solid idea in your head when working.

There are two different ways you can do it; sharpening it back into shape as you’ve been doing. Or as D suggested; ‘breadknifing’ it to get the profile you want, and then sharpening the geometry - bevel & edge - back, i.e. thinning it a bit.

Neither is incorrect, it’s really just preference. I do both but marginally prefer the sharpening way, other people prefer breadknifing. And given what you’ve said - maybe try the latter, it’ll allow you to get to the exact profile you want, then you can sort out the geometry after. It’s nothing more than what’s called ‘thinning behind the edge’ or ‘easing the shoulder’ of where the bevels meet. And you do it simply by sharpening at a more acute angle than your edge, so you’re removing metal just behind the edge, and not raising a burr.

Both methods I like to do freehand on coarse stones, SiC or India are great, as it allows quite fine control, and I’m better at it that way. Though if you’re more comfortable with your belt sharpener or grinding wheel, then by all means do the heavy lifting with those, and it’s going to be quicker like that too.

- - -

I’m sure that’s all just stuff you knew, or David pointed out above. But just to re-iterate the first thing I said; you’re very close to being there already, and you have the kit and knowledge. As long as the finger guard is sorted before you begin on the profile you won’t find it difficult at all :).
 

OldSaw

The wife's investment
Such a cool knife that one :).

TBH I think you’re completely on the right track, and quite nearly there.

Firstly re patina - I’d follow David’s advice above and go for rebuilding it naturally. Forced patina tends to wear off after a while. If at any point some little bits of rust start coming back you can just scrub them off lightly so as not to remove most of the grey patina you’ve built up. A thick paste made from bicarb / baking soda with just a little bit of water or lemon juice is good for that. Toothpaste would probably work quite well too. And yeah just oil it occasionally; I like mineral oil because it’s neutral, foodsafe, and you can put on the handle. But any oil will do.

For the shape - first make sure you’ve removed quite a bit of the finger guard - down near the edge it needs to be completely gone. That’s what’ll make life difficult in reprofiling; if you can’t easily and properly sharpen all the way to the heel. Looks like you’ve probably done enough, but maybe just take off a bit more. Finger guards are pretty pointless anyway tbh.

Sketch around the outline of the blade on a piece of paper, then mark on how you want the shape to be when you’re finished. It’s good to have a very solid idea in your head when working.

There are two different ways you can do it; sharpening it back into shape as you’ve been doing. Or as D suggested; ‘breadknifing’ it to get the profile you want, and then sharpening the geometry - bevel & edge - back, i.e. thinning it a bit.

Neither is incorrect, it’s really just preference. I do both but marginally prefer the sharpening way, other people prefer breadknifing. And given what you’ve said - maybe try the latter, it’ll allow you to get to the exact profile you want, then you can sort out the geometry after. It’s nothing more than what’s called ‘thinning behind the edge’ or ‘easing the shoulder’ of where the bevels meet. And you do it simply by sharpening at a more acute angle than your edge, so you’re removing metal just behind the edge, and not raising a burr.

Both methods I like to do freehand on coarse stones, SiC or India are great, as it allows quite fine control, and I’m better at it that way. Though if you’re more comfortable with your belt sharpener or grinding wheel, then by all means do the heavy lifting with those, and it’s going to be quicker like that too.

- - -

I’m sure that’s all just stuff you knew, or David pointed out above. But just to re-iterate the first thing I said; you’re very close to being there already, and you have the kit and knowledge. As long as the finger guard is sorted before you begin on the profile you won’t find it difficult at all :).
Thanks for the help. I’m not sure what “breadknifing” is. I can google it and see what I find.

I have a tri-stone in my semi truck for my work knife that I believe has a 400 grit stone. It’s just smaller than my Shaptons. I’ll see what I can do with that.

The grinding wheel that I have access to is very crude with a choice of rough and extremely rough wheels. After thinning and rounding the finger guard, I finished it with a handheld die grinder fitted with a thin cutting wheel.

I have a couple hours before work, so maybe I’ll play with it a bit before I head out.
 

OldSaw

The wife's investment
Here’s how it looks now. Not perfect, but knife sharpening is not my hobby, cooking is. So, of course, I need sharp functional knives to do that.

