There are plenty of ways to polish clay, this is just one I put together for this video, but the concepts are the same for other polished plasters, like tadelakt.
This technique is not suited for wet areas, such as showers or floors. It is only water resistant, not waterproof.

Plaster mixes:
These mixes vary greatly depending on your substrate, weather, clay, sand, and application. And a test should be made first sampling everything. 

First mix fill, or base coat:
1/8 screened clay  1.25 gal
1/8 screened sand 2.5 gal
Water 0.75 gal
This layer is just to level your base, if your wall is relatively level already you can skip this coatlayer. 

Base layer for polish:
Clay 0.5 gal
Marble sand 1 gal
Water 0.5 gal
This is the main layer, and most of what makes up the finish. As mentioned in the video, glue can add strength and prevent delaminates while applying the cream layer, also this layer could be applied in two layers if it's easier. 

Cream mix, or clay slip:
Clay 1 cup
Water 3/4 cup
This layer is for filling small pores, and adding clay to the surface, which is what makes it shiny.

Oil is what starts to seal, and harden the clay.
Sunnyside Corp. 87332 Raw Linseed Oil:
https://amzn.to/2PEpoe9

Wax does the same, and gives the final shine. 
https://www.greenbuildingsupply.com/A...

Japanese trowels:

https://amzn.to/2VxOOQ4

http://www.japanesetrowels.com/
240mm rectangular blue steel,
240mm Flexible stainless steel

http://japaneseplastering.com/japanes...
240mm rectangular blue steel,
240mm Flexible stainless steel

Other Tools

Mixing paddle for drill:
https://amzn.to/2GVuNdZ

HVLP Gun:
https://amzn.to/2XSvGcW

Some of the above links are affiliate links, which means I receive a small commission with each sale at no extra cost to you.

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