Water-Based Or Solvent/Oil-Based Paint – Which Is Best?

Below we provide some basic, common differences of solvent/oil based paint vs water based paint.

We must stress these are generalisations and of course there will always be exceptions to the rule. The aim of this is to provide a top level overview as an introduction to some of the main differences normally found between these two types of paint. Finally, there is of course many other types of paint available but this one is specifically focussing on products than usually fall within the generic description of water or solvent based.

The primary difference in solvent/oil based paint vs water based paint lies in the type of solvent used. Water-based paints use water as their solvent, which makes them (in general) easier to apply, clean up, and more environmentally friendly due to lower levels of volatile organic compounds (VOCs). They dry faster, emit less odour, and are safer for indoor use, particularly in spaces with limited ventilation. Modern water-based paints have improved significantly in terms of durability and finish, making them suitable for a wide range of applications.

In contrast, solvent-based paints use organic solvents like mineral spirits or turpentine, which (in general) result in a stronger odour and higher VOC emissions, and can take longer to dry than water-based paints.

 

When Should You Use Solvent-Based Paints

Solvent-based paints should be used in situations where their specific properties and advantages are most beneficial, such as low-temperature applications or where technology or chemistry is not able to provide a suitable water based alternative. They include winter work or projects in cold environments – walk-in fridges and freezers, for example.

It is recommended to use the solvent-based version of paints, such as Zinsser Allcoat Exterior Solvent-Based, when temperatures drop to below 10°C. Since water-based paints use water as their solvent base, they will be affected more by temperatures that are close to freezing, such as running and taking longer to dry.

Why Should You Avoid Solvent Based Paint?

Reasons to avoid using solvent-based paint may be due to its higher levels of volatile organic compounds (VOCs), which pose health risks such as headaches, dizziness, and long-term respiratory issues if inhaled. It also emits a strong odour. This may make the use of solvent-based paints unsuitable for interior projects and in enclosed spaces. Solvent-based paint requires the use of hazardous chemicals for clean-up and have a longer drying time. This can make them less convenient.

 

What Is Water Based Paint and Solvent Based Paint?

Water-based paint uses water as the primary solvent to dissolve the binders and pigments. It typically contains acrylic, vinyl, or latex resins as binders, along with various additives to improve performance. This type of paint is easy to apply, dries quickly, and typically can be cleaned up with soap and water. Water-based paints usually have low odour and emit fewer volatile organic compounds (VOCs). This makes them a more environmentally-friendly choice, and possibly more suitable for indoor use.

Solvent-based paint, also known as oil-based paint, utilises organic solvents. These can be mineral spirits or turpentine, to dissolve its binders and pigments, often alkyd, polyurethane, or epoxy resins. Solvent-based paints may require more careful application and clean-up with chemical solvents. They can dry more slowly than their water-based counterparts. This can be advantageous for achieving a smooth, glossy finish where desired. However, they can also have a strong odour and higher VOC emissions, posing greater health and environmental risks, especially if applying indoors.

 

Are Solvent-Based Paints Better Than Water-Based Paints?

Advances in water-based paint technology have improved their performance. They are a viable option for many projects that traditionally used solvent-based paints. This includes for use on wood and metal, where a lot of water-based paints don’t require a primer, just suitable and proper surface preparation. uPVC paints are also increasingly water-based, with long guarantees on their adhesion and performance such as colour fastness.

When water-based paints fail, it’s often due to using an inferior product rather than a specialised water-based paint. The saying “Do it cheap, do it twice” holds true when consumer-grade products are expected to deliver a professional finish or are used in commercial or industrial settings.

While the phrase “Does what it says on the tin” is commonly used to describe paint performance, the details in the product’s data sheet are far more crucial. Ensure proper surface preparation with suitable cleaners and degreasers. Adhere to manufacturer guidelines, and use abrasives and primers when necessary. This will help both water-based and solvent-based paints adhere properly and perform as expected.

How Can You Tell If Paint Is Water Or Solvent Based?

By considering paint characteristics and conducting tests, you can accurately determine whether a paint is water-based or solvent-based.

Label and Manufacturer Information

• Label Info: Is solvent based the same as oil based? The label on the paint tin usually provides some information about the ‘type’ of paint. Look for keywords such as “latex,” “acrylic,” or “water-based” for water-based paints, and “alkyd,” “oil-based,” or “solvent-based” for solvent-based paints. The label will also include recommended uses and clean-up instructions, which can further indicate the type of paint.
• Data Sheets: Available to download on each product page or from the manufacturer, with a separate safety data sheet listing chemicals and components.

