Black Spot on Edge

I was wondering if anyone could shed some light on this. I have a blade that was pro honed early this fall. It is a really smooth shaver and I had been using about once a week. I recently discovered some rust on the toe and tang so I looked at the edge with my pocket microscope. There is a black spot on the edge near the toe. The spot appears to be a small crater on edge but different from other chips I have seen. The area is black and the chipped area does not have a distinct border. It is not reflecting light like a fresh chip.

Is the edge damage rust, or a chip, or maybe a folded edge? I wiped edge off and stropped the razor on my old nylon linen and the blemish is still there. Does anyone have a clear idea of what is going on here? Or maybe pics of different types of edge damage?

Do you have one of those USB microscopes? It'd be good to see a picture.

But... it sounds like rust. If it were a folded edge I think you would see it just as you can see a wire from over-honing. When people restore old blades that have pits they have to hone past those to get a clean edge. You might need to do that on this guy to get the edge back in shape.

Something to think about: if you're getting rust on your blade, consider wiping everything with a clean dry tissue when you're done, getting all the moisture off. (Wipe from the spine outward, being careful not to drive the paper against the edge.) Then strop the razor a few passes on leather to make sure the bevel is clean.

If you keep your razor in the bathroom, you might want to take it out after shaving and put it someplace that gets less humidity. I keep my current rotation on top of my dresser, which is close to the bathroom but much less humid. If you don't have a low humidity environment for storage and you won't use the blade for a while, you might spray with a little WD-40 or wipe some machine oil on it. Or spray it with Ballistol. In any case, make sure all the moisture is off it.

It sounds exactly like corrosion. It happens, even to those of us that think we are ver careful.

Some times corrosion can open up later even if it was not apparent on the freshly honed edge. It's my belief that the corrosion goes deeper into the steel through micro cracks similar to the way steel fails from work hardening.

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Originally Posted by bluesman7

Some times corrosion can open up later even if it was not apparent on the freshly honed edge. It's my belief that the corrosion goes deeper into the steel through micro cracks similar to the way steel fails from work hardening.

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Good point!

Roy (cuddarunner) suggested I keep a light coat of oil on blades that have been freshly honed. New exposed steel ( bevels ) need time to develop a patina, then the oil thing is not so critical.

If the razor is used often, stropping would keep any patina from forming on the bevel.

So this is like a little sinkhole from rust that got through a tiny pore? Or maybe just a tiny bit that got missed under magnification?

Too bad more of us can't take pictures of this stuff. If I had money for a nice microscope I would have some nice hones though!

I suspect the corrosion was from tiny water droplets that were on the blade after the shave that I missed when I wiped the razor off. I think there were a couple of times last month where I was pressed for time and did not strop after the shave like I normally do. Maybe someone will see this thread and direct us to a pic of corrosion on a bevel.

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Originally Posted by MisterClean

Roy (cuddarunner) suggested I keep a light coat of oil on blades that have been freshly honed. New exposed steel ( bevels ) need time to develop a patina, then the oil thing is not so critical.

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I always like to keep oil on any steel surface that has recently been honed or buffed. The freshly exposed steel oxidizes faster than steel that's been exposed.

With that said some people live in climates that are less prone to moisture/thus oxidization/but I'd rather play it safe.

A few years ago I was given seven used vintage razors. None had been honed, stropped or used for at least 50 years. None were oiled but they had been stored in a box in a bedroom chest of drawers on the main floor. With a good stropping all would shave. Shave well? No but better than some factory edges I've tried.

So in my humble opinion if you are in doubt or want to be a bit vigilant, then keep a light coat of oil on your blades (After making sure they are dry) and especially blades kept in an area of your home that may have a higher moisture content in the air.

Better safe than sorry.

You mean something like this ?

Yes, what I have on my blade looks very similar to your pic, onimaru55. My spot is on the very edge, though, and it's hard to tell what is black from corrosion and what is blank space. I wish I could post my own pic.

As you can imagine, those spots would eventually hit the edge with subsequent honing. Then they would chip out into a semicircular shape.
Having one or 2 micropits on an edge is usually no big deal & they can't be felt in the shave unless maybe you have uber soft skin.
Bottom line is, this is rust & as already suggested, oiling is a good maintenance plan but if it's right on the edge wouldn't hurt to hone it out & possibly even clean up the bevel of other potential corrosion.

Almost looks like the swiss cheese edge i posted a few weeks back. Holes all the way thru the bevel. I managed to hone them out and had a great shave afterwards. So if your a honer, hone it out if its on the edge. Get rid of it. It can grow with time.

Any time steel has contact with moisture and oxygen, there is always the possibility of corrosion. The most common oxide of iron is Ferric Oxide Fe2O3. It is the compound we call red iron or rust, a compound sometimes called magnetite.

There is also a Ferrous Oxide with the forumla FeO. Although sometimes called rust, that is not accurate. FeO is black. There are other oxides of iron, but they are less common.

Some steel alloys contain other metals such as Chromium, Manganese, Vanadium, etc. Some of these can also form oxidation products as well.

The best defence against oxidation/corrosion of the blade is to eliminate contact with acids, salts, water, and oxygen. While that is unavoidable during the shaving process, you can minimize exposure afterward by through cleaning, drying, and oiling of the blade.

After every shave, I rinse my blade, dry it on a clean,dry towel, and then coat it with a mixture of a non-toxic oil and 90% isopropyl alcohol. Unlike 70% isopropyl alcohol, 90% alcohol will evaporate and take with it any residual moisture on the blade. This leaves behind a thin film of oil to protect the blade from moisture and oxygen. Some non-toxic oils are mineral oil, Ballistol, and camelia oil.

My oil of choice is Ultra Lube 4-X lubricant and penetrant which is a non-toxic, synthetic oil. I also use it to protect and lubricate tools, fishing reels, guns, etc.

Just a thought, are the scales nitrocellulose? If they're 'going off' newfound rust/pitting like you describe would be expected....

Cheers, Steve

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Originally Posted by Steve56

Just a thought, are the scales nitrocellulose? If they're 'going off' newfound rust/pitting like you describe would be expected....

Cheers, Steve

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Steve, if you look at the first pic at this post you'll see what the first stages of the effects of celluloid scales 'Gassing' looks like (I've seen it first hand). The heavy devastation takes awhile and it's typically not in spots/however some of the tortoise shell look a like can have that but there again they are much larger. I believe that the consensus of there being moisture left did cause the small spots of corrosion.

http://straightrazorpalace.com/works...uloid-rot.html

Yes I’ve seen that fine, frosty pitting from bad scales before, but also on a Geneva I have, some black pitting spots showed up on the freshly honed bevel. Just a thought.

Cheers, Steve

Nothing wrong with thinking :tu

Yeah, I really think the corrosion is from moisture. The scales on the razor in question are horn.

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Originally Posted by Steve56

Yes I’ve seen that fine, frosty pitting from bad scales before, but also on a Geneva I have, some black pitting spots showed up on the freshly honed bevel. Just a thought.

Cheers, Steve

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Freshly abraded steel is more prone to corrosion so a good argument for oiling.