Thread: CBN strops.... a thought

Originally Posted by DoctorSaul

I got to disagree with you. Even in our house which is just about 25 years old, there is discernible flow and ripple in the glass windows. I've also noticed that church and synagogue stained glass windows show the same rippling effect in windows that are older than a few decades. I've also experienced glass plates, like microscope slides, that if allowed to sit on top of each other for a relatively long (short?) time, like a year or so, they tend to fuse together. I remember rummaging through a bunch of University castoffs that included glass coverslips and microscope slides that were in original boxes from the 1930's. They were completely fused together something like a brick of glass. So, I've seen ample evidence that glass does flow, slowly be it, but still quickly enough to see distinct macro changes in a few decades.... micro changes like was commented on regarding plate glass (see prior post) probably can be seen within months or years of the manufacture of the glass plate.

Sorry to continue the OT, just had to chime in here... as someone with a background in chemistry and currently researching in solid state materials science, I can add to what else has been said here - aside from anecdotes or personal experience, I can tell you the science says that glass will not flow over any kind of human (or even earth-age) timescale. The fusing you speak of can be explained otherwise. This is the reason that 1000+ year old Roman glass artifacts still exist, some in their original fine detail. To get glasses to flow you need to go above the glass-transition temperature.

Guys lets stay on topic here.

Originally Posted by ScienceGuy

Sorry to continue the OT, just had to chime in here... as someone with a background in chemistry and currently researching in solid state materials science, I can add to what else has been said here - aside from anecdotes or personal experience, I can tell you the science says that glass will not flow over any kind of human (or even earth-age) timescale. The fusing you speak of can be explained otherwise. This is the reason that 1000+ year old Roman glass artifacts still exist, some in their original fine detail. To get glasses to flow you need to go above the glass-transition temperature.

OK... I give up (but don't concede defeat...I could further back up my position, but it is off topic). Just as a clue, what do you think is happening when glass is heated to the point it becomes obviously molten and readily flows? Going down in temperature, at what temperature does this phenomena cease? or does it not cease? Keep in mind that you are not dealing with a crystalline material at any stage in the heating or cooling cycle, just an amorphous solid decreasing or increasing in viscosity with temperature.

Your thread. Derail it all you want... Won't help you learn anything about razors tho.

Originally Posted by onimaru55

Your thread. Derail it all you want... Won't help you learn anything about razors tho.

I'm really here to learn proven techniques on honing, and enjoy the camaraderie with people of similar interest. The question of whether glass is a viscous liquid that flows, or not, while interesting to me, is not really germane to learning honing techniques, and is apparently getting some posters upset with me. So, i don't think I'm "derailing" the topic, just trying to get back on topic.

Originally Posted by DoctorSaul

I'm really here to learn proven techniques on honing, and enjoy the camaraderie with people of similar interest. The question of whether glass is a viscous liquid that flows, or not, while interesting to me, is not really germane to learning honing techniques, and is apparently getting some posters upset with me. So, i don't think I'm "derailing" the topic, just trying to get back on topic.

IME it is not, but then again, I've had an awful lot of viscous liquid flow into glass, and then into me ...... and out ......... but to get back on topic ......... I like honing too.

Originally Posted by ScienceGuy

... This is the reason that 1000+ year old Roman glass artifacts still exist, some in their original fine detail. To get glasses to flow you need to go above the glass-transition temperature.

I can't resist responding.....

Heck, there are Roman glass artifacts that are over 2000 years old, and Greek glass objects in the same time realm, and pre-history glass formed from volcanos. The fact that old glass exists does not prove that glass does not flow, albeit slowly. Careful measurement would no doubt show the effect of gravity on the flow of the glass.

What glass transition temperature? Glass is an amorphous solid/liquid throughout a reasonable temperature range, there are no polymorphs, there are no crystalline structures, hence, there is no glass transition temperature until you get up to really high temperatures or really low temperatures (but that is a whole different story). If one plotted temperature vs viscosity of glass one would see, at temperatures where the glass is obviously molten and flows, that the relationship between temperature and viscosity is linear, hence can be extrapolated back down to room/ambient temperatures. There is a calculable viscosity of glass at room temperature, and that viscosity, be it very high, correlates well with the flow shift seen in old glass due to gravity. Interestingly, because of the amorphous nature of glass, it also does not have a detectable yield point, so glass flow just due to the force of gravity can occur without having to exceed any other flow force.

I have to say, I'm enjoying all this glass stuff. Not the barbs, but the technical parts of the discussion. I may have to read the MIT paper. I wonder if the MIT guy would enjoy wet shaving.

I have no experience with CBN. I thought I might be interested in trying it but I'm learning nothing about it in this thread. I'm not "upset" about the constant derailment of the topic, just bored with it.

How about melding the two? Has anyone tried fiberglass cloth as a stropping medium, albeit an itchy one?