I did multiple back and forth strokes at a fairly acute angle on the coarse stone with my fingers applying pressure on the high spots, with as much blade laying on the stone as possible. When I felt I had most of the high spots down I took it to the 1000 ceramic Shapton. Then the 5000 Shapton. Everything was feeling pretty good at that point, but I couldn’t help running it across my ceramic hone for the final finish.
36B5684F-0AB1-4ABF-89EB-38EAEFA4340E.jpeg


Paper test.
13595693-EA96-419B-8E90-9C3A8BE5F7D1.jpeg

Sliced a tomato with ease. Cut the wedges into pieces with skin side down and they all separated nicely. No long annoying chain of veggies.
55D4ED6D-E1BC-4387-9D5C-F66B5038A324.jpeg

B0822419-3247-4E24-A439-C8EB25BAD142.jpeg


I just spent well over $1,000 on new knives and sharpening equipment, but this old Dexter is such an easy grab that it gets used a lot. I probably should have just spent more on sharpening equipment and less on the ridiculous variety of new knives I bought.
CC2AB9F1-8B2E-4DC6-A6C8-142B46B4EDF0.jpeg
 
Such a cool knife that one :).

TBH I think you’re completely on the right track, and quite nearly there.

Firstly re patina - I’d follow David’s advice above and go for rebuilding it naturally. Forced patina tends to wear off after a while. If at any point some little bits of rust start coming back you can just scrub them off lightly so as not to remove most of the grey patina you’ve built up. A thick paste made from bicarb / baking soda with just a little bit of water or lemon juice is good for that. Toothpaste would probably work quite well too. And yeah just oil it occasionally; I like mineral oil because it’s neutral, foodsafe, and you can put on the handle. But any oil will do.

For the shape - first make sure you’ve removed quite a bit of the finger guard - down near the edge it needs to be completely gone. That’s what’ll make life difficult in reprofiling; if you can’t easily and properly sharpen all the way to the heel. Looks like you’ve probably done enough, but maybe just take off a bit more. Finger guards are pretty pointless anyway tbh.

Sketch around the outline of the blade on a piece of paper, then mark on how you want the shape to be when you’re finished. It’s good to have a very solid idea in your head when working.

There are two different ways you can do it; sharpening it back into shape as you’ve been doing. Or as D suggested; ‘breadknifing’ it to get the profile you want, and then sharpening the geometry - bevel & edge - back, i.e. thinning it a bit.

Neither is incorrect, it’s really just preference. I do both but marginally prefer the sharpening way, other people prefer breadknifing. And given what you’ve said - maybe try the latter, it’ll allow you to get to the exact profile you want, then you can sort out the geometry after. It’s nothing more than what’s called ‘thinning behind the edge’ or ‘easing the shoulder’ of where the bevels meet. And you do it simply by sharpening at a more acute angle than your edge, so you’re removing metal just behind the edge, and not raising a burr.

Both methods I like to do freehand on coarse stones, SiC or India are great, as it allows quite fine control, and I’m better at it that way. Though if you’re more comfortable with your belt sharpener or grinding wheel, then by all means do the heavy lifting with those, and it’s going to be quicker like that too.

- - -

I’m sure that’s all just stuff you knew, or David pointed out above. But just to re-iterate the first thing I said; you’re very close to being there already, and you have the kit and knowledge. As long as the finger guard is sorted before you begin on the profile you won’t find it difficult at all :).
That is what I would have said... Glad someone got to it first. You saved me a lot of typing!
 
Here’s how it looks now. Not perfect, but knife sharpening is not my hobby, cooking is. So, of course, I need sharp functional knives to do that.

I did multiple back and forth strokes at a fairly acute angle on the coarse stone with my fingers applying pressure on the high spots, with as much blade laying on the stone as possible. When I felt I had most of the high spots down I took it to the 1000 ceramic Shapton. Then the 5000 Shapton. Everything was feeling pretty good at that point, but I couldn’t help running it across my ceramic hone for the final finish.
View attachment 1377235

Paper test.
View attachment 1377238

Sliced a tomato with ease. Cut the wedges into pieces with skin side down and they all separated nicely. No long annoying chain of veggies.
View attachment 1377239
View attachment 1377240

I just spent well over $1,000 on new knives and sharpening equipment, but this old Dexter is such an easy grab that it gets used a lot. I probably should have just spent more on sharpening equipment and less on the ridiculous variety of new knives I bought.
View attachment 1377242
Looking like it worked out well! You can tinker around with it more if you need to but I'm guessing you won't need to much to it for a while besides rudimentary edge maintenance.

