Many years ago, I bought a marbleize kit to paint a table, and the results were surprisingly good. Equally surprising was how simple the kit was, so I will reproduce the steps here.
The items you need are:
- 4 colors of paint: black, gray, dark green, and white (In my case, I used black spray paint, and acrylic for the other colors. The type of paint doesn't seem to matter.)
- A regular sponge
- A feather (You can buy these at crafts stores, or you can used a twisted up sheet of paper. This is used to paint "veins" on the surface, as you need an uneven brush stroke.)
- Two paper plates to stage the paints
Step 1: Paint the Base Coat
First, paint the surface to be marbleized completely black. Of course, it's ideal if the surface is glass-like smooth, so if it's not, first use a filling agent like sanding sealer or wood filler to make the surface smooth. Even if the surface isn't smooth, the effect is still quite nice.
Step 2: Dab on the Contrasting Colors
After the black paint dries, put swirls of gray and green paint on a plate. You can vary the look of the marble by how tight the swirls are. In the attached picture, I used a fairly tight swirl, but a much looser swirl will also give a good effect.
If your sponge is new and hard, dampen it with water to soften it. Wring out all water to make it as dry as possible. Now that it's soft, dip it firmly into the swirled paint, then lightly dab the sponge straight down onto the black surface, only once per dabbed area. Keep dabbing away on the entire surface, dipping into the plate for more paint as needed. Before each dab, rotate the sponge slightly to the left or right to give a more random appearance to the overall pattern. Another way to modify the marbleize effect is to first cut out pieces of the sponge surface with scissors to create larger paint gaps on the surface. In this instructable, I used the sponge as is with no pieces cut out.
Step 3: Add Marble Veins
After the gray and green paint dries, you can add "veins" to the marble. Pour some white paint onto a plate, and lightly dip an edge of the feather into the paint. As mentioned, you can also use a twisted up piece of paper instead of a feather. Dab the paint onto the surface in a series of "tree branch" patterns. Be sure to lightly dab the feather in the paint, and lightly dab it onto the surface, as you don't want the veins to be too heavy. As you can see, one of the vein patterns in my marble surface was a bit too thick, so you should be careful about how much paint you pick up with the feature.
Step 4: Add a Custom Touch
You can even be creative/silly and create specific patterns with the veins.
After this dries, you can coat the surface with a clear gloss to protect the paint. Enjoy!