Oiling old bone?

[r8shell]

I'm looking at an old pocketknife. It has a tiny crack in the bone scale at the pin, but otherwise looks like it was never used. Can bone crack from something like temperature changes or dryness? Would putting mineral oil on help prevent this ?
When I find an old knife at a yard sale or whatever, I clean it and oil the joints with mineral oil. Some always gets on the handle and it makes it look great, but is the oil actually good for the scales? Any reason it would be bad for them?

 

[Modoc ED]

Most likely, the crack in the cover you're talking about is a stress crack although dryness and extreme temperatures can contribute to cracks in bone and other materials too.

A lot of guys use mineral oil on their covers with no problems. I use RemOil and sometimes lemon oil, actually, pretty much whatever is at hand. Some people recommend Fromby's Lemon Oil. If it gives you any peace of mind, I think Fromby's is what Tony Bose recommends.

 

[CUTS LIKE A KRIS]

I'm not an expert, but after hearing differing opinions on oil on old bone I decided to test it out for myself. I removed a cracked scale from a knife I want to "repair" some day and sectioned it into 4 pieces: a control and 3 testers. Each of the testers went into a ziplock of heavy mineral oil. At 2 weeks, one month and 2 months I took the appropriate one out (each individually wrapped, then left out of oil to ensure only the limited time), tested surface hardness and color. The oil hardly penetrated into the scales either, superficial scratching reveals dry bone beneath the surface. Not using any scientific testing gauges, and being my personal opinion only- I found that the oil made no negative impact on the bone. I re-placed the 2 month bone into submersion, and plan to check it at 6 months and again at a year to see what occurrs. While I can't speak for anybody but myself, I am going to continue oolong my knives as I see fit. My uses will keep them in rotation, so it isn't like they will be away from skin oils either, but I don't feel that occasional oiling will be detrimental to the scales.

Others may feel differently.

 

[supratentorial]

I don't think that mineral oil will help. If it is a user and not a collectible, you might use a paste wax but it only affords protection to the surface. Here are a couple of good posts on the topic:

Don't put mineral oil on horn or bone. It will ruin bone in short order, and it does nothing for horn.
Use paste wax or paste neutral shoe polish.

Yes, that's the stuff.

2-3 drops on a soft rag, wipe down the metal parts.

A drop or two won't hurt most handle materials, BUT slobbering it on will discolor bone or ivory, weaken leather.

2-3 drops on a soft rag. THAT IS ALL. Don't glug-glug it :barf: all over everything.

*

Mineral oil won't HURT the wood of a cutting board, but oiling a board :thumbdn: defeats the antibacterial properties of dry wood.

So for pretty, use oil. For health, use NOTHING but soap and water.

http://www.knife-expert.com/cut-bo93.txt

If you're the kind of kid who doesn't wear a bike helmet because it would mess up your hairdo then go ahead and oil that cutting board.

*

Modern Japanese "sword oil" is merely scented mineral oil.

"Kentucky Mint" means buffed out, with a closed surface.
A Japanese sword polish is done with stones only, to OPEN the grain.
They might LOOK the same( to a California hillbilly), but they're not. They are opposites.

*

For a badly rusted knife or tool, soaking in mineral oil won't hurt, and might possibly help.

Otherwise: 2-3 drops on a soft cloth.

BRL...

Re: mineral oil.

DO NOT SOAK bone or other organics in oil. Bone will absorb the oil like a sponge, changing the color.
Dirt dissolved in the oil will darken the bone, too.
Kind of like having a Kentucky visa stamp in your passport.
Although in KY they first stain the bone with strong tea or tobacco soup, THEN soak it in oil.
Gives it that rich honey color so popular on ebay, one that no knife factory ever used.
...

 

[rma100]

I would just like to add that any Silicone based lubricant;ie Rem Oil etc.,tastes absolutely HORRIBLE if you use your knife for food prep!

 

[Modoc ED]

I would just like to add that any Silicone based lubricant;ie Rem Oil etc.,tastes absolutely HORRIBLE if you use your knife for food prep!

I don't see the problem. I've been having steak, eggs, and RemOil for breakfast for years. The grape jelly on the toast masks the RemOil nicely.

