Halfway Between Oil and Acrylic: Alkyd Paint in the Spotlight

Alkyd paint has a long history behind it. If you are considering redecorating your interior or repainting your garden shed, you may appreciate the qualities of this paint. But beware, like all paints, it is not perfect.

What Is Alkyd Paint?

Composition and Characteristics: What Makes Alkyd Paint Unique?

Its versatility. Alkyd paint is a clever blend of chemical compounds that create a product with unique properties.

But before discussing that, let’s first explain that this type of paint is made from an alkyd resin, which results from a condensation reaction between polybasic acids and polyfunctional alcohols.

We mention this because the name “alkyd” comes from these compounds, as it is a contraction of the words “alcohol” and “organic acids.”

Once applied to a surface, this paint will dry to form a protective film that is insoluble and, importantly, cross-linked. We will revisit this term in the next section.

Before that, let’s continue discussing its versatility. Alkyd paint was specifically designed to be versatile. Its formulation is highly adaptable.

Thus, one alkyd paint may not contain the same compounds as another. For example, an alkyd paint intended for artists may contain a modified polyester resin made from:

• Pentaerythritol (polyfunctional alcohol)

• Orthophthalic acid (polybasic acid)

• Linseed oil (polybasic acid)

• Drying oil

• Benzoic acid (additive)

The purpose of this formula is to better resist oxidation caused by varying levels of ozone in a room (thanks especially to the additive).

Other alkyd paints aim to be completely VOC-free (volatile organic compounds) or to resist corrosion better. In the latter case, the nanoparticle scale is even considered.

For example, an alkyd paint called PANI, synthesized with polyaniline nanoparticles, resists corrosion better than an alkyd paint called POA, synthesized with poly-o-anisidine nanoparticles.

Consequently, alkyd paint is primarily a chemical solution whose compound modifications allow new characteristics to develop.

Of course, all this revolves around a common base of oils and fatty acids. Now you understand why this paint is described as halfway between oil-based and alkyd (or “glycero”) paint.

This oil base is also why alkyd paints are classified into three main categories:

• Short oil alkyd (35% to 45% oil)

• Medium oil alkyd (46% to 55% oil)

• Long oil alkyd (56% to 70% oil)

For example, our artist-grade alkyd paint is a long-oil paint composed of linseed oil. But it could just as well have been made with soybean oil, which, along with linseed oil, is the most commonly used substance in alkyd paint compositions (before or after water).

From all these manufacturing processes emerge general characteristics. Alkyd paint is:

• Low in toxicity

• VOC-free (for new formulations)

• As fluid as oil paint

• With a drying time between that of alkyd (glycero) and acrylic paint

• Suitable for multiple surfaces

• For interior and exterior use

• Washable with water (for brushes and rollers)

From Its Creation to Today: The Evolution of Alkyd Paint

Alkyd paint was born shortly after World War I, at a time when it represented the future compared with oil paints, which were then universally used alongside nitrocellulose paints. Its goals were threefold:

• To possess properties identical to oil paint

• To be less expensive

• To offer more versatile formulations

That is why alkyd paint is water-based, as it starts with the same components as the paint it intended to replace: water and oil.

At the time, the main problem with oil paint was its drying time, which could last hours and sometimes even days depending on humidity and temperature. With alkyd paint, drying takes 15 minutes to 1 hour.

This achievement is thanks to its cross-linked film. We mentioned this earlier, and it’s time to define it. To “cross-link” means that the film forms a network. In oil paint, the lack of cross-linking is what makes drying longer.

This is why artists such as Picasso, Pollock, Blake, and Lichtenstein quickly adopted this paint for their works.

As you may have guessed from our nanoparticle examples, alkyd paint has reached new heights today. This is notably the case with VOC-free paints, which require manufacturers and painters to master at least five key points:

• Composition

• Application technique

• Thickness

• Adhesion

• Substrate

To give you an idea of this evolution, manufacturers can now measure the capacitance and resistance of the protective film of their alkyd paints. That is, not only is the film’s permeability analyzed, but also the movement of ions through it. The 1920s are long gone.

