How to Thicken Paint

When painting with watercolors, you add water to make the pigment thinner and more transparent. If you want a thicker, more vibrant paint, simply use more paint and add less water. To get an even thicker paint that flows well and creates a brilliant color, try a watercolor medium. Watercolor medium allows you to mix colors smoothly and will also extend your drying time.

Tempera paints, often used in schools, are mixed with water like watercolors before use. To get a thicker paint with powdered tempera, simply add more pigment to your mixture. If you'd like something even thicker, try mixing in a touch of a paint-thickening agent you probably have around the house:

• Flour
  
• Cornstarch
  
• Salt
  
• Sugar
  
• Sand
  
• Sawdust
  

Some of them, like flour and cornstarch, will give a smoother texture, while sand and salt will result in a coarser medium. It should be noted that Rembrandt thickened his paints with flour, so you're in good company if you choose this method.

Like watercolors, acrylic paints are used by adding water before applying the pigment to the canvas, so the simplest way to get a thicker paint is to use more color and add less water.

You can also add numerous acrylic mediums to your paint to get a thicker or more texturized result. Use a gel medium to thicken paint -- choose gloss or matte -- depending on how shiny you want the paint. This paste-like gel enhances the adhesion and thickens your paint so the brush strokes show in your work, making it ideal for impasto techniques.

For an even thicker paint, use a modeling paste or molding paste. This makes the paint so thick that you can sculpt to create three-dimensional paint, creating a high-relief piece.

Painting with oil paints usually involves thinning the paint with turpentine or mineral spirits first, so again, getting a thicker pigment simply requires adding more paint and less thinner.

You can also use stand oil instead of turpentine to mix your paints, which will thicken the paint, slow the drying time and add a glossy finish. If you like the gloss but want to speed up the drying time, several other oil painting mediums are available to thicken oil paint, such as alkyd gel medium and alkyd butter. Alkyd is a resin with an alcohol base that increases the glossiness and drying rate of the paint.

Beeswax can be mixed with odorless mineral spirits and then added to your oil paints to create a thicker paint that also has a matte finish. A premixed version is called cold wax medium. If you don't like the matte finish, you can also add an alkyd medium to the cold wax to increase the shine.

When working with latex paints to paint a wall or mural, several methods can be used to make the paint thicker:

• Evaporation
  
• Hydroxyethyl cellulose (HEC)
  
• Joint compound
  
• Household thickening agents

Exposing latex paint to the air lets the water evaporate, and the paint become thicker. Open the can of paint in a well-ventilated area and stir the paint thoroughly. Check it every hour, stirring it again each time, until it reaches the consistency you want. Do not allow the paint to over-dry.

Hydroxyethyl cellulose is a thickener used for interior and exterior latex paints. It's compatible with a wide range of paint ingredients, applies with brush or roller, and it doesn't affect the integrity of the color. First create a slurry by mixing 6 parts water to 1 part HEC. Wait between 5 to 30 minutes for it to thicken. Then pour this mixture slowly into the paint, stirring well.

If you're looking for a more texturized consistency, you can add drywall joint compound to latex paint. Add a little bit of the compound to the can of paint and stir it completely. Continue adding just a little compound at a time and stirring thoroughly until it becomes the thickness you desire.

If you're in a pinch and need to thicken your latex paint right away, experiment with the same household thickening agents that can be used for tempera paints: flour, cornstarch, salt, sugar, sand or sawdust.