Honing hot, shaving cold?

On another thread, I recently posted a suggestion that someone shave cold to reduce skin irritation. Another poster replied with this:

This is a good point. I have a friend who's father was a barber way back when and he tell me that his Dad only used cold water when giving a wet shave. Why? Because the cold water makes the steel contract, thus giving a keener, tighter edge to the blade. Hot water will make the steel expand, thickening the edge and dulling the blade. True or not, it works for me!!

So, I'm curious about a consensus: could that be a factor to the cold shave experience?

Better yet, would there be any benefit to warming up a blade prior to honing?

(oops, should have posted this in the Honing thread.)

I think any changes in the blade due to the temperature difference between hot and cold water are going to be so infinitesimally small you wouldn't notice them.

A lot of this stuff is in peoples minds where they tell themselves it's better this way rather than that way when in actual fact there's no real difference.

I remember someone swearing blind that holding his razor under running water made the shave better because the water gave a mild stropping effect.

I've played around with a load of different temperatures and I reckon the biggest difference comes from hotter water making better lather and soaking into the beard better.

Quote:

---

Originally Posted by Stubear

I remember someone swearing blind that holding his razor under running water made the shave better because the water gave a mild stropping effect.

---

Well, maybe if it was really hard water.

yea and if you put a straight under really hot tap water and then put it to your face guess what happens, it burns.

Holding the razor under the faucet will most certainly hone the edge in a most mild way...if you leave it there a few years.

An approximate thermal expansion coefficient for steel is 0.00000645 in/deg F. Using this generalization, a 3" razor will expand 0.00001935" per degree the temperature is raised. Say we go from 80 degrees room temp to 120 degree hot water. We have a delta T of 40, meaning that a 3" razor will expand 0.000774". A human hair is roughly 0.04" in diameter. So if you cover 40 degrees, your razor will be about 1/100th of a hair longer!

Thanks for the nitty-gritty, adbuett.

To bigspendur: I put one of those little on-demand water heaters in my camper and used it once for a midshave rinse. Yep, found a new kind of razor burn. I do like the near-boiling temp for a final cleaning rinse, though. You know the blade will be dry very soon.