For traditional pottery made with pottery clay, the creations need to be fired in a kiln to cure and properly seal. Once the clay has been cured, it’s generally safe to use with water and food.
Air-dry clay doesn’t need a kiln to cure; it dries by allowing the moisture in the clay to evaporate naturally in the air. Unfortunately, this means that if the clay is reintroduced to moisture, it will become soft again. As such, air dry clay isn’t naturally waterproof.
So, how can you make air dry clay waterproof? While air dry clay can’t be completely waterproof, you can make it water-resistant by applying 1-3 coats of varnish, acrylic or water-based paint, Mod Podge, or liquid epoxy resin to the final product. However, these materials are not food-safe.
Each of these sealing methods has their own strengths and weaknesses and are best used for specific purposes. We’ll review each method in detail so you can determine which method is best for your pottery creation made with air-dry clay.
Why Air Dry Clay Isn’t Waterproof
Air-dry clay has a much softer feeling, like Play-Doh or Model Magic. It’s more moldable than pottery clay and is more flexible to work with.
As we mentioned above, air dry clay dries through evaporation. In 24 hours, it will be dry to the touch, and within 72 hours it will be completely dry throughout.
Because air dry clay dries by allowing the moisture in the clay to naturally evaporate in the air, the material in the clay is still susceptible to moisture. Once you reintroduce a liquid to dried air dry clay, it will become soft again through reabsorption of moisture.
Due to its delicate and absorbing nature, air dry clay can never truly be waterproof. However, there are seals and finishes you can apply to air-dry clay to give it a water-resistant quality. It won’t be able to hold water for a long period of time but will withstand a rainstorm or light washing.
It’s important to note that none of the methods for making air dry clay water-resistant are safe for food. Never use air dry clay pottery for food or drinks of any kind as you will run the risk of toxic materials leaking into the food or drink you consume.
Let’s review the different options for sealing your air dry clay to give you the right level of water resistance for your decorative pottery.
Types Of Sealants For Making Air Dry Clay Water-Resistant
Now that we’ve discussed a little bit about the natural state of air-dry clay and warned you against using it as a material to serve food with, let’s get into the methods for making air-dry clay water-resistant.
Although varnish is traditionally used to seal wood, it works great for air dry clay too.
You can choose to purchase spray-on or paint-on varnish; either one does a good job of sealing your air-dry clay, so pick the one you’d feel most comfortable applying.
For best results, we recommend using a clear polyurethane varnish to seal your air-dry clay. This will provide a layer of protection against water and dust without altering the look of your pottery.
You can find varnish in different levels of finish from matte to glossy, so read the label and choose the one that will give you the finish you’re looking for.
Varnish is a good option for pottery you plan to display inside or outside. It offers a layer of protection that will stand up to rain outside or any spilled liquids inside.
Apply your varnish according to the label directions. Make sure that as you paint or spray the varnish onto your pottery, you’re reaching all the crevices, divots, and corners that may exist in your piece.
Any holes or missed patches in the varnish seal will weaken the water resistance and make your pottery more susceptible to water damage.
Acrylic Or Water-Based Paints
If you’re already planning to transform your air-dry clay into a colorful masterpiece with paint, then acrylic or water-based paints would be a great option for you to add the element of water resistance.
While not strong enough to display outside without an additional sealer, acrylic paints work great for decorative pottery you plan to display inside your home.
The best part of acrylic paints as a water-resistant seal is that you get to add decoration and color to your artwork.
Since air dry clay can’t be used for creating kitchenware, it’s primarily made for artwork anyway. A great way to take that statue or decorative vase to the next level is to add beautiful design through color.
Acrylic paints are easy to work with, too. Simply grab a paint brush and get started. They dry quickly, so after already waiting 72 hours for your air dry clay to cure, you only have to wait another couple hours before the paint is dried and your art is ready to display.
2. Liquid Epoxy Resin
Liquid epoxy resin is by far the strongest water-resistant seal you can use for air dry clay. It will provide you with the most protection, but it’s also the most difficult to use.
We recommend liquid epoxy resin for those who are experienced in working with resin, or those who are looking to display their pottery outdoors and want a higher level of long-term water-resistant protection.
Always apply epoxy resin according to the package instructions. This will require some mixing and careful application, as well as a specific drying time. Read through the directions once completely before getting started on the process.
Make sure you have a clear and safe space to apply the resin and allow it to dry. The ideal space would be well-ventilated and away from any children or animals, like a garage.
Once you’ve applied your epoxy resin and allowed it to cure according to package directions, it’s safe to set anywhere inside or outside of your home.
Epoxy resin offers the highest level of protection, so any pottery sealed with this method will be safe to keep outside in any weather conditions – rain, sleet, or snow.
3. Mod Podge
For a lighter layer of protection, Mod Podge or any plain white glue will work great. We recommend the dishwasher-safe Mod Podge, but any will do the trick for light water-resistant protection.
We specify that Mod Podge should only be used for lightweight protection because it’s a thin layer of sealant and will not stand up against hard rainstorms. Mod Podge is best for pottery artwork that will be displayed indoors with little risk of water damage.
Although it offers lower protection, Mod Podge is great because it’s so easy to apply. Simply apply it to your pottery with a brush and allow it to air dry. Once it’s had time to fully dry, display it anywhere inside your home.
The Mod Podge will also give you a layer of protection in case you need to wash the pottery piece in case of spilled food or liquids or an accumulation of dust.
4. Tips For Applying Sealant To Air Dry Clay
Always allow your air-dry clay to dry completely before applying any of these sealants. Although your air-dry clay will feel dry to the touch after 24 hours, it’s best to leave it alone for 72 hours to allow for a full cure.
If you try to apply a water-resistant coating to your clay before it’s had time to properly dry, the clay will deform and lose its shape. You may find dips or cracks in your pottery.
When using varnish or resin, always work in a well-ventilated area with proper safety equipment. These types of water-resistant coatings can be toxic if inhaled for prolonged periods of time and should always be used with caution.
Do You Need To Seal Air Dry Clay Before Painting?
No, the paint will become the sealant for the air dry clay. For best results, use acrylic or other water-based paints. This will help the paint apply well to your clay and give it a nice finish.
You can always use an additional layer of sealant over the paint to give your pottery an extra layer of protection, but there’s no need for a base layer of sealant before painting.
What Is The Best Sealant For Air Dry Clay?
Liquid epoxy resin is the best sealant if you’re looking for a high level of protection. It will provide the strongest water-resistance and keep your pottery safe from outdoor weather damage.
If you’re looking for a sealant to use for an indoor piece of pottery, however, white glue or Mod Podge will be just fine. There’s no need for the high level of protection that outdoor pottery requires.
Varnish and acrylic paint are both solid options for indoor or outdoor display, though they are more of a middle-ground when it comes to sealants.
Neither of them will work as well as resin for outdoor use, but they’ll both provide a higher level of protection for indoor display.
The best sealant depends on your display area, so decide whether you’re going to set your pottery indoors or outdoors, then pick a sealant best suited for the environment.
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