Cornstarch to Flatten Paint – Will It Work? And When May You Need It?

Are you looking for a way to flatten paint without any harsh chemicals? Cornstarch might be the answer for you! This substance can replace traditional paint thinners and can be used on many surfaces as a flattening paste. As an artist, you’ll sometimes want to reduce the sheen of paint, probably because it’s too glossy or because you do not like the final result. This is where you will use cornstarch.

However, it is important to note that cornstarch should only be used as a last resort. If other methods of flattening the paint have failed, cornstarch may be your best option. Continue reading for more information on painting with cornstarch, including helpful tips on safe handling and shopping for and using the product.

What is Cornstarch?

Cornstarch, or cornflour, is made from the endosperm of corn. It’s a carbohydrate that’s around 9 percent water and about 2 percent alcohol by weight. It looks like tiny pieces of chalk and is usually sold in the grocery aisle but can be found online, often called corn meal. Cornstarch is a common household ingredient used to flatten paint and other materials. It absorbs water droplets and creates a film that holds the material together.

Will cornstarch work as a flattening paste?

Yes, cornstarch can serve as a flattening paste. It is a highly absorbent material used in various industries to absorb moisture. It can be used as a dry ingredient in foods to add moisture or as a thickening agent in many other applications. It works so well for painting because it works very well in all of these applications: it absorbs liquids easily. However, this same property makes it difficult to work with because it is also very sticky.

When adding cornstarch to a liquid, you must work quickly and carefully to prevent the substance from becoming too thick. If it becomes too thick, it will be difficult to use, and the quality of your finished work could suffer.

While adding cornstarch directly to paint can cause problems if not carefully controlled, mixing the cornstarch into the water before applying it is generally easier. Mixing the two makes using it much less complicated by creating a thinner mix that is easier to handle.

How Can I Use Cornstarch to Flatten Paint?

There are many different methods by which you can use cornstarch with painting.

  • Flattening Surface

While painting without a finish can be dangerous, you can use small amounts of cornstarch mixed with paint to flatten the surface when you are finished. This mixture will work best if applied with a brush or sprayer and then allowed to dry. The final result may not always be completely flat, but it does work well for many pieces.

  • Thinning Paints

Adding cornstarch to paint can greatly reduce its overall thickness and allow thinner layers to be applied. While this can be a helpful technique, it is important to note that it will not work on every surface. Always test the mixture on an inconspicuous area before applying the paint over a larger surface.

When using cornstarch with water, you should add approximately 1/3 cup of cornstarch for every 32 fluid ounces of water to create an optimal mixture. Simply pour the solution over your wet surface or apply it with a brush. You should allow the solution to dry before painting additional layers onto your work.

  • Staining Paint

You can also combine cornstarch with paint to achieve certain color effects. For example, you could use cornstarch instead of the regular wash to create a more intense look on certain colors or change certain colors altogether. However, it is important to note that cornstarch will not work with every color combination. Always test the mixture on an inconspicuous area before applying the paint over a larger surface.

Mixing Cornstarch Into Your Paint Formula

If you feel that the odor of cornstarch may ruin your painting experience, there are some solutions you can try to reduce or avoid this issue. One solution is to mix the cornstarch into your paint instead of using it as a thinning agent.

This option works well for most surfaces, but you must be careful to keep in mind that every mixture will behave differently. You should also use thick paint for this application, as the mixture will become too thin to apply if you use thinner layers.

How Much Cornstarch Should You Use?

When properly used, cornstarch is a very helpful substance. However, if you do not follow certain steps while using it, it can become unusable and ruin your piece of work. While this may be something you are willing to sacrifice if needed to secure the effects you want, there are a few potential problems that may arise with the amount of required cornstarch in your mixture.

Too much cornstarch can make your final piece look dull and blotchy instead of smooth and consistent. It can make your paint too porous, allowing the mixture to crack and separate before drying. Finally, if you use too much cornstarch, it will not be able to absorb all of the water from your paint. If this occurs, you may use a thinner mixture to get the best results and prevent these issues from arising. Check out how to produce a “flattening paste” with cornstarch.

How to use cornstarch to make a paint flattening paste

If you’re looking to make a paint flattening paste, you’ll need a few things:

  • Cornstarch
  • Water
  • Your paint palette or other crafting supplies

Step by Step Guide on how to apply cornstarch to flatten paint

Cornstarch is a common addition to paint for flattening lines and creating a more even surface. Follow these simple steps to apply cornstarch to your painting:

  • Add three tablespoons of cornstarch to a measuring cup and mix with four ounces of water until thick paste forms.
  • Pour the cornstarch mixture into a bowl or glass jar.
  • Use your fingers or an electric mixer to combine the water and cornstarch until smooth.
  • Pour the cornstarch mixture into a clean, dry paint can.
  • Add your paint to the cornstarch mixture and stir until the paint is completely mixed.
  • To apply your cornstarch and paint mixture, use a brush.
  • Try it on a small portion to ensure it gives you the desired finish.

How Can I Control Cornstarch?

Controlling cornstarch properly is important for safely applying it to your surface. If you are not careful, you may have an unsightly mess on your hands and your project ruined before it can dry. While you cannot completely control what cornstarch you are using, there are certain steps that you can take to help reduce the possibility of an ugly mess.

The first thing you should do is ensure the cornstarch is thoroughly mixed into the water before adding it to your paint. This will help avoid large clumps of thick material in your mixture and may help improve the results of your work. You should also test on a smaller area before applying your rich mixture to determine if it will work well for your project or not. If you have some water left over after thinning with cornstarch, wait for it to dry before continuing with painting.

When should you use cornstarch as a flattening paste?

Using cornstarch is a good solution for problems you might have with paint. The main application where you would use cornstarch is when your painting is not flat, and you need to flatten it out so that top coating can be applied.

If you use cornstarch, remember that it takes time to dry and should be done in a well-ventilated area to avoid breathing in the cornstarch particles. You also want to ensure the room temperature is warm enough for the paste to dry properly. Another thing, don’t forget to clean all work surfaces after using cornstarch to flatten paint because it leaves a residue on all surfaces.

Speed of Cornstarch to Flatten Paint

While cornstarch can be used as a dryer, it has a quicker drying time than the usual dryers and paints. This can make it almost useless when trying to speed up how fast the paint or oil dries. You might be able to use cornstalks for this purpose, but not too many other dryers, as these will cause additional damage. You could also use alcohol or turpentine for that purpose, but these would also dissolve your oil-based paints.


Our final word on the subject is that cornstarch is one of the options used for flattening your paint. You could use it to reduce the sheen on your paint. You can use cornstarch to convert a glossy finish to a matte finish.

If you want to use it, take precautions when working with it and test out the mixture before applying it all over your finished painting. This may be a great solution if you are looking for an eco-friendly alternative to all those harsh chemicals.