How to Thicken Enamel Paint: A Complete Guide

Enamel paint is a great choice for projects that are subject to hard wear and need some durability. They give a nice, smooth look and a slight sheen that really perks up a project. However, if the paint is too thin for some reason, it can affect the application and the final project.

How to thicken enamel paint: A paste can be made using beeswax and turpentine or a thickening agent can often be purchased at hardware or home repair store. Another option is to open up the can and allow air to help thicken the paint.

Working with enamel paint can take special care.  Enamel often has longer drying times and requires extra effort and supplies for cleanup.  It can result in that harder, more durable, shiny surface that makes it all worth it.  But it is important to know how to work with it. This guide is here to help!

How to Thicken Enamel Paint

If you find your enamel paint is watery, too think or appears to have separated despite having been shaken and stirred, you may want to try to thicken it up.

Thickeners that work with latex paints won’t work with oil-based enamels. Depending on what kind of enamel paint you are using and for what application, you may be able to use one of the following:

·         Air it out. Open up the can and let some air in. Monitor and occasionally stir until you get the right consistency.

·         A thickening agent, available at your local hardware store. Speak with an expert to know what will work for what kind of paint you have.

·         A mixture of beeswax and turpentine works well to thicken some types of oil-based paints.

Generally, having your enamel thicken-up on you and require thinning is a more common issue with enamels. But, should you find that your enamel paint is too thin, check with your local paint or hardware store to see if there is an option that will work for the enamel you are using.

Never start mixing substances into paint without first knowing if what you are using is compatible with what is in your paint.

Enamel Paint Basics

Enamel paint is actually a category of paints that are oil-based products that typically have a significant amount of gloss.  Often the term is used to mean a “hard surface washable paint.”

Enamel paint should not be confused with painted enamel, which typically applies to vitreous enamel.  Vitreous enamel is a powder or paste that is painted on an object and must be fired at a high temperature.

The term enamel paint is generally applied to paints that are of higher quality, spray paints, or glossy finished floor coatings.  The name is really a mislabeling as commercially available enamel paints are considerably softer than vitreous enamel and are totally different in compositions.

What we’re getting at is this: no single, standard definition of enamel paint exists.  Not all enamel-like paints are labeled as such.

Here are some basics about enamels:

  • Enamel paint used to be nitro-cellulose-based paints.
    Nitro-cellulose paints were more commonly known as lacquers.  However, those paints have been replaced by newer synthetic coatings, such as alkyd resin, acrylic, and vinyl because of toxicity, safety, and discoloring over time.
  • Enamel paint can also be made by adding varnish to oil-based paint to increase the shine. Glass powder or metal flakes may be used for coloring instead of pigment.
  • It comes in a wide variety of colors and applications making it extremely versatile.
  • It creates a durable and lasting finish.

How to Work with Enamel

When using enamel paint, it is important to have the right paint and supplies, use the right brush strokes and process, and to complete the appropriate cleanup.  It can be tricky when using enamel for the first time.  Patience is important as more so than a flat or semi-gloss; enamel is unforgiving of errors.

Choosing the Supplies

Before getting started on any paint project, you have to assemble the right tools and supplies.

Your first step is to decide if enamel paint is right for the project.  Enamel paint is not appropriate for every job.  It is often best suited for outside items that receive exposure to moisture and extreme temperatures.  In the home, enamel paint works best for areas that receive heavy traffic and areas with high levels of wear and tear.  Enamel paint also works well for areas that will need frequent cleanings.

Choose the right paint.  Although enamels are usually oil-based, water-based enamels have been developed.  Water-based enamels dry faster, are easier to clean, and easier to use.  Oil-based enamel will last longer and has a slicker, more durable finish.  The choice is often one of preference.  Make sure you consider all options before choosing the right paint for the project.

Painting with enamel requires high-quality brushes.  A Chinese or ox-hair brush will help spread the thick oil-based paint.  Synthetic fibers work best for water-based enamels because they won’t soak up the water in the paint and become soggy.  Angle brushes can help get the smooth finish that enamel paints need if they are going to dry slick and glossy.  Dedicate brushes to either oil-based or water-based use.

Applying the Paint

Before you get to the fun part, the surface you’re painting needs to be prepared and thoroughly cleaned prior to applying the primer.  Then, the enamel paint needs to be completely stirred prior to application.  Enamel paints can be toxic, so wearing a mask, especially indoors, is important.

Start with a primer. Primers are products that prepare the surface.  This helps fill crevices, cover flaws, and give the paint a uniform area to adhere to.  Most primers are oil-based, which helps in sealing the wood.  A coat of primer is recommended before applying enamel paint, especially to indoor surfaces, furniture, and cabinets.  Check the label as some enamels have a primer already mixed into them.

