A straight razor should be stropped before each use, and some people advocate stropping again half-way through a shave. Strops come in various different forms but there are two basic types, hanging strops and paddle strops. Hanging strops are essentially flexible pieces of leather with a handle at one end and a ring at the other which is attached to a hook. Some hanging strops can be used on both sides, others only on one side. The strop pictured below is a hanging strop made from high-quality cowhide. The round ring is used to hang the strop on a coat hook or similar, then the strop is pulled taut by grasping the handle at the other end. The razor is stroked from the bottom to the top and back again, spine leading and edge trailing, at right-angles to the length of the strop. At the end of each stroke the blade is not lifted from the strop but rolled around the axis of the spine (back) of the blade before commencing the next stroke.
Paddle strops are more rigid than hanging strops and are simply held by one hand, they do not need to be attached to a hook. Paddle strops come in different forms. For example, some are completely rigid, some have a degree of spring in them and with others the degree of tension in the strop can be adjusted.
A basic paddle strops is typically more expensive than a basic hanging strop but beginners should consider paying a little extra as they may well find it easier to use a paddle strop, especially one of the extra wide paddle strops which can take the whole length of the blade.
You've maybe seen old films where barbers strop blades like they were buttering bread. This is fine if you want a blunt edge! The rolling action takes a little getting used to but take it slowly and with a little practice will soon have you stropping like a pro. You don't need to apply much pressure but ensure that the back and edge of the blade keep in contact with the strop at all times. About 20-30 strokes should be enough, with last few using the lightest contact possible.
While a simple bare leather strop is fine to start with, the exercise can be greatly enhanced by the use of pastes, as demonstrated in this video.
Strop pastes have been used for many years to enhance the benefits of stropping and are usually made up from iron oxide, chromium oxide or graphite in a 'carrier' to emulsify them. Spread on a strop they were an aid to finishing an edge, the coarser pastes being used first, followed by the finer pastes (similar to hones). The problem with using old-type pastes is that the steel being used in straight razor blades has, over the years, become ever-harder until a point was reached where the steel was harder than the paste supposed to be polishing it – in other words, a waste of time!
Traditional pastes are fine for vintage razors but for new steels with their extra-hard composition diamond pastes are ideal, as diamond is of course far harder than the hardest steel ever made. The diamond particles used in our (and other) pastes are by-products of the world diamond industry, the so-called 'industrial-grade' diamonds unsuited to gem use. These are ground and crushed to a fine powder and specified particle size – from 1/10 micron (one ten-millionth of a metre) to 100 microns or more. Here it is worth pointing out that cheap diamond pastes are low-priced generally due to the fact that the particle size is not strictly regulated, and indeed for some applications this is not a problem. However, for sharpening the ultra-fine edge of a razor it is essential that when 1-micron paste (for example) is being used there aren't chunks of 3 or 4 micron in there as well. The pastes we supply are tightly controlled as to particle size and have a higher particle density than most, hence their 'thickness'. The carrier paste used is both water and oil-soluble, making for easy cleaning and helping to reduce cross-contamination when compared with a pure oil base.
We also recommend the occasional use of a chromium paste prior to finishing as this helps ensure a smooth edge and a fine shave.
A user's experience of using Thiers-Issard diamond pastes for the first time may be found at Straight Razor place here: