How to Thicken Acrylic Paint

Acrylic paint is a versatile and popular medium. It’s also very easy to use, which means that even beginners can work with it without much trouble. But sometimes you may want to thicken acrylic paint in order to create a specific texture or add more body, especially when working on larger surfaces. This article discusses the different ways of thickening acrylic paint and offers tips for how to do so effectively!

Why Is Your Paint Texture Important?

There are several reasons why you may want to thicken your acrylic paint. As mentioned above, one of the biggest advantages is that it gives artists more flexibility in terms of their application techniques and end results.

However, thickness also affects other factors such as drying time and how much light exposure a painting can endure without cracking or fading away.

If you’re working on a large surface with thinned-down paint then this will need longer to dry than an opaque thick layer that has been applied directly to the canvas (or board).

The amount of exposure your artwork receives from sunlight will affect how quickly it dries too – when acrylic paints dry they become less permeable so applying thicker layers reduces the risk of cracks forming where moisture seeps through over weeks or even months.

Why Is Your Acrylic Paint Watery or Thin?

There are several reasons why you may find your acrylic paint has become too thin for your liking. It could be that the pigment levels have dropped, or maybe there’s not enough binder in it. The biggest problem is often down to storage because sometimes manufacturers open up a new batch of paints and don’t close them properly afterward.

Another reason is if you add a little bit of solvent such as alcohol to help speed up the process and make it easier for the paintbrush to move over the surface when applied.

The downside with this approach is that once dry, any excess solvents in your paint will evaporate leaving air bubbles within its layers which can cause cracking in your artwork later down the line – especially when exposed to sunlight.

If using a brush then this isn’t usually an issue because brushes tend not to leave streaks behind whereas rollers and sponges can.

Other things like temperature fluctuations during transport will affect consistency so street artists might want their paint particularly thick so it stands up to being handled.

How to Thicken up Acrylic Paint

There are several different ways that you can thicken your acrylic paint. You’ll get a better result if you experiment with each one to see which works best for the end results you’re looking for!

Acrylic Painting Mediums

Gel Mediums

Using gel medium is perhaps the most popular approach because it’s so effective and easy to use. The downside is that once dry, gel mediums tend not to produce a very matte finish on paintings which some artists don’t like… although others swear by their unique textured look.

Gel paints do have some advantages though – they stick really well when dry and add more body too, especially useful when painting large surfaces without having to thin down your colors again afterward (which produces its own set of problems).

The main downside is that they’re not very transparent so adding gel medium to your paint will darken it. If this is an issue then you can use acrylic gloss or matte mediums instead which are more effective at thickening the consistency of the color without altering its hue too much.

Gel mediums also tend to be quite pricey – especially when buying several different tube sets, tubes, and jars (not to mention brushes).

Acrylic Mediums

You may be surprised, but many artists actually prefer using acrylic medium instead of gel because it’s cheaper and gives them more control over what goes into each tube of paint – especially when making custom colors for specific projects! What’s even better is that there are so many different brands out there that choosing one isn’t hard either.

The problem with this approach though is that most acrylic mediums are not very effective at thickening paint unless added in large amounts.

You’ll find that many artists work their way through dozens of tubes just trying to achieve the right consistency for a specific project – but it’s worth the effort if you want perfectly controllable paints without having to spend too much money on them!

If using acrylic medium then you will need to add lots more pigment so your colors won’t be transparent after mixing with gel or gloss, which can reduce vibrancy and saturation levels along with opacity depending on how much is used (although the matte medium isn’t quite as bad). It shouldn’t ruin anything though because there are plenty of other ways around this problem when applying paint onto surfaces like canvas.

Molding/Modeling Paste

If you’re looking for a thickener that can be applied just to specific areas then this is often the best option, especially if your project needs it in both wet and dry stages. Mixtures of pastes are also great at producing several different textures too so they’ll work well on large or small surfaces alike!

Fluid Mediums

A lot of artists like using fluid medium instead because it’s more transparent than acrylic gels which opens up new possibilities when mixing with colors (although some types do come with their own problems). The fluid medium isn’t very effective though unless added in vast quantities.

Paste Mediums

Pastes do a similar job to modeling paste but are better at thickening acrylic colors without changing their transparency levels too much since most of them have no added pigment (unlike gels or matte medium which does).

You may need to experiment with different brands though because some tend not to be very effective unless used in high concentrations – so always ask if you’re unsure about what will work best for you!

Texture Gel

Texture gels are usually more effective at thickening paint than other types of mediums due to the fact that they’re designed specifically for this purpose. These tend to be quite pricey though especially if you use them on a regular basis – so it’s probably best just buy one jar or tube and use it sparingly when needed!

How to Make Acrylic Paint Thicker – DIY Solutions

There are tons of different ways to thicken acrylic paint ranging from using household objects right up to mixing inexpensive mediums – but not all methods will work for everyone. We are going to briefly mention the most common ones below, along with reasons why they might be less effective than others.

Thicken Paint with Cornstarch

Making a cornstarch thickener for acrylic paint is super easy and it’s another great, cheap solution to your problems.

In fact, this household ingredient has many great uses in the art world including using it as a binder, fixative, or sizing agent. It can even be mixed with pigments to make paints more opaque but these colors tend not to last very long though since starch baths are acidic!

There aren’t too many cons associated with mixing up a batch of homemade cornstarch mixture besides the need for constant stirring (and having extra brushes on hand) – which makes painting quite difficult sometimes. You also need an awful lot of cornstarch before you get any results compared with other methods so remember that if you are looking for an easy alternative to commercial thickeners!

