Like most people with nice dress/business shoes I worry about water damage to my nice shoes in the late Fall, Winter and early Spring.

There are a number of water resistant solutions on the market, but most are for heavy leather like boots, or inverted leather like suede. These solutions typically include either heavy wax, heavy oil, or synthetic chemicals like silicone, or other toxic smelling chemicals.

I could not find an all-natural, non-toxic water resistant solution that was light enough not to smother my thinner dress/business shoe leather. I received recommendations to use mink oil and neatsfoot oil, but the amount I would have to use to make the leather water resistant would smother the leather, and potentially stain the leather.

I could have also went with galoshes, but I didn’t want to damage or hide the shine of my shoes.



There has currently only been three ways to add water resistance to leather shoes:

Seal the leather from the outside (heavy wax, silicone spray, goulashes and so on.) Fill the leather fiber with heavy oil (or other stuffing agents) so the water can’t penetrate the leather. This is done by stuffing the oils and other agents between the collagen fiber bundles (as you rub the oils in). A combination of one and two (usually silicone or other synthetic chemicals)

Since I had already created the all-natural GlenKaren shoe polish line, I decided to see what I could do to make that polish more water resistant.

The beeswax and carnauba wax in the polish offer some minimal amount of water resistance (as most shoe polishes containing wax do), but I could not just increase the amount of wax because it would make the polish too thick and sticky and smother the leather from the outside.

I could increase the amount of coconut oil, but coconut oil is a highly saturated fat, and if not used in moderation could smother the leather from the inside.

I had to figure out a way to protect the individual collagen protein fibrils from water while still keeping them lubricated with oil, and not clogging the collagen fiber bundles.

Below is an illustration of a piece of leather, in orders of magnitude, down to the atomic makeup of a collagen protein fibril:



To find a solution I had to extend my research further into how leather is made. I didn’t get into the animal husbandry aspect of how a baby calf is born, but I did do more extensive research on the steps of how leather is created in a tannery.

During a step called basification the pH levels of the leather are managed and the tannins are introduced which stabilize the leather and, along with the fatliquoring, keep it flexible and soft. In this process the tannins are bound to the collagen proteins through a process called protein binding.

A protective coating given to the collagen protein strands during the tanning process where the tannins and oils are hydrogen bonded to the collagen protein chains. Collagen’s high content of the amino acid hydroxyproline allows for significant cross-linking by hydrogen bonding within the helical structure. Tanning increases the spacing between protein chains in collagen from 10 to 17 angstroms, this additional space is filled with the hydrogen bonding the tannins (or chromium salts) and oils to the collagen. It is these bonded tannins and oils that increase the hydrothermal stability of the skin.

Using the idea of protein binding I decided to find a way to bind an all-natural, non-toxic solution to the individual protein fibrils. Borrowing from the tanning process where sodium bicarbonate (baking soda) is used to assist in protein binding, I just needed to find something with a similar chemical composition that would also be a water insulator for the collagen protein.

That is when I came across sodium bentonite (Bentonite is also known as Montmorillonite). A natural clay used in beauty face masks, wine purification, health food additive, pet food additive, kitty litter, and pond liners. It has a lot of uses, and come in a food grade powder form.



Sodium Bentonite has some very interesting characteristics:

Similar to sodium bicarbonate, sodium bentonite has a strong ionic charge that assists in the protein bonding.

Due to the platelet structure of sodium bicarbonate and its atomic pattern at the molecular level it actually attracts water molecules and binds them to the outer layer of the sodium bentonite molecules, while the inner layer is bonded to the protein molecule, thus creating a protective sheaf for the collagen protein fibril.

The platelet structure of the sodium bentonite actually expands to a degree as it is exposed to more water to create a tighter seal. Once the water evaporates the sodium bentonite contract back to its normal size. This is done at the molecular level so you wouldn’t see it happening, unless you poured a cup of sodium bentonite into a beaker and then added some water.

It is important to note that the sodium bentonite in the shoe polish will penetrate the leather with the oils, as well as stay on the surface with the wax, this allows for a double water barrier of sorts.

The amazing thing about sodium bentonite is that it only acts like a water repellant when exposed to water (even just one molecule of water), unlike wax or oils that must thoroughly coat or saturate the leather all the time to be effective. And, unlike oil, sodium bentonite cannot be flushed out by water (it can be removed with a cleaner like orange oil [GlenKaren Cleaner/Conditioner] or Saphir RenoMat).

If you have been looking for a water resistant shoe polish for your dress/business shoes and don’t want to use heavy waxes, oils, or toxic smelling chemicals please give the GlenKaren water repellant shoe polish a try. It is still made of the same all natural, non-toxic, ingredients, but with the inclusion of sodium bentonite.

The images below show a black Allen Edmond wholecut being sprayed with water, let sit for a period of time, then wiped off with a dry cotton cloth:



For more information on ordering please go to the GlenKaren Care Products web site.

As a side note: GlenKaren Care Products still produce the standard polish line without sodium bentonite as well.