My favorite method for patina is just using it. Onions, meat, pineapple... whatever. Use it then clean it. It'll be great.

If its a cottage knife and is going to sit for a bit during the off season, hit it with some crisco or something. Should be fine!
 
I have the Ken Onion edition sharpener for my knives and axes, but I am not sure what I would have done with that. Probably the wrong thing! Without a Tormek, I probably would have spent 4 hours refiling the entire thing like an axe that got nicked. One of the belts on the Ken Onion probably could do it, but I hate the thought of ruining something older than I am. You did good in your restraint!
 

OldSaw

The wife's investment
Looking like it worked out well! You can tinker around with it more if you need to but I'm guessing you won't need to much to it for a while besides rudimentary edge maintenance.

My favorite method for patina is just using it. Onions, meat, pineapple... whatever. Use it then clean it. It'll be great.

If its a cottage knife and is going to sit for a bit during the off season, hit it with some crisco or something. Should be fine!
Thanks. It’s not a cottage knife anymore though, because we tore the cottage down and built our current home in its place. So everything has been combined and/or given away.

I went bonkers buying new cookware and knives, and then sharpening devices.

I didn’t think I would ever need a coarse sharpening stone (other than the small one in my truck), but after this project I ordered a 400 Shapton. It wasn’t very expensive and now I can do a better job on this knife when I get back home. Plus, I can rejuvenate some of my neighbors’ knives as well.
 

OldSaw

The wife's investment
I have the Ken Onion edition sharpener for my knives and axes, but I am not sure what I would have done with that. Probably the wrong thing! Without a Tormek, I probably would have spent 4 hours refiling the entire thing like an axe that got nicked. One of the belts on the Ken Onion probably could do it, but I hate the thought of ruining something older than I am. You did good in your restraint!
I really thought the Ken Onion sharpener was going to save me a lot of time and expense over water stones. It is the best electric sharpener I have ever used and is probably above average for most people and their average knives.

But all it really did was show me that I still needed/wanted regular stones. So now I have both and am hopeful that I won’t slip deeper into buying even more knives and equipment.
 

kelbro

Alfred Spatchcock
I'm a little ashamed to admit that the belt sharpener gets top billing over the stones these days for kitchen and butchering knives. Razor edges in seconds/minutes, not hours and those edges are very easy to maintain. None of my tools are collectibles so I'm not a bit worried about taking an extra millionth or two off with high speed abrasives.
 

OldSaw

The wife's investment
hopeful that I won’t slip deeper into buying even more knives and equipment.

@OldSaw

Stay out of thrift stores & pawn shops LOL
It’s Cutlery and More that I have to stay away from. I could handle a few thrift store knives if they were decent quality, but usually all I ever find is junk. That 20% off email sale had me buying at least a half dozen more knives than I needed.
 

OldSaw

The wife's investment
That was such a good idea you gave me. I stopped at the local thrift store and picked up a couple of cheapies to practice on.
View attachment 1379735
Quoting my own post as a follow up. I was sadly disappointed to see Emeril Lagasse’s name on such a chintzy knife. Yet, of the “recycling bin ready” knives that were there, it was probably the best.

Another reason for picking up a few cheap knives is that my family likes to make chicken booyah (it’s a Green Bay, WI area thing) once in a while. It’s a group event and we usually make a 20 gallon (small) batch. The night before, we all get together in one of our garages and cut vegetables. Now I will have a few more knives available for the “helpers.” Usually, everyone is working with fairly dull knives and almost never a knuckle saving chef/chopping knife.

So in the interest of protecting my good knives, I consider these the cheapest insurance/investment toward that end.
 



Here’s my questions:

2: What’s the best way to retard rust formation on a carbon steel knife?​


Mineral Oil is what you seek.
 

OldSaw

The wife's investment

Here’s my questions:​

2: What’s the best way to retard rust formation on a carbon steel knife?​


Mineral Oil is what you seek.
I think I need to get a small bottle to keep under the sink, so I can apply it right after washing.
 
I think I need to get a small bottle to keep under the sink, so I can apply it right after washing.
I made my own blade balm which I find easier to apply. I used Japanese Camellia oil and castor wax I think. The key is to use a wax that is hydrophobic and food safe. It's pretty easy to find a basic balm recipe online and use or improvise a double boiler. If you get it wrong, just remelt and try again.
 
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