How to thin wood stain

How to Thin Wood Stain: Easy Methods for Beginners

You have selected a striking stain for your bungalow or you have just finished sanding your gorgeous antique wooden furniture. Now you are all set to stain. Don't ruin your work with a thick stain. Too much thick material will create bumps, unevenness, and or ridges on the surface.

Thick stain can drive you mad. And if you are using a sprayer for applying, this madness will get out of control

After all that effort you have put into your project, why destroy it by a thick stain?

Choose a thinner stain or simply thin your stain yourself. But it is important to know how to thin stain with a right thinner and perfect ratio of it.

A thinner stain will also leave you in a problem. There are different stains and each one requires a special method with a specific thinning agent. Let us discuss the different thinning methods in detail.

Why do we need to thin stain?

There are many benefits of knowing how to thin a stain perfectly. A thinned stain can be easily applied by all means. On the contrary, a thick paint is very difficult to coat even if you are using a brush, sprayer, or a roller. You can get the uneven surface, traces, and more clogs in your sprayer.

It is true that you have to apply more layers of a thin stain than a thick one but will satisfy you with the smoothness of the surface. Thinning is a good technique to prevent your stain from drying quickly.

Sometimes after applying stain, we might wish that its color could be little light. A perfect tone of the color can be achieved by a thinner stain as it is applied by several coatings. One of the big advantages of using a thinner stain is that it can save you money.

How we can do that? Adding more liquid or thinner in the stain will also increase its quantity. Though it needs more coatings a diluted stain will also cover more area by spreading. Always identify the right stain and use the required quantity to enjoy all these benefits.

How to thin wood stain: Different Method Discussed

1. Thinning Stain with Mineral spirits

Thinning Stain with Mineral Spirits

How to thin an oil-based stain? Many oil-based thinners contain mineral spirits as a thinning agent. A mineral spirit in a wood stain is called as "petroleum distillates". Many varnish-based and polyurethane-based stains also contain mineral spirits.

For thinning purposes, try to add more mineral spirit to it. The ratio of thinner to stain is not crucial. While applying stain with a rag, try to add around 50% of thinner in it. However, this percentage differs for various stains.

For example, varnish stains are thicker than oil-based stains. They require more amount of mineral spirits.

Be aware that you will have to apply more coats of a more diluted stain. This is because a greater number of thinning agents will reduce the measure of stain in it.

It is recommended to add thinner in a small amount while mixing it well in a solution.

Always test a stain before adding more thinner into it. Too much mineral spirit will only make the color lighter than your desired results. An ideal mixing is 3-4 parts stain to a 1-part mineral spirit.

If you are using a sprayer to apply stains, try to use less amount of mineral spirit for dilution. Too much thinner in a stain makes it difficult to apply through the spray gun. It only results in dripping and excess wiping during satin application.

Mineral spirit is less toxic than many other chemicals. But It is flammable. Its fumes are still poisonous and can cause skin-related issues. More exposure to it can also result in nervous system damage. Always wear safety glasses and proper gloves before using it.

Mineral spirit is a bit expensive thinning agent and there are some alternatives for it. Always prefer mineral spirit over those alternatives as other thinning agents contain deadly chemicals.

The following are the thinning agents that can replace mineral spirit.

  • Varsol: It contains mineral spirit but not in pure form. It is also known as the white spirit.
  • Naphtha: It is a very flammable product and helps in speeding drying time. The main components of naphtha can be petroleum distillates, crude oil, and refined products.
  • Turpentine: Turpentine is best for thinning varnish-based stain it has a strong bitter smell and dries very slowly. It is more expensive than other solvents.
  • Paint Thinner: It also contains a less pure form of mineral spirit with chemicals like naphtha, acetone, glycol ethers, xylene, etc.

2. Dilute Wood Stain with Water

Water-based stains are commonly known as "latex Stains". Water is a thinning agent in these stains that are made up of water-compatible artificial resins. To make a more diluted solution of these stains, more water can be added to the solution.

The following materials are required for thinning water-based stains.

  • 18.9/5 gallons Liter Bucket.
  • Paint mixing sticks.
  • A big Funnel.

