Thread: I need advice on a crumbling edge.

Sidneyk ~ You know the funny thing is , after all the work i put into mine, I only shaved with it half a dozen times, now preferring to keep it away from water. Guess I became a collector

Bart ~ Fingers crossed for you mate. Hope you strike the mother lode of healthy steel.

I had a similar problem with a razor, but it was a full hollow, with a large stretch of ultrathin metal. Thin enough that squiggles of corrosion had gone all the way through even in the middle of the blade, rather than just near the edge. So there was no "getting past the corrosion." It was a matter, rather, of slowly receding the edge in the hopes of hitting a blade-long stretch of strong metal – with the knowledge that more bad metal lay beyond. That future honing, in other words (perhaps years down the line, but still) would land me in another corroded patch.

I assumed that's what you were encountering until I saw the pics and read that it was a wedge. I have to admit this is odd for a thick razor. But I guess a squiggle of corrosion can keep penetrating deeper, like a worm in an apple.

Good luck. Like Sandy, I'm confident the razor's in good hands.

Originally Posted by OLD_SCHOOL

Does that make better sense yet? Perhaps not, I do find it difficult to display ideas and or thoughts in writing, where there is no body language or emotion involved.

Made perfect sense to me OS .

8 layers of tape?!?! Measure that and see what kind of bevel angle you're dealing with. I'm guessing you're close, if not out of range. I'd say use 1 layer of tape if you want to avoid (further?) hone marks on the spine. My feeling is that manipulating the bevel angle to get an edge that won't crumble is futile. Using exotic stones and techniques to hone the edge without having it crumble is futile. Any edge you acheive with such methods won't be serviceable and wouldn't be maintainable thereafter either. The chances of a particular blade being radically different (steel-wise) from all the others of it's brand and model are pretty much nil. Continue with normal honing and you'll either get into good steel if there is any or you won't if there isn't.

Originally Posted by Quick

8 layers of tape?!?! Measure that and see what kind of bevel angle you're dealing with. I'm guessing you're close, if not out of range. I'd say use 1 layer of tape if you want to avoid (further?) hone marks on the spine. My feeling is that manipulating the bevel angle to get an edge that won't crumble is futile. Using exotic stones and techniques to hone the edge without having it crumble is futile. Any edge you acheive with such methods won't be serviceable and wouldn't be maintainable thereafter either. The chances of a particular blade being radically different (steel-wise) from all the others of it's brand and model are pretty much nil. Continue with normal honing and you'll either get into good steel if there is any or you won't if there isn't.

8 layers of tape is a over the top. I knew that up front. But I wanted to see if I could create an undamaged edge, even in the problematic part of the steel. Combining a steep angle, very gentle hones and some serious stropping on CrO, I could succeed in that.
But this edge couldn't the shaving forces. At least, not at the weak part of the steel. I suspected that much, but at least now I know for sure that it makes no sense sharpening the "crumblesome" steel.

On another note: these old wedges were not always honed with the edge laying flat on the hone. Glen got me thinking on that one in this thread, a while ago. http://straightrazorpalace.com/advan...ned-day-2.html. I have honed a few wedges ever since reading that thread, that changed my views on the subject. I usually start out with 3 layers of tape on them, not just to protect the spine, but to get more consistently even and less wide bevel panes. I've went as far as 5 layers on wedges with heavy spine wear, and got premium results.
But 8 layers of tape on this W&B was definitely too much.

OldSchool, your input was and is certainly valued. I believe I understand what you are suggesting. But I have examined this blade long and thoroughly under magnification. The steel crumbles as soon as it becomes too thin near the apex of the edge. But there's nothing to see to predict it: the small parallel cracks I spoke about, only occur near the very edge, prior to the crumbling. Other than the crubling, the affected steel looks precisely the same as the sound part of the edge.

Best regards,
Bart.

Here’s one theory -

“The combined effects of stress and corrosion can result in a special type of failure known as Stress Corrosion Cracking (SCC). This arises under a particular set of circumstances for a given alloy: specific alloy condition plus specific corrosive media and sufficient local tensile stress. Chloride induced cracking of stainless steels, caustic cracking of plain carbon steels and ammonia damage to copper alloys are typical examples of this problem.

SCC is believed to be nucleated at pitting damage sites and develops under the action of local tensile stresses as a highly branched network of fine cracks. At each crack tip the combined action of the tensile stress and specific ions in the corrosive media cause continual crack propagation with little evidence of local deformation.

