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Slick Coat

A Slick Coat is a “grease”  coat applied to a surface in preparation for a Glazing Medium application.  A slick coat is made of a clear solution and is usually applied with a roller, sponge, mist spray, or rag.



The purpose of greasing the surface is to allow the next layer to be moved and manipulated easier and stay open longer.  Adding a greasy slick coat before a veining step (with crystallization) can allow for better blending into the previous step.

Most commonly, a slick coat is used on large or sensitive surfaces or substates.  However, as seen in a previous post about red griotte marble, a slick coat was used in the activation step of a faux marble.

When the previous coat is absorbent, the water-based glaze in the next layer will be sucked up at a faster rate than a non-absorbent surface.   A chalky surface when covered with a glazing medium, for instance, dries at an increased rate and therefore has a shorter open time for a decorative finish.   This type of surface would be absorbent and difficult to work with.

Some absorbent surfaces/substrates are: 

  • Flat or satin paint
  • Applied textures
  • Plaster
  • Canvas
  • Raw wood (when staining over a light wood, use a stain conditioner as a slick coat).


The downside of using a slick coat is that it’s an extra step.  Also, the curing time could be extended and prevent a quick finish of the final steps.


First, step is to know the surface material.  Test the absorbency of your surface area using a wet sponge and wipe off an area.  If the color of the substrate turns lighter or darker or changes colors once the water has evaporated, you know there is a transfer of moisture.  A chalky surface is difficult to work with and will need a slick coat applied prior to your glaze.  Mix and apply your slick coat in the manner below.

FOR WATER-BASED MEDIUMS:  A slick coat for water applications could consist of 100% water (perhaps misted or sponged onto the surface).   More often though it’s 2 parts water to 1 part Glazing Medium that will create a slick coat that will not only fight the absorption rate but nourish the surface.

Mix and apply your slick coat using a roller, sponge, mist spray, or rag.  It is important to note that a water-based slick coat should only be used if the next layer is an acrylic Glazing Medium.  

After applying the slick coat above, the water-based glazing medium in the next layer will be absorbed by the surface below at a slower rate.

FOR OIL-BASED MEDIUMS:  If using oil glazing medium on the next layer, a slick coat of 50% linseed oil, 50% turpentine, and a touch of Japan drier is applied.