Comparison With Other Types of Paint

The Paint Duel: When to Choose Alkyd or Latex?

Alkyd paint was developed to harden quickly. While it may lose to alkyd (glycero) paint, it outperforms latex paint. Indeed, latex paint requires a curing time of 3 to 4 weeks. For alkyd paint, the curing time is about 5 days (not to be confused with touch-dry time).

Ordinary alkyd paint also provides a glossy finish that latex paints cannot reproduce.

Only disadvantages of alkyd paint:

• It splatters during application

• It can crack over time

• It yellows in the long term

Durability is therefore not guaranteed. If you want a low-odor paint that lasts, latex is preferable to alkyd. However, alkyd paint adheres better to difficult surfaces.

Oil Paint and Alkyd Paint: Similarities and Differences

Oil paint is essentially a mixture of pigments and linseed or soybean oil. Alkyd paint is also a mix of pigments and oil, but includes alkyd resin. If you haven’t read the first part of this article about polybasic acids and polyfunctional alcohols, we recommend doing so now.

This alkyd resin gives the paint a glossier finish and, importantly, a much shorter drying time. It is also slightly less viscous than oil paint, while offering similar spreadability.

Why not use both? Repainting a wall already coated with alkyd paint using oil paint can produce a particularly fine, high-quality finish.

Water-Based Paints: Vinyl, Alkyd, or Acrylic

What matters in a paint’s name is its binder. Acrylic, vinyl, and alkyd paints are water-based (solvent) with an acrylic, vinyl, or alkyd binder. Therefore, when they dry, it is primarily the water (solvent) that evaporates.

The binder, which holds the paint components together on a surface, is pigmented for colour. As mentioned in our vinyl paint article, pigment also plays a role in the paint’s longevity.

Here is a comparative table of these three types of paints:

Advantages and Applications of Alkyd Paint

Weather Resistance and Outdoor Use

Although alkyd paint is perfectly usable outdoors, it ages less well than latex paint. A study on painted wood showed that after 11 years of exposure, latex paints, particularly those with linseed oil, flaked less than any alkyd paint.

Since critiques of latex paint often focus on its VOC emissions, its outdoor use avoids this issue. Therefore, we recommend choosing latex for outdoor applications.

However, aside from flaking, colour degradation, mould growth, and dust accumulation will be similar. If you can sand the wood, alkyd paint will do; otherwise, latex paint is better.

Limited Yellowing of White Colours

Oil-based paints yellow over time. It’s a fact, and no solution has yet been found.

Alkyd paint specialists know that yellowing comes from film formation, which relies on oxidation. Unsaturated structures in the paint produce this yellowing. Due to a high molar extinction coefficient, it is difficult to isolate these structures and replace them to prevent colour degradation.

Yellowing is also influenced by:

• Humidity

• Temperature

• Light

• Chemical exposure

• Pigments

• Oil

• Etc.

All these variables make formulating a solution extremely complex. If an oil-based paint claims not to yellow, consider it mostly marketing.

Ease of Cleaning With a Solvent

To clean alkyd paint, you can use:

• Clear water

• Soapy water

• Washing soda

• Baking soda

It is not only washable but also scrubbable.

Application on Different Surfaces, From Wood to Concrete

Alkyd paint can be applied to almost any surface. Always read the paint label to see which surfaces it suits.

Some alkyd paints cover both concrete and wood, while others cover gypsum panels, fibreboard, wood, or plaster.

Techniques and Tips for Applying Alkyd Paint

Choosing Between Matte or Satin Finish

The difference between matte-finish paint and satin-finish paint lies in its composition, making one more durable than the other. In this case, satin paint lasts longer than matte paint.

However, it also highlights wall imperfections more, as it reflects light. Conversely, a matte finish absorbs light.

Therefore, choose matte paint if your walls have imperfections, and satin paint for a smooth, flawless finish.

How to Dilute Alkyd Paint

Use a synthetic thinner. The amount to add can vary. In general, it may range from 5% to 20% of the volume of paint you’re using.

However, be careful—this rule doesn’t apply to all synthetic thinners. Some manufacturers may recommend specific ratios. For example:

• Maximum 5% for brush application

• Maximum 10% for spray application

Always follow the product’s instructions.