Stress corrosion cracking presents an especially difficult problem, since not only is it highly localized but it can occur in environments that are merely mildly corrosive to the material. The damaging concentration of the harmful ions in that environment may be quite small and difficult to detect and, even in the absence of applied stress, residual stresses in a structure can often be of a sufficiently high level to cause SCC and failure in service.
In a given situation the time of exposure needed to cause SCC failure depends on the stress intensity at any pre-existing or developed crack tip. The concentration of stress at the tip of a sharp crack or flaw can be quantified in terms of the Stress Intensity Factor, K1. It determines the growth rate of SCC cracks for a specific alloy environment combination. Catastrophic failure of a component will occur when this factor reaches a critical value, the Fracture toughness of the material, K1C. This enables the determination of allowable defect size in design to avoid failure under given loading conditions.”
Your fine old Wade & Butcher has likely been exposed to over 100 years of corrosive influences and in all probability the stress induced in the polishing & honing process was sufficient to begin the failure.

There is obviously no way of telling how far the micro-cracking permeates the metal or how much will have to be removed to find that perfect edge, but I wish you good luck!

Thanks Casey302.
This is an extremely interesting post. It explains why I can't see actual corrosion pitting at the edge, but still experience disintegrating steel. It also sounds very much in concordance with everything I'm experiencing with this blade, that certainly has been stored in corrosive conditions, based on the pitting present on the blade.

The knowledge present at this forum never seizes to amaze me.

I indeed hope that I can get past the problem zone.

Bart.

Originally Posted by Casey302

Here’s one theory -

“The combined effects of stress and corrosion can result in a special type of failure known as Stress Corrosion Cracking (SCC). This arises under a particular set of circumstances for a given alloy: specific alloy condition plus specific corrosive media and sufficient local tensile stress. Chloride induced cracking of stainless steels, caustic cracking of plain carbon steels and ammonia damage to copper alloys are typical examples of this problem.

SCC is believed to be nucleated at pitting damage sites and develops under the action of local tensile stresses as a highly branched network of fine cracks. At each crack tip the combined action of the tensile stress and specific ions in the corrosive media cause continual crack propagation with little evidence of local deformation.

Stress corrosion cracking presents an especially difficult problem, since not only is it highly localized but it can occur in environments that are merely mildly corrosive to the material. The damaging concentration of the harmful ions in that environment may be quite small and difficult to detect and, even in the absence of applied stress, residual stresses in a structure can often be of a sufficiently high level to cause SCC and failure in service.
In a given situation the time of exposure needed to cause SCC failure depends on the stress intensity at any pre-existing or developed crack tip. The concentration of stress at the tip of a sharp crack or flaw can be quantified in terms of the Stress Intensity Factor, K1. It determines the growth rate of SCC cracks for a specific alloy environment combination. Catastrophic failure of a component will occur when this factor reaches a critical value, the Fracture toughness of the material, K1C. This enables the determination of allowable defect size in design to avoid failure under given loading conditions.”
Your fine old Wade & Butcher has likely been exposed to over 100 years of corrosive influences and in all probability the stress induced in the polishing & honing process was sufficient to begin the failure.

There is obviously no way of telling how far the micro-cracking permeates the metal or how much will have to be removed to find that perfect edge, but I wish you good luck!

pretty cool. caustic cracking. As I was reading along I thought corrosion could have been hiding in micro cracks. SCC is different from regular ole corrosion?
Are these effects more a concern for bridge engineers? If a pitted razor rests for too long with a bar of lye soap; will that cause it? We need to capture these ions and use them to sharpen with

At Bart's magnification wouldn't we be able to detect discoloration, possibly?

I guess not if the ions are banging away on the inside? something like that?

Originally Posted by kevint

At Bart's magnification wouldn't we be able to detect discoloration, possibly?

I've made another picture.
You guys are gonna have to take my word for it, but the edge was flawless before the test shave. Every damage you see was caused by a few swipes WTG.
The visual shows no discoloration. My picture does, but it's caused by my small led light source and the fact that I shoot those pictures through the eye piece of the scope. Magnification of this picture is 30X.
I initially planned to hone a bit further tonight, but I haven't found the courage yet.

Thanks,
Bart.

on the other side- are those chips or curls?

There's that 8tape bevel line.
It's obvious now that you say 30x. Of course. I think you'd need a bit higher be sure there is no visible corrosion.

I can see those pits though

Firstly Bart can I say wow. The improvement on what was there when it left me is huge and immediately obvious!

Secondly a thought occured to me. Is there any chance that what looks like bog standard pitting on the actual blade is in fact something much deeper? Something that might go all the way to the core? That might explain why 1 shave WTG has brought out what appear to be a series of small indentations or semi-circles in the edge?

Just a thought...