There are also many ways how to make acrylic paint thicker without cornstarch.

Using Flour to Thicken Acrylics

The reason white flour was used so often is that it’s cheap, readily available, and has been used for many years. It can work well when mixed with water or acrylic paint but there are some problems that you will need to consider first – which include the fact that this solution makes colors matte (which isn’t great if you want a glossy finish) along with an increase in surface tension, causing your paints to lose their flow easily.

The flour will only work on acrylics if the colors are very diluted. The reason for this is because flour can’t absorb any moisture from an already saturated mixture of color and medium – which means you’ll need to add quite a bit too!

Flour is one of the least effective methods for thickening acrylic paint – especially when used with gloss medium.

Using Glue and Flour to Thicken Acrylics

Mixing glue with flour or water can sometimes produce a result that’s halfway between what you get from mixing each of these ingredients separately. This method is usually more successful at thickening colors enough for a glossy finish without completely flattening them – but it’s not as effective at making the paint more opaque.

Mixing Joint Compound with Acrylic Paint

Joint compound is another common household item that can be used to thicken up paint since it has pigments in (which some people like), along with the fact that this particular type of paste has amazing texture-building properties!

A joint compound isn’t very effective for thickening acrylic paint either but it is better than adding flour. It has a similar problem to matte medium in that the mixture dries out quickly and becomes harder to work with long before you’ve even finished your painting project!

It will also add texture which might not be desirable when coating surfaces such as canvas – so always try using this solution on small areas first if possible just to see how well it works!

Using Gelatin to Thicken Acrylics

Gelatin is yet another household ingredient that can be used in art. It is an interesting thickener because it absorbs liquid in much the same way as plaster of Paris so the more you add, the thicker your paint will become – although there are a few caveats associated with this method of thickening acrylic paints.

Not everyone likes using gelatin because it adds weight to finished paintings, which means they might not hang straight. This type of mixture also tends to crack easily when dry and while some artists love how glossy or smooth their work becomes once dried, others find that the surface has ridges instead.

The good news though is that if these issues don’t bother you too much then gel medium could well be a good solution to your problems.

Thicken Paint with Powdered Milk and Flour

If you’re willing to put in the time and effort, then making a paste from powdered milk and flour is yet another option when it comes to thickening acrylic paints.

You need equal amounts of each ingredient so don’t worry about getting measurements wrong! Although this mixture doesn’t thicken up the paint very much at all, its main benefits are that it can be used with gloss mediums (which most other solutions cannot) – plus many artists like how glossy their finished work becomes after drying!

This method also imparts no texture which means there’s less risk involved for painters who want an even finish on canvases etc…

The cons associated with using this mixture are that you need to experiment with the technique a little before seeing any results, plus it’s not very effective at pushing paint into corners or onto surfaces.

Using Sand to Thicken Acrylics

You’re probably better off avoiding this method too because it can produce a gritty texture on your paintings over time instead of making things thicker (although it might be okay if you want an aged or distressed look).

Using Methylcellulose

Methylcellulose is one of the most powerful types of medium used specifically for thinning and adding texture to acrylic paint! It has unique properties that allow it to do both jobs simultaneously without any adverse side effects aside from an increase in drying time.

It’s more expensive than most other mediums on this list but it also works much better too! This means you can use less of it at a time so your budget won’t be blown quite as quickly.

When using methylcellulose in order to thicken up acrylic paint – mix it first with either water before adding any color. You’ll need to experiment until you get good results each time because every brand has different measurements and reaction times.

Mixing up Thickened Acrylic Paint for Texture and Effects

If there are certain areas within your project where you want to achieve a textured appearance then you might want to consider mixing up thickened acrylic paint with things like sand, salt, or glitter.

When mixed together in small quantities – these ingredients can create some very interesting effects that are perfect for creating textures on surfaces such as canvas! Just be careful not to use too much at once because this will lead to excess residue accumulating which isn’t easy (or fun) clean off!

Tips for Using Acrylic Paint Thickeners

Don’t use gel or paste thickener with gloss varnish, but water-based ones are fine.
If you’re adding texture to your paintings (such as sand) don’t go overboard otherwise it’ll start looking messy.

Always remember that anything which interferes with the pigments and colors can reduce how long your art materials will last.
Only add a little bit of medium at once. You can always mix in more later but you’ll have problems if there is too much!
Add just one type of thickener to your paint, not several. This will minimize the risk associated with adverse reactions between different ingredients and produce better results overall!

Don’t use methylcellulose as a substitute for water or gloss mediums – it’s going to take far longer than normal to dry this way.

Adding a lot of medium means that an acrylic painting isn’t going to be very stable so don’t expect any layers under paintings made using these methods to last for years without starting/becoming damaged.

For more acrylic painting tips read our How to Blend Acrylic Paint beginner’s guide.

Final Words

Hopefully, you now have a better understanding of how to thicken acrylic paint and what’s the best way to go about doing this.

Acrylic paints can be difficult because they dry quickly (which is great for most projects!) but it also means that if there are any issues with your mixture then you’re going to notice them very soon.

It’s always important that you take extra care when adding mediums into the mix as these will change everything! If things aren’t working out then just remember that practice makes perfect so keep trying until you get it right – don’t give up at the first sign of trouble, instead of do whatever needs to be done in order to produce results that meet all required standards 🙂

Table of Contents

How to Thicken Acrylic Paint: Everything You Need to Know