How to Mix Thinner With Base Coat

Updated February 21, 2017

Mixing base coat paint with thinner is a process that can be beneficial for a number of different applications. When painting cars, trucks or motorcycles, mixing the base coat with thinner can help create a smoother finish. Painters of ceramic figurines and model aeroplanes find that mixing their base coat with thinner helps with shading and shadowing for a more realistic product. Thinned base coats are also often used for airbrushed paint projects.

Ventilate your work area by opening all windows and doors. Cover your work space with a canvas or plastic dropcloth and put on a respirator mask.

Pour your base coat paint into a larger bucket to give you room for mixing. A clean 5-gallon bucket works well.

Stir the base coat paint for three minutes with a wooden paint stick. This step is especially important if the paint has been sitting on a shelf for a while. After the three minutes are up, continue mixing if the paint doesn't have a uniform colour or consistency.

Add paint thinner in a 1:1 ratio to the bucket of base coat paint. For example, if you have 1 quart of base coat paint, add 1 quart of paint thinner. Use a measuring cup to ensure that your measurements are correct.

Use your wooden paint stick to stir the paint thinner and base coat until the mixture is uniformly combined.

Let the paint on your paint stick dry completely before you dispose of it.


Use a tight-fitting lid for your bucket to keep the paint from drying out between jobs. Don't feel compelled to buy a certain brand of paint thinner to match the brand of base coat. Any brand of paint thinner will work.


Don't inhale paint thinner fumes. Keep children out of the room when working with paint thinner.

Things You'll Need

  • Dropcloth
  • Respirator mask
  • Base coat paint
  • Paint thinner
  • 5-gallon bucket
  • Paint stick
  • Measuring cup
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About the Author

Rachel Terry has a Bachelor of Arts in English from Brigham Young University. She has been a freelance writer since 1998, authoring literary study guides, as well as articles and essays.