While using a pint of stains, add 2 tablespoons of water per pint. Never attempt to put in all water together. Use room temperature water. For better mixing of stain and water, you can also pour it from one bucket to another instead of using sticks.

Add all of your stains into a bucket. For each gallon mix 1/2 cup of water in it. With the help of a stick, stir mixture carefully. Now pour it through the funnel and check its viscosity. Viscosity indicates how thick or thin material is.

If your thinned mixture can flow freely through the funnel, then thinning of stain is successful. When the stain is not flowing smoothly and is blocking the pour, try to add another 1/8 cup of water for each gallon.

If by mistake you have added extra water in stain, your satin will become too thin to apply. To achieve its even consistency, start by adding 1/2 cup of stain in the bucket. Continue stirring to make a correct solution. Keep adding more paint until you get your ideal thinned stain.

Thinning latex stains require at least 4-5 coats while applying. Nonetheless, coats completely depend on how thin your water-based stain is! A standard thin latex stain will only need 2-3 coats.

To maintain the ratio in solution, try to cover your stain bucket with a lid after working on it. Uncover water-based stain will allow moisture evaporation and it will again become thicker. It is a good approach to keep stirring a latex stain to avoid more thickness in it.

Other than water, there are many other thinning agents available in the market for water-based stains. They are labeled as water thinning additives. Most of the manufacturers also advertise these thinning additives as a wood conditioner.

Those products can be effective but water is the best thinning stuff to dilute any kind of water-based finish.

3. Thinning Stains with Lacquer

Thinning Stains with Lacquer

For any kind of lacquer-based stain, use a lacquer thinner. A cellulose thinner is another name used for it. This kind of thinner is complex and contains much acetone with a low amount of aromatic solvents. They also consist of alkyl esters and aromatic hydrocarbons.

Lacquer thinners cannot be used for any stains other than lacquer-based. For thinning a lacquered stain, grab the following materials.

  • Spray gun
  • Lacquer Thinner
  • Stir Stick
  • Gloves/ Respirator

Put on your safety equipment including respirator before starting this work. Start diluting your stain by adding 1 or 2 ounces of thinner. Keep stirring and mixing the stain for at least 20 seconds.

For a big project of lacquer stain, transfer half of lacquer into a gallon can. Add 1 pint of thinner into it and stir it with mixing stick.

If you are applying lacquer with a spray gun, instead of stirring it with stick shake spray bottle strongly. After mixing it well, test it in a small portion and check its evenness. It should feel smooth and not extra runny. An even surface free of bumps indicates a perfect thinning stain.

If the mixture has become runnier, then add more lacquer stain in it. Always add a small quantity and test it before adding more amount. It is always recommended to use a lacquer thinner that is recommended by a lacquer manufacturer you are trying to thin.

Keep in mind that different lacquer thinners are made up of different diluting solvents. They are highly flammable materials. It is a good practice to keep them away from any heat source. Their fumes can be so deadly and poisonous that they can harm your nervous system.

Avoid thinning lacquer more than twice however it can be possible in some cases where the evaporation rate of lacquer is fast. Lacquer thinners are mostly sold as cleaning agents to clean brushes and other equipment.

Additional Tips for Getting Perfect Results

By keeping these tips in mind while thinning any kind of stain, you will be able to achieve a perfect outcome.

1. Identify your stain

Before selecting a thinner for your stain, know which type of stain you are using. You can check the ingredients listed on the stain container. Oil-based, water-based, lacquer-based, polyurethanes based all stains carry different dyes and solvents.

Oil-based stains mostly contain petroleum distillates known as mineral spirit. Varnish stains are more viscous than oil-based stains but they also have mineral spirit in them. Water-based stains are very different from oil and varnish stains.

One major difference is water stains use water as a solvent and are mostly partially transparent ones. Modern water stains label word latex on them.

A lacquer stain has a very strong odor and can be easily identified. This strong smell is because of xylene, toluene, and ketones present in them.

