Whether you're looking to achieve a quality finish with oil-based paints or varnishes, or you need a solution to clean your painting tools, Cromwell stock a comprehensive range of paint thinners, suited to your requirements. With leading brands like Bostik, Hammerite and Rust-oleum, you'll be sure to find the right thinners for your application.

What are paint thinners?

Paint thinners is the collective term for a group of solvents that are known for their ability to reduce viscosity in, and dissolve, oil-based coatings like paints and varnishes. This can aid with the painting application, for example, spray gun applications, or with cleaning painting equipment. There are several chemical compounds that make up paint thinners, each suitable for different types of paints and coatings.

Why paint thinners?

Paint thinners are a simple and ideal way of cleaning brushes to help with the removal of excess paint.

When to use pain thinners?

As well as being excellent when you want to speed up the cleaning process of brushes and rollers, paint thinner is also ideal for use when using exterior paint in high temperatures in order to slow down the drying process.

Types of paint thinners

There are many different types of paint thinners all suitable for different applications. The most common types are outlined below along with a brief snippet regarding their uses and benefits.

• Lacquer thinner - A strong combination of different solvents including acetone, xylene, toluene, butyl acetate and other chemicals. Lacquer thinners are best used for thinning topcoat paints and varnishes as opposed to cleaning as the strength of the thinner can damage materials like wool (found on paint rollers).

• Naphtha - Naphtha is ideal for thinning oil-based paints and sealants including enamel, varnish, and wood stains. However, it doesn't work well with water-based paints due to its petroleum-based origins. It has the added advantage of being fast drying and being less likely to cause separation in paints. It does however have the disadvantage of releasing toxic fumes, which can be a health hazard if inhaled.

• Xylene - Whilst usually an additional ingredient in other paint thinning compounds, xylene can be used solo to thin sealants like varnishes and stains. It can also be used to clean up paint stains and remove paint from painting equipment.

• White spirits - These paint thinners are primarily used for cleaning tasks. Although not strong enough to penetrate oil-based paints, it makes a good solution for cleaning up residues from water and latex-based paints. Its stability allows it to be mixed with other suitable thinners when diluting oil-based paints for application.

• Denatured alcohol - Alcohol based thinners are good for diluting water-based paints and shellac stains. They can also be used to clean painting equipment and have the added advantage of disinfecting them at the same time. Their drawback comes when used to thin oil-based substances as they don't yield the best results.

• Mineral spirits - Possibly the best thinner for oil-based paints and sealants out there and is very similar to turpentine in nature. However, the negatives come in the form of water-based paints as it cannot be used to dilute these types.

• Turpentine - Turpentine or turps for short has several uses, but it makes an effective agent for thinning oil-based paints as well as removing paint residue, oil-based and acrylics. It has a dozen other useful cleaning uses not all relating to paint, including being able to remove tar and tree sap. However, it shouldn't be used to thin water, latex or shellac-based coatings.

• Water - Yes water can be used as a paint thinner! However, water only works to thin latex, chalk, acrylic, and other water-based paints. Water should never be used to thin oil-based paints as it will ruin the paint.

Considerations when choosing a paint thinner

There are a couple of main considerations to ask yourself when choosing the right kind of paint thinner for your applications.

• Thinning or cleaning? - Some thinners work well for cleaning and some better as a thinner. An example of this is white spirits, which works better as a cleaner and only really works as an actual thinning agent when combined with other thinning chemicals. Make sure you pick a paint thinner based on the use you require it for.

• The type of paint being used - Some thinners only work with certain types of paints and varnishes. For example, mineral spirits only really work on oil-based paints (although they do this remarkably well) so if versatility is what you need then look for another more suitable option. Picking the thinner that works best with your paint choices will yield the best results.

Paint thinners jargon buster

Here at Cromwell, we want to make the process of purchasing from us as simple and easy as possible. To ensure that you select the right product for your desired application, we've outlined some key terms.

What are paint additives and are they the same as paint thinners?

The term paint additives refers to anything that can be added to paint to change or alter its properties. paint thinners fall into this category, as well as other products such as adhesion promoters, rust preventatives and water repellent additives.


Are paint thinners flammable?

In short yes. Many paint thinners are solvent based and as some are made from petroleum compounds, they can be highly flammable (as well as their fumes). For safety ensure proper storage away from heat sources of naked flames and you should avoid any form of naked flame when using paint thinners.

How do I store paint thinners?

Due to the toxic and flammable nature of paint thinners, it is vital that they are stored correctly. This includes making sure the storage environment is well ventilated, free from potential sources of ignition and making sure that they are kept out of reach of children or pets. Ensuring that the container (if decanted into another vessel for reuse) is clearly labelled with warnings.

Dispose of paint thinner at a proper hazardous waste facility. Pouring it down the drain can be incredibly toxic to the environment.