How to Thin Wood Stain? (Oil-based & Water-based Stain)

If the wood stain is too thick, you must thin it. Thinning or diluting wood stain before application makes the painting process easier. Thinning also helps to eliminate bumps and ridges in the finish. So, how to thin wood stain?

To thin wood stain, you need to pick a paint thinner first. For water-based wood stain, use water or a water-based paint thinner. For oil-based wood stain, use oil-based paint thinner or mineral spirits. For lacquer stains, use lacquer thinner.

Measure and add the right amount of thinner to the wood stain. After that, stir the mixture until you have an even consistency, and test the stain to see if it’s thinned.

But that’s not all. There is more to know about thinning wood stains, and this post digs right into the topic. So let’s dive in.

Thinning Wood Stain: Things To Know

You can dilute wood stain by using the right amount and type of paint thinner. You must thin wood stain by a ratio of 1:4 (1 part paint thinner and 4 parts wood stain). 

You can also thin wood stain by adding 2 tablespoons of paint thinner for every pint of wood stain. For varnish stains, you need more paint thinner because varnishes are thicker than regular stains.

Thinning wood stains for large-scale tasks like staining garage doors or decks can be a bit daunting. This is because it will be difficult and time-consuming to thin large amounts of stain to achieve the same color shade.

To thin stain for a sprayer, you must add more paint thinner. That’s because spray guns have a tiny nozzle that doesn’t accept thick wood stains. So, you need to thin wood stain more than usual. 

However, if you want to apply the wood stain with a paintbrush, you don’t have to thin the stain as much. This is because paintbrushes can handle thick paints.

Contrary to popular opinion, thinning wood stain will not affect the stain’s color as long as you thin the stain with the right amount of paint thinner. The color will only be affected if you over-thin the wood stain.

Reasons For Thinning Wood Stain

You should dilute wood stain for the following reasons:

  • Thinning helps the stain to become lighter, so it’s easier to apply.
  • Thinning wood stain makes the stain dry faster
  • Thinning wood stain makes it easier to spray the wood stain.
  • Thinning wood stain helps to achieve a smooth and fine finish.

How To Thin Wood Stain?

Thinning wood stain isn’t a difficult task, but it requires a bit of calculation to prevent you from over-thinning the wood stain. 

You also need a few tools, here they are:

  • A paint bucket
  • Wood stain
  • A plastic funnel
  • Paint thinner
  • A paint mixer or turning stick

1. Open The Paint Container

Open The Paint Container

Wood stains come in air-tight containers, open the lid to access the stain.

If the wood stain comes in a spray can, cut an opening at the top of the spray to gain access to the paint. Without opening the stain’s container, you can’t thin it.

2. Pour Out The Wood Stain

Pour Out The Wood Stain

You must pour the wood stain into another paint bucket. However, before doing that, you must clean the paint bucket. This is to remove paint residue, dust, and debris inside the paint bucket that can ruin the wood stain.

To clean the paint bucket, use a rag. Tough stains can be cleaned using warm soapy water or rubbing alcohol.

Once the paint bucket is clean, pour the wood stain into the bucket. You don’t have to pour all the wood stain if you don’t plan to use all of it.

3. Measure and Add The Paint Thinner

Measure and Add The Paint Thinner

To dilute wood stain, you must use the right type (and amount) of paint thinner.

To thin water-based stain, use water. To thin oil-based stain, use mineral spirits. To thin lacquer or gel stain, use lacquer thinner. 

If you want to spray the wood stain, use a ratio of 1:2 (1 part paint thinner, 2 parts wood stain). If you want to use a paintbrush, use a ratio of 1:4 (1 part paint thinner, 4 parts wood stain). 

4. Stir The Mixture

Stir The Mixture

Next, stir the mixture to get an even flow and color. You can stir the mixture by using a turning stick or paint mixer. The paint mixer will be faster and produce better results. 

If you use a turning stick, don’t stir too fast or hard as it can cause air pockets to trap in the stain coating. Instead, move the turning stick in a figure of 8 motion. The turning stick must be long enough to reach the bottom of the paint bucket. This ensures that the wood stain at the bottom is also thinned. 

If you are thinning lacquer stain, don’t stir too much as this can cause bubbles to form inside the lacquer wood stain.

To mix lacquer stain, pour the paint thinner and stain from bucket to bucket. To do this, put the lacquer stain in one bucket and the paint thinner (or mineral spirits) in another. Then, mix both of them by pouring from one bucket to another repeatedly. This limits the possibility of bubbles in lacquer stain. 

5. Test The Wood Stain

Test The Wood Stain

Next, test the thinned wood stain on cardboard or other dispensable material. If the stain has a good flow, goes on well, and dries properly, you have successfully thinned the wood stain. 

Products To Use To Thin Wood Stain

What Can You Use To Thin Wood Stain

You can use both natural and synthetic solvents to thin wood stain. The choice of thinner depends on the type of wood stain you have, whether water-based or oil-based. Let’s check out some popular paint thinners and see if you can use them to thin wood stains.


You can dilute the water-based wood stain with water. That’s because water-based stain uses water as its solvent and can be thinned with water. The more water you add, the thinner the wood stain gets. 

However, you shouldn’t use water to thin oil-based or lacquer stains. That’s because these stains use oils and resins as their solvent and won’t dissolve well in water. If you thin oil-based wood stain with water, you will ruin the wood stain follow, consistency, and color.

Paint Thinner

Oil-based and lacquer wood stains can be thinned with paint thinner. To thin water-based wood stain with paint thinner, you must use a water-based paint thinner.

Paint thinners are gotten from a combination of turpentine, mineral spirits, acetone, xylene, naphtha, and toluene. These compounds are not compatible with water-based wood stains, but you can use them to thin oil-based wood stains and lacquer stains.

Mineral Spirits

You can use mineral spirits to thin lacquer and oil-based wood stains. But, you can’t thin water-based wood stain with mineral spirits due to mineral spirits’ oily and chemical-based formula.

Mineral spirits can be used to thin gel stains too. Gel stain isn’t easy to thin because it has a thick consistency. To thin gel stain, you must use a strong paint thinner such as mineral spirits to dissolve and dilute the gel. Instead of mineral spirits, you can also use varsol because it contains mineral spirits (although not in its pure form).


Acetone can thin wood stain but isn’t the best choice. You should only use the solvent if you have experience in using it. If you don’t use it properly, you can ruin the wood stain instead of thinning it. Acetone isn’t a stain thinner; it’s a stain remover.

Acetone is a key ingredient in paint-removing solvents, as such, it can separate the binder from the paint particles. This makes it difficult for the paint to stick properly.

You should only use acetone to clean paint equipment and work area after staining wood. This way, you are at limited risk of ruining the wood stain.

Does Thinning Stain Change Its Color?

Thinning wood stain doesn’t make the color lighter but makes the paint flow or consistency lighter. The color isn’t affected when you thin a stain with the right amount of paint thinner. The color shade will only get lighter or off if you over-thin the wood stain.

However, when you thin stain, the flow is affected. This means that thick wood stain will become lighter or less thick.

This is because when you thin wood stain, the amount of solvent in the stain increases. In other words, the solvent to stain ratio increases in favor of the solvent. This makes the paint flow lighter.

Final Words

Overall, wood stain can be thinned, but you must use the right type of stain thinner to prevent ruining the stain’s consistency and color. Asides from that, you must add the right amount of paint thinner to the wood stain, so you don’t wood-thin the wood stain.

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