Enamel paint’s smooth, glossy finish makes imperfections more visible.  So, it’s crucial to be careful in the application. Here are some steps for avoiding marks and brushstrokes.

  • A “tip-off” stroke helps make sure the paint is unmarred.
  • Using an angled brush wet with paint, make a second pass with only the tips running over the surface just painted.
  • Drag the brush the entire length of the painting surface (with the wood grain) in one fluid brush stroke.
  • Keep brush strokes as even as possible.

Enamel paint can also be applied by spray.  This helps make sure the paint goes on evenly.  It can also save time when there is a large area to cover.  Enamel paint may need to be thinned to help it go through the sprayer.  It may take some practice to not over apply and have runs with the paint.

Painting Tips

  • In general, a few thinner coats result in faster drying times and a better-quality finish. A single coat or couple of heavier coats doesn’t get the same effect or look.
  • Enamel paint will need two application coats. This will increase the protective coverage, durability, color integrity, and seamless.  Anything that is exposed to weather will definitely need two coats.
  • The paint will need to dry between the coats.

Drying Times

Oil-based enamel paint requires longer drying times than water-based paints.  It will need 8-24 hours to dry completely due to the thickness.  Temperature and humidity will impact drying time causing projects to take longer, especially when outside.  It is better to do outside painting projects when it is warmer and dry weather to ensure a better drying process.

Water-based paint will take about 1-2 hours or less to dry.  Some special formulas of enamel are quick-drying and will dry in as little as 15-20 minutes.  Make sure and do not disturb the wet paint to prevent smudging or other problems.  Water-based enamel will dry from the outside in, so care needs to be taken after it is dry to the touch to ensure that it is thoroughly dry prior to washing.

The enamel paint should feel dry to the touch.  If it is still tacky when touched, it needs to dry longer before the next coat or being put into use.

Cleaning Up

Typically, mineral spirits or paint thinner is used for oil-based paints, stains, and varnishes.  Alcohol is used for shellacs.  But, always check the paint can.

  • Pour enough solvent into a glass container to cover the brush bristles.
  • Dip and swirl the brush in the solvent, repeating the process until the bristles are clean.
  • Spin the brush by hand or with a spinner to remove the solvent.
  • When it is dry, replace into its plastic protect jacket to help maintain the proper shape.

Combing the bristles will help remove any dried paint and get the brush back into shape.  This will also help the bottom of the brush from filling up with hardened paint.  Brush combs are available at most hardware stores.  Once combed, the brush can be hung up to dry or set on a flat surface.

Categories of Enamel Paints

Enamel paints are multi-functional and have a wide variety of uses.  The glossier the paint, the harder and more durable it will be.  Enamel paints hold up well in places that will have to stand up to substantial wear.

Surfaces that may need frequent washing or have to endure high temperatures also do better with enamel paints.  Enamel paint provides surface moisture, chip, and corrosion resistance.

Some enamel has additives that help with rust and mildew prevention.  Enamel also adheres to a large number of surfaces making it versatile in what it can be applied to.

  • Floor enamel – May be used on either concrete or wood. Great for stairs, basements, porches or decks.
  • Fast Dry Enamel – Will dry in 10-15 after application. Often used for appliances, counter and other industrial finishes.
  • High-temperature enamel – Used for items that are in high situations, such as engines or BBQ’s.
  • Epoxy Enamel (Polyurethane) – Used for a protective coating purpose, especially in the chemical and petrochemical industries for anti-corrosion purposes. They are also often used as a floor enamel.
  • Nail Enamel – Used to color nails, it is often fast drying and comes in a variety of colors.
  • Model paints – There are many mainstream commercial paints for use on models. They come in a variety of colors and dry with a high gloss sheen.  Some brands focus on authentic accurate military colors for military models.
  • Wood Enamel – Used on wood that is going to be exposed to the elements. It helps the wood last longer by making it more resistant to wear, waterproofing, and rot-proofing.

Common Problems

Enamel paints are prone to certain problems, but many of them can be prevented with careful application.


  • Possible Causes
    • Paint is too low of quality
    • Paint is too thin.
    • Poor surface preparation.
    • No primer used
    • Excessive hardening of enamel/oil-based paint as the paint ages.
  • Possible Solutions
    • Remove loose and flaking paint, using a wire brush or a scraper
    • Sand the surface and feather the edges
    • Prime bare wood before re-painting.
    • Use top quality primer


  • Possible Causes
    • Area receives little to no direct sunlight and is often damp.
    • No primer used
    • Lower quality paint used.
  • Possible Solutions
    • Test with few drops of household bleach, if discoloring is bleached away, it is likely mildew.
    • Scrub with diluted bleach in water.
    • Re-paint if possible, enamel-based paints are not suited for this type of area.