Which Roller or Brush to Use for Alkyd Paint?

It all depends on the surface you need to paint. If you’re painting wooden mouldings, using a silk brush is perfectly suited for a flawless result. On the other hand, if you need to cover large surfaces, you’re not going to tackle the job with a brush.

In that case, you can opt for a roller—but not just any type.

Painting With a Roller: Is It Possible With Alkyd?

Yes, but choose the right roller:

• Nylon and polyester

• Microfibre

• Fibre blends

• Natural fibres

For alkyd paint, only natural fibres work—often angora or lamb wool, suitable for all surfaces.

Safe Use of Alkyd Paint: Precautions

All paints come with a safety data sheet. Before using them, make sure you’ve read it. For alkyde paint, it’s common to find warnings such as:

• Skin irritation

• Allergies

• Possible carcinogen

• May harm fertility or the fetus

• Serious organ effects with prolonged exposure

• Potentially fatal if ingested or inhaled

• Flammable

• May spontaneously combust

Precautions include:

• Wearing masks, goggles, and gloves

• Washing exposed skin

• Leaving contaminated clothes on site

• Avoiding smoking, eating, drinking

• Ventilating or working outdoors

• Keeping away from heat

• Etc.

If you’re not comfortable with painting work, don’t hesitate to call in a professional.

Alkyd Paint on Wood Surfaces

Which Undercoat to Use for Alkyd Paint?

In this area, it’s important to distinguish between an undercoat and a primer. If your surface is new, apply a primer to allow the paint to:

• Improve adhesion

• Block stains (tannin, smoke, rust, water)

• Seal residual adhesive after wallpaper removal

For previously painted surfaces, an undercoat is sufficient.

Steps to Apply Alkyd Paint on Wood

1. Remove flaking paint

2. Sand with the grain

3. Repair imperfections

4. Wipe dust with a damp lint-free cloth

5. Apply primer

6. Paint the surface

How to Clean Alkyd Paint to Preserve Its Shine

Alkyd paint inherently suffers from:

• Yellowing over time

• Additive migration to the film surface

• Film wrinkling

• Crumbliness

In other words, to preserve your paint, and although it is washable and scrubbable, it’s best not to clean it excessively. Remember what we mentioned earlier about yellowing and its multiple causes.

However, if you need to remove a stain from a wall coated with alkyde paint, follow these steps:

1. Fill a bucket with 1 litre of warm water

2. Add a glass of washing soda

3. Add soap

4. Sponge wall from bottom to top

5. Rinse with clear water

6. Wipe with a clean cloth

Alkyd Paint and the Environment: What to Know

The overall environmental impact of alkyd paint is hard to assess. Alkyd resin production consumes significant energy, but few studies exist on local pollution near production plants.

A study led by Alexandria University (Egypt), published in 2018 as part of the 4th International Biotechnology Conference, makes it possible to quantify its impact in four main categories:

• Natural resources for production: 45.8%

• Ecosystem impact: 31.8%

• Human health consequences: 22.5%

• Climate change: 3.5%

The main raw materials behind these figures are alkyde resin and titanium dioxide, both of which are used in alkyde paint.

From these come the amount of fossil energy needed to heat a boiler from 190°C to 270°C in order to condense the polybasic acids and polyfunctional alcohols mentioned at the beginning of this article.

Consequently, with or without VOCs, the life cycle of alkyde paint is not neutral. However, it is far from being an exception in the paint industry. If you’re looking for an eco-friendly paint, simply keep in mind that some are less harmful than others.

Thus, unlike some acrylic paints, alkyde paint typically contains no heavy metals.

Alkyd Paint: A Contemporary Solution

Alkyd paint is a fascinating medium, positioned halfway between oil and acrylic. Its versatility, durability, and fast drying time make it an appealing choice for consumers seeking new possibilities. The combined qualities offer a unique experience, expanding creative horizons while preserving cherished traits of traditional media. This successful fusion positions alkyd paint as an exciting alternative, bringing vibrant new light to contemporary painting.