For thinning oil and varnish, use mineral spirit. Thinning of lacquer stains or non-grain raising stain can be done by lacquer thinners. It is obvious to use water for thinning water-based stain.

2. When to add Thinner?

To get perfect results, it is a useful tip to add thinner just before starting your staining project. Diluting and storing earlier may result in the thickening of the whole solution. This can because of evaporation.

All types of stains can be thinned again and again except for varnish stains. Try to add a small amount of thinner in stain and stir it thoroughly. It will help in dissolving all kinds of pigments into solution.

It is almost impossible to make a satin too thin because thinner will its color. Most stains are already thin enough to use through a sprayer. However, if you are thinning for a spray staining project, do not make it extra dilute. A more diluted stain will cause dripping and running while spraying.

3. Test the Stain

After adding a small quantity of thinner in stain, it is suggested to test it before any further increment. If you don't have any extra surface or material available for testing, try to test it on a very small portion.

With the help of this, you will become aware of stain texture and appearance. You can simply then add stain or thinner for your desired color. Repeat this process as many times as you want until you are completely satisfied.

4. Using Multiple Buckets

You may know this quotes; Don't Put All your Eggs in One Basket. Then you know what i mean about using multiple Buckets

For thinning purposes, always keep multiple buckets with you. This will help you in making the process speedier. You can use different buckets to mix stain with thinner by just pouring from one bucket to another.

Different extra buckets can also help you with storing any excess thinner, stain, or a thinned stain.


We are sure that you have can master thinning techniques after reading our useful guide on how to thin wood stain. The main thing to become a pro is to select right thinner for stain and suitable quantity of it. Always test it and add thinner in a small amount to reach uniformity.

Whether you are using oil-based, water-based, or a varnish stain, practice the above-mentioned tips for the best outcome. It is not a difficult task and just requires a little patience. Rushing work will only damage your stunning stain.


9 thoughts on “How to Thin Wood Stain: Easy Methods for Beginners”

  1. Thinning my oil based stain with paint thinner worked and gave me the desired color. But it was on a mantle beam. And o had to used probably 8:1 ratio of thinner to stain. Maybe even 10:1. There were no other colours that provided the cool dark brown colour that I wanted, but due to the wood and its age, applying the stain alone looked like black paint. My concern now is it’s flammability? Might seem like a silly question but I can’t seem to find an answer anywhere.

    1. Thanks for your query. 🙂
      Yes, an oil-based stain is flammable especially the used cloth. Please do not store them.
      Please try to get rid of them as soon as your work is done.

      1. Oh yes the rags are gone. My concern is the beam. If I painted on 10:1 ratio of paint thinner to stain, onto the beam (its outside right now until it dries because it stinks) – is that mantle dangerous now. Have I done a horrible thing that makes it now flammable (especially as a mantle over a wood burning fireplace insert). Or, does it eventually off gas enough to avoid the danger?

        Thanks in advance for any help. 🙂

        1. Thanks for clearing that up.
          It won’t be flammable if it is dried well.
          So, please make sure that you let it dry until the smell goes away. And then it will no longer be flammable.

  2. Nevin St-Onge

    I have a solid stain and I wanted to order semi transparent “oops”. Will adding water to the stain help with the transparency?

  3. I’ve used a Manns pine wood stain on some pine floorboards, some areas overlapped and have dried darker to the rest. The stain is water based, what would you recommend to use to help thin/lighten those areas?


    1. Hello Emily,

      Here are two methods to try:

      Method #1. First sand only the dark stain with 100-grit sandpaper. To blend in the dark spot and surrounding area, feather the edges with 150-grit sandpaper. Work along the grain and don’t push too hard. Once you sand out the stain, apply several light coats of the same stain you used to match the original finish. Feather the edges with #0000 super fine steel wool to blend with the surrounding wood.

      Method #2 While wearing rubber gloves, dip a brush into a bowl of bleach and apply it lightly and directly to the dark spot areas. Allow the bleach to sit for a few hours as the stain fades back to match the rest of the wood. Remove the bleach with a damp sponge, and apply vinegar to neutralize the wood and prevent further lightening. Let the wood dry and finish with stain.

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