Originally Posted by
English
I think you need to differentiate the pressure on the spine and on the razor edge.
How much pressure?
The pressure on the spine needs to tension the leather strop.
The pressure on the following edge needs to be enough to brush the leather nap smoothly.
So depending on how tightly you hold the strop, the more or less spine pressure will be needed. The blade is then effectively held at an angle that lets the edge brush the leather nap. As you go through the stropping, it's actually best to lighten the brushing action. Same as with honing.
You know when you have it stropping correctly, not by the sound particularly, but by watching the nap on the leather change shade as the edge brushes the nap. Its a bit like watching the water movement on a hone.
Watch the nap reflection on the strop as the razor edge passes over it.
I think that horse hide is the best strop because the nap is the finest. Its again a bit like the grit on a hone. The blade passes more quickly over a finer strop and some do not like the lack of resistance. They prefer to feel a pull. Cow hide does this better than horse hide, but it is not as fine a nap. Finally a really rough nap is on the canvas/cotton or linen which does something to the edge, but to be honest, I d'ont know what it is. I think it just cleans any oxidation off the blade before hitting the leather and thereby stops the leather getting dirty as quickly.
You can clearly see the nap changing shade on Seraphim's superb horse hide strop in his excellent video.