Mud Cracking

  • Possible Causes
    • Paint is applied too thickly
    • Paint builds up in corners during application.
  • Possible Solutions
    • Remove paint by scraping and sanding.
    • Prime and repaint using acrylic instead of enamel paint.


  • Possible Causes
    • Applying any oil-based paint over a damp or wet surface
    • Moisture seeping in the wall from the backside.
  • Possible Solutions
    • Scrape and sand as long as the blisters do not reach the material below.
    • Re-paint after ensuring the surface is completely dry.
    • If blisters go to the underlying surface, find the source of moisture and address it before attempting to repaint.
    • Once the moisture is removed, scrape, sand, and repaint.


  • Possible Causes
    • Paint applied too thickly.
    • Painting when it is extremely hot or damp
    • High humidity before paint has finished curing
    • Not thoroughly cleaning the painting area.
  • Possible Solutions
    • Scrape and sand to removed wrinkled paint.
    • Use primer and allow to dry completely.
    • Repaint


  • Possible Causes
    • Using enamel paint over a more flexible coating, such as acrylic primer.
    • Applying the next coat before the previous coat is dry.
    • A natural aging of oil-based paint due to temperature fluctuations.
  • Possible Solutions
    • Remove old paint
    • Use a high-quality primer
    • Re-paint with acrylic paint.

Eco-Friendly Paints

Enamel paints used to be extremely toxic to both the people using it and the environment.  They can give off fumes that are very irritating, especially when used indoors.  Since they have oil and various

solvents, they can be flammable when still wet.  It is very important to take care of wet rags used to clean up spilled paint or used it in clean up.  This had led to calls for more environmentally friendly paint.

All paints potentially contain volatile organic compounds (VOC’s).  These are what make the fumes toxic.  Many paint companies have started making latex paint that is low to no VOC’s.  The problem with enamel is finding solvents that will create the same high gloss shine, which also hardens to create durability, without adding solvents with VOC’s.  This has been a struggle.

Water-based enamels have been one solution.  They are typically not as toxic as oil-based.  But, water-based enamel does have some issues.  It is prone to chipping, does not have the same silky, shiny finish, and it is not suitable for moist environments, especially if it may keep the enamel from drying fully.

Alkyd-based Enamels

Alkyd-based paint is a new enamel paint that uses the latest technology.  It combines the best of oil-based and acrylic enamels.  It has quicker drying times, gives a highly professional finish, and a better gloss.  Alkyds are polyester with the addition of fatty acids and other components.  The inclusion of fatty acid makes for a more flexible coating. They are considered oil-based but actually have no oil.

Alkyds are a resin that serves as a “binder.”  They give the paint the smooth, hard finish that people have come to expect of oil-based paints, but without the VOC’s or any smell.  The other factor is that alkyd-based enamel easily washes up with water.  It can be used for a wide range of applications and like oil-based enamel helps prevent mold, mildew, and fungus.  It comes in a full range of colors.

Washable Flat Enamel

One common misconception is water-based flat paints are a version of enamel paint.  The paint is typically marketed as having limited or no sheen, but still maintaining the durability and washability of regular enamel.

This is not technically correct information.  These paints are often softer than regular enamel paint.  It is important when buying a flat enamel to read the label for suggested uses.

Other options

There are some other paint manufacturers that are starting to offer more and more VOC free paints and enamels.  As different countries around the world continue to enact laws limiting VOCs in paint, the selection is likely to keep growing.  Currently, many of the paints offered are in only select colors and extremely expensive, but that is changing.

Vinyl and acrylic enamels are another way manufacturers are trying to make less toxic enamel paint.  Changing the colorants has also been used as a way to decrease VOCs.  Over time, these products have improved and are likely only to keep getting better until the difference between then and “old fashioned” oil-based enamel is not apparent at all.

Enamel paints are a popular choice for many home projects.  Using enamel can be very simple and easy if a few simple directions are followed.  It is important to use a high-quality brush, roller, or spray equipment.  The paint must be carefully applied using a tip-off method until a nice smooth finish results.

Enamel will take longer to dry, but the result is a hard, durable sheen that will outlast most other paints.

Many of the problems people have with enamel paint can be prevented by allowing complete drying between coats, having a prepared and primed surface, and not putting the paint on too runny or too thick.  Now that they come in eco-friendly versions, it is a great time to give them a try.

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