Appearance and Consistency

• Water-Based Paints: These tend to have a thinner consistency, similar to milk or cream. They are easier to stir and apply, spreading smoothly over surfaces without much resistance.
• Solvent-Based Paints: These are generally thicker and more viscous, similar to the texture of honey or syrup. They may require more effort to stir and apply, often producing a heavier, more substantial coat.

Clean-up Method

• Water-Based Paints: Clean-up instructions will usually suggest using soap and water. This is because water-based paints can be easily removed from brushes, rollers, and other tools with water, making post-painting clean up straightforward.
• Solvent-Based Paints: The label will recommend using mineral spirits, turpentine, or paint thinner for clean-up. This indicates the presence of organic solvents that dissolve the paint, requiring these specific chemicals for effective clean-up.

This isn’t always the case, however, with hybrid products and 100% solid coatings. These may appear to be water-based but still require a solvent-based cleaner or thinner for application or cleaning. If in doubt, always ask an expert from the Rawlins Paints technical team.

Odour

Do not, ever, attempt to sniff or smell paint. Water based paints still contain some chemicals that can be harmful when inhaled and cause respiratory irritation, headaches, dizziness, and nausea.

Solvent-based paints contain higher levels of VOCs, which release strong fumes that are more harmful. Inhaling solvent-based paint fumes can lead to more severe health issues. These include respiratory problems, headaches, dizziness, nausea, and long-term effects like liver and kidney damage, and central nervous system issues.

If you or someone else has inhaled harmful levels of paint fumes, immediately call the emergency services for help on 999. Be sure to have the paint container to hand to provide accurate information. All manufacturer safety data sheets contain an emergency contact number should it be required.

It is crucial to use proper ventilation and protective equipment (masks, respirators) when working with any type of paint, varnish, oil, stain, sealer, etc.

Drying Time and Finish

Drying Time:

• Water-Based Paints: Often dry to the touch quickly, often allowing for reapplication within the same day. The quick drying time is due to the rapid evaporation of water.
• Solvent-Based Paints: These can take longer to dry, if not twice or three-times as long as water-based paints. This extended drying time can be beneficial for achieving a smoother finish, as the paint has more time to level out.

Performance and Longevity:

• Water-Based Paints: Advances in technology have significantly improved the durability and performance of water-based paints, making them suitable for a wide range of applications. They are less prone to yellowing over time compared to solvent-based paints.
• Solvent-Based Paints: These are generally more durable and resistant to wear and tear, making them ideal for high-traffic areas and surfaces exposed to harsh conditions. They provide a longer-lasting finish but may yellow over time, especially in areas not exposed to sunlight.

Can You Mix Water Based And Solvent Based Paint?

No. Mixing water-based and solvent-based paints is not recommended due to their fundamentally different chemical compositions. Water-based paints use water as a solvent, while solvent-based paints use organic solvents like mineral spirits. These solvents do not mix well, leading to separation and an unstable mixture, similar to oil and water.

Attempting to mix these paints can result in significant application problems. The mixture may not spread evenly, adhere properly, or dry consistently. This leads to a poor-quality finish that can peel or crack over time. This incompatibility negates the beneficial properties of each type of paint, such as the quick drying time and low odour of water-based paints, and the durability and smooth finish of solvent-based paints.

Additionally, mixing these paints can pose safety and health risks. Solvent-based paints have higher levels of VOCs, complicating ventilation and clean-up processes and increasing exposure to harmful fumes. Following manufacturer guidelines and using each type of paint as intended ensures the best performance and safety for your painting projects.

 

Is Solvent-Based Paint Oil-Based

Yes, solvent-based paint is often referred to as oil-based paint. Oil-based paint is another term for solvent-based paint, indicating the use of oil (such as alkyd or linseed oil) as the binder.

 

What Is Solvent-Based Paint Used For

 

Solvent-based paint, often known as oil-based paint, is used for applications that require a durable and resilient finish. It is ideal for high-traffic areas such as doors, trim, and floors due to its resistance to wear and tear. This type of paint is also preferred for exterior surfaces like siding, fences, and outdoor furniture because of its ability to withstand harsh weather conditions. Additionally, solvent-based paint is commonly used in industrial and commercial settings, as well as for marine and automotive applications. Its superior adhesion and glossy finish are crucial for protecting surfaces and providing a high-quality appearance.

Further Information

Questions about the use or suitability of solvent-based paints? Leave a comment below for Rawlins Paints’ technical team to review. Alternatively, you can talk to them directly.