Great question David!
So, absolute basics first. There are four main types of knot hairs used: Boar, Badger, Horse and Synthetic. The three you listed above are all types of synthetic knots. I'll get to the different types of each below. These are also generalities, for the most part.
1.
Natural hair brushes absorb water and should be soaked prior to use to avoid breaking the hairs. They also release water gradually throughout the lathering process, and thus require less water added throughout the lathering process compared to their synthetic counterparts. They also retain heat better, as a general rule. Prices for natural hair brushes can range from under $10 to well over $200 depending on the knot type and handle.
2.
Synthetic brushes are made of nylon/plastic, and do not need to be soaked prior to use. Instead of absorbing water, they trap water between the bristles, so when lathering and they are splayed out, water is dumped out at once rather than gradually added as you see with natural hair brushes. They will also hold less heat for the most part. Synthetic brushes range from just over $10 to $25-30 for commercially available brushes to over $100 for custom jobs. (mostly based upon the handles, not the knots.)
Now, that's the absolute basics...let's get a little deeper into this.
a.
Boar brushes - For the most part, the least expensive type of natural hair brushes. They will start out stiff and scratchy at first, but once the hair starts to split at the tips, (i.e. breaks in), they tend to become extremely soft during use. Some people tend to prefer boar brushes to other types of natural hair brushes.
b.
Horse Hair brushes - I honestly do not have any experience with horse hair, but those who do like them, though not necessarily prefer them to other types of natural hair brushes. They are about the same price, maybe slightly more expensive than the average boar brush.
c.
Badger Hair Brushes - This is where you start to get into the black hole of hair grades. Due to the amount of manufacturers out there who have their own grade of "premium" badger hair, there really isn't a standardized system for trying to figure out what each descriptor means. Below is a list of a few of the more popular grades you'll see used:
- 1. Two-Band* - characterized by the presence of only two colors to the hair...a darker "band" emanating from the handle with a lighter "band" at the tips. Typical characteristics are soft tips, decent backbone.
- 2. Three-band* - Instead of just two bands visible, the hair on these knots are mostly white, with a darker band about halfway between the base and tips. Softer tips than the 2-band, typically, but not as much backbone.
- 3. Silvertip* - Generally a 3-band knot, these are considered to have the softest tips of any of the badger hair knots.
- 4. Manchurian* - Typically a 2-band knot, they have thicker hair shafts which give more backbone, but softer tips than the normal 2-band finest.
- 5. Finest* - See the description of the 2-band...a good mix of backbone and soft tips, typically. Normally a 2-band knot.
- 6. Best* - This is a grade used by Simpson to describe their version of a 3-band silvertip equivalent of a finest grade knot elsewhere.
- 7. Super* - This is an even more dense, softer tipped version of the best badger by Simpson.
- 8. Pure Badger - a mix of badger hair qualities with the tips trimmed to shape. Typified by a uniform or mixed color with no defined banding on the hairs. Can also be referred to as Black Badger.
* These grades typically are NOT trimmed at the tips. the shape of the knot is created by putting the hairs in a form and tying/gluing the knot together from there. Pure and Black badger knots are trimmed at the tips and can give a scratchy sensation to the face.
A few other terms that you'll see when reading about shaving brush knots...
Density: the amount of hair packed into the knot. The more dense a knot, the more likely it will be to hold onto the lather.
Backbone: the resiliency of the hair to bending. The more stiff the hair is, the more difficult it is to "splay".
Gel-Tips: the thinner the tips are, the more they will have a tendency to clump together when wet, and create a gel-like sensation on the face.
Loft: the distance from the socket of the handle to the tip of the knot.
Bulb: The shape of the tips of the knot forming almost a half circle.
Fan: The shape of the tips of the knot forming a "fan". Some people say this is more prefered for face lathering, while others prefer bulbs. My personal opinion is that I enjoy each for what they are and use both shapes for both.
Presence: Ken from Paladin uses this to describe a knot that has good backbone, density and soft tips. The better the presence, the better each of these qualities are.
Scritch: Not to be confused with being scratchy, in my eyes it is closer to being scrubby....hard to really describe the difference between scritch, scratch, and scrub.
Flowthrough: The ease with which a knot releases lather
Synthetics - So you'll see different types of synthetic knots out on the market. For the most part, there are only five main types.
1 -
Tuxedo knots: black fibers with white tips. They tend to have decent backbone and VERY soft tips.
2 -
Cashmere knots: all blonde hairs that are extremely fine, exhibit not very much backbone, but are extraordinarily soft.
3 -
Plissoft - Classic looking synthetic knots. The original attempt at a synthetic knot attempting to look like a natural hair. Softer at the tips than natural hair, but the latest generation of hair, once splayed, can be a bit more scritchy than their natural hair counterparts. (all of these three have crimped hairs along the length causing this sensation)
4 -
Muhle synthetic - A little different type of synthetic knot that I actually don't have experience with, but has a large following. A bit more expensive than others, but are supposedly as soft as the tuxedo knots with better backbone.
5 -
BOSS/AMAK Gamechanger - All black/brown knots for the most part with black tips. Not quite as soft as the Tuxedo or Cashmere knots, but better backbone. My most reliable lather maker out of these.
additional ones you might see
6 -
Mother Lode knots - These are actually make-up brushes...red fibers with white tips, they are extremely dense knots with very thin fibers. From what I've read, they are lather hogs and have problems with flowthrough. Very little backbone in these knots.
7 -
Ghost knots - pure white knots. Supposedly soft at the tips with incredible backbone. Has been accused of being way to scrubby for many people.
8 - Various colored tuxedo knots...blood knots, timberwolf knots, greywolf knots...these are all just color variants of the tuxedo knot.