 

[supratentorial]

Ed, I enjoy your posts and hope that you will be active on the forum for many years. Please switch to mineral oil.

 

[Obsessed with Edges]

The food safe mineral oil ('laxative' type) DOES NOT ruin bone. It's chemically inert, and won't do anything but fill up empty space in the bone, like the 'pores' in it. That's good enough protection in itself, in that pores filled with mineral oil won't soak up water. I could see some other 'oils' potentially causing damage; especially if there are solvents or other harsh chemicals in the mix. I cringe every time I hear of some of the automotive-grade stuff (motor oil, transmission oil, etc.) being used on natural materials, because there often are other solvents, detergents and other harsh chemicals there. If they come with warnings about potential health risks (carcinogens, etc.), that's enough for me to avoid using it for other-than-intended purposes.

As indicated in an earlier post, bone barely absorbs much mineral oil anyway (the referenced experiments are in line with what I've seen, when I've oiled the bone scales on mine). I'm perplexed by the mention of bone soaking up oil 'like a sponge'. I've never seen this on any of my knives ('70s vintage and later), and I've tried; maybe it happens on really old, really DRY & untreated bone, as in true antiques (maybe BRL was speaking with this in mind?). The advice given by Levine in the other quoted text is good, regarding LIGHT application. Whatever oil is applied, a minimal amount will do. The rest won't absorb into the bone, and will need to be wiped off anyway.

I tend to believe that once a crack starts in bone, oiling alone won't fix it, or even prevent it from spreading. Cracks in bone usually start with stress by machining (drilling), impact, or bending/twisting (near pins, especially). Whatever repairs are done, I think usually involve filling or stabilizing the crack with adhesive or epoxy.

 

[supratentorial]

I think it depends on what you mean by "ruin". I think Bill and Bernard were both referring to the color, not the structure. Mineral oil is a solvent. As BRL said, a drop or two won't do much. Incubation in it could change the color.

Edit:

I do incubate badly rusted knives in mineral oil. In that case, the color of the bone is of less concern.
Bernard Levine: "For a badly rusted knife or tool, soaking in mineral oil won't hurt, and might possibly help."

For a valued antique, incubating in mineral probably wouldn't be desirable... except to a certain market.
Bernard Levine: "Gives it that rich honey color so popular on ebay, one that no knife factory ever used."

 

[richstag]

I have never had a problem with bone and oil. Wood, yes, stag yes. I have been told oil is a big no no with stag because it just softens it over time.

I get oil on my stag 73 everytime I sharpen it...well, until I stopped using too much honing oil. It ended up turning it yellow. Most bone is died so I don't see much of an issue anyhow.

On bone, I was under the impression oil was not a bad thing but actually a good thing?

 

[cnas122]

Neither bone nor stag will "soak" up oil. It's not porous enough. It won't hurt it structurally, but it's can affect the color.

Personally, I only use mineral oil on knives that come into contact with food (even my EDC's) because it's safer.

 

[Modoc ED]

Ed, I enjoy your posts and hope that you will be active on the forum for many years. Please switch to mineral oil.

Jake -- I appreciate your concern but I gotta say that RemOil not only keeps the blades operating smoothly but also keeps me solid. Mineral oil, on the other hand, kinda keeps things a little loose. Just look at David's lead in sentence to his post right after your's -- "The food safe mineral oil ('laxative' type) DOES NOT ruin bone."

No matter what oil we use for our knives the old saying; "A little dab 'ill do ya" suits this situations just right.

 

[richstag]

Neither bone nor stag will "soak" up oil. It's not porous enough. It won't hurt it structurally, but it's can affect the color.

Personally, I only use mineral oil on knives that come into contact with food (even my EDC's) because it's safer.

How does it change the color so quickly if it doesn't soak it up?

I was also under the impression that Ivory, that is a tooth, is the only of the natural materials that won't soak up oil.

Idk for sure. It would be good to get to the bottom of this one.

 

[Obsessed with Edges]

I think it depends on what you mean by "ruin". I think Bill and Bernard were both referring to the color, not the structure. Mineral oil is a solvent. As BRL said, a drop or two won't do much. Incubation in it could change the color.

Edit:

I do incubate badly rusted knives in mineral oil. In that case, the color of the bone is of less concern.
Bernard Levine: "For a badly rusted knife or tool, soaking in mineral oil won't hurt, and might possibly help."

For a valued antique, incubating in mineral probably wouldn't be desirable... except to a certain market.
Bernard Levine: "Gives it that rich honey color so popular on ebay, one that no knife factory ever used."

The catch is, it's a solvent only of other products based upon it (based in mineral oil, in other words). It's not chemically capable of dissolving anything else.

I can see a color change, as a result of the pores/cracks/voids getting filled in the material. Sort of like fabrics or wood getting darker when absorbing water. Cosmetic difference, but not necessarily harmful.

Bill (DeShivs) has frequently commented in the Maint forum on difficulties of repairing bone or other natural materials soaked in oil, I think from a perspective of it making adhesion (with glues/epoxies) more difficult. I suspect that has more to do with his view on the topic.

 

[supratentorial]

The catch is, it's a solvent only of other products based upon it (based in mineral oil, in other words). It's not chemically capable of dissolving anything else.

I can see a color change, as a result of the pores/cracks/voids getting filled in the material. Sort of like fabrics or wood getting darker when absorbing water. Cosmetic difference, but not necessarily harmful.

Bill (DeShivs) has frequently commented in the Maint forum on difficulties of repairing bone or other natural materials soaked in oil, I think from a perspective of it making adhesion (with glues/epoxies) more difficult. I suspect that has more to do with his view on the topic.

Do you mean oil soluble dyes?

 

[richstag]

When I asked in the maintenance forum about why folks use lemon oil for stag, here is the best response I got:

Lemon oil, mineral oil, motor oil, no oil is good for stag. It soaks in and softens and discolors it.
Oil does nothing for ivory except make it slick.
Use paste wax for both materials, use lemon oil for furniture, and use mineral oil as a laxative.

Also on Ivory and mineral oil debating the concept of preserving Ivory's natural oil:

Ivory doesn't contain any oil naturally. It's a tooth.

 

[supratentorial]

I wonder what dyes were used on the oldies... and their solubility properties. Bill and Bernard have a lot more experience with knives than me.

 

[Obsessed with Edges]

Do you mean oil soluble dyes?

Like that, yes. I've heard mineral oil was/is used in some printing & painting circles, as a cleaner to clean up mineral oil-based paints and printing inks.

If comparing to dyes used in bone, I'm thinking most of these dyes were based in something else entirely. Oil-based dyes in bone wouldn't last long at all, if exposed to WD-40 and any other oil & solvent-based products we now use on our knives (including mineral oil).

 

[Obsessed with Edges]

This is the advice given by Case, for maintaining their knives (and presumably all handle materials on them):

(from site: http://www.wrcase.com/case_college/collector_advice/caring.php )

(bolded emphasis added by me)

"Cleaning Blades and Handles

Apply a small drop of oil in the joints of your knife and a small amount of oil on a clean, soft rag or cloth. Then, wipe down the blades and handles with the soft cloth. The inside of the knife can be cleaned with the cotton-tipped swabs and wooden tooth picks. Take special care when using pipe cleaners to avoid scratching the surface with their wire core. Toothpicks or toothbrushes can be used to clean out the crevices in the jigging and other small areas where gunk can accumulate. "

What catches my eye is, even Case doesn't get specific as to the type of oil used. Just 'oil'. That suggests to me, they're not too worried about the scales being damaged or otherwise altered by a light oil wipe-down.

 

[kc custom]

I've thought for some time before responding to this thread. If there is a way to reliably dye bone
without first infusing some form of oil into it I'd like to know about it. I think its safe to say I've dyed
hundreds of sets of scales in 5-8 years and unless the bone contains enough animal fat (or some form
of oil) the bone won't even accept the dye (oil based dye). Not to say there aren't different methods.
I'm talking about thru & thru solid color that stays there, not exactly an easter egg dip of water or
alcohol based dyes. Instead of running to hide- I'll continue with my methods.
Ken.