How to Use Paint Thinner

Several cans of paint with the lids off.
What You'll Need
Clean bucket
Paint thinner
Wooden stick, spatula, or spoon
Empty paint cans

Paint starts to thicken when exposed to open air for a long time. However, this does not always mean that you have to throw away your old can in favor of buying a new one. The job of the paint thinner is to change the consistency of the paint so that it can be used easily and conveniently. So, save yourself money and materials by revitalizing too-thick paint with a little thinner.

Step 1 - Buy the Right Product

Each paint has corresponding thinner to use when trying to save it, and no two types can be mixed together. If you are using a vinyl paint, for example, then it is essential that you buy a vinyl paint thinner. Therefore, when going to your local home improvement center to make a purchase, always ensure that you are looking for a compatible product.

Step 2 - Add Paint Thinner

Pour the paint into a big vessel, and then add the thinner a little at a time. Your product should have instructions regarding how much to use, but it is always a good idea to proceed slowly, mixing until you get the right consistency. After all, you can always add more thinner, but you can't take any back out.

Never leave the paint thinner can open for too long, as it will evaporate. Also, to ensure that you do not stain yourself or your clothes, put on gloves and an apron before starting this process.

Remember that cold paint looks thick and may lure you to adding too much paint thinner. Always do this job at room temperature instead to prevent mistakes. Paint should actually always be kept at room temperature and not allowed to get too cold or too hot. In frigid climates, do not store paint in unheated areas and allow it to freeze. This can destroy it in a way that no amount of thinner can fix.

Tip: When storing oil-based paint, pour a very small amount of the appropriate thinner on the top of the can before closing the lid. This will prevent a solid skin top from developing.

Step 3 - Mix

Use a wooden stick, spatula, or spoon to stir the paint while you add the thinner. Stir gently and until everything is completely combined before you check your results. If not satisfied with the thickness, add a little more until you get what you want.

Do not depend solely on a paint stick to blend this mixture. Instead, use several empty gallon paint cans to pour paint and thinner back and forth to attain a uniform consistency. Again, use very small quantities to gradually achieve what you're looking for.

Step 4 - Change Thickness Based on Technique

Each kind of paint and painting method can require a different consistency, so make sure you know exactly what you need before starting. For instance, if you want to paint a large surface, an airbrush might be the best tool to use, and in this case, the paint consistency would need to be thin so it could be worked through the sprayer.

Step 5 - Coat the Desired Surface

Once you're finished mixing, use your choice of tool and start laying a coat on your surface. Check as you go that you're getting a full, even coverage with your thinned paint. Also, always apply at least two coats for the best look. Of course, you'll want to make sure the first coat is fully dry before adding another, so check the paint label for proper dry times.

Edward Kimble, professional painter and author of Interior House Painting Blog, contributed to this article.