Air-dry clay is a wonderful medium to work with. It acts much like potters clay but doesn’t require firing to be hardened. The one major issue with air-dry is that it is very sensitive to moister even after it has hardened.
If you want your work to have any permanents, you will need to seal it against the elements. There are many different sealants for air-dry clay on the market and they come in many different types.
To help you preserve your air dry clay creations we present you with this guide to sealing air dr-dry clay. We will also offer some advice on choosing the best sealer for your projects and answer the most commonly asked questions we hear on the subject.
What to Look for in an Air Dry Clay Sealant
Air-dry clay doesn’t have to be sealed unless it is going to be exposed to moister. Many artists actually like the chalky look most air-dry clays have.
However, if you are going to be cleaning your work with damp rags, placing it outdoors, or you live in a humid climate then it is advisable to apply a sealer to prevent your projects from degrading over time.
There are many options available to seal air-dry clay. To help you find what will work best for you, here are the four main areas you should think about before deciding which to buy.
The first thing to think about when picking a sealer for air dry clay is how and where it will be used. As an example, if the piece is going to be where it will be exposed to the elements then you will likely want to stick with either epoxy resin or polyurethane varnish. These two options are both waterproof and neither will yellow over time.
There are some acrylics that will make your clay water resistant but not waterproof. These work well in humid climates but many will cloud if left exposed to water for too long a period of time. Mod Podge also makes a dishwasher-safe sealant that is reportedly waterproof, but we haven’t tried it ourselves so hesitate to recommend it.
If you are going to be displaying your air-dry clay pots and statuary indoors you can pick almost any sealant including PVA glue (white glue)
One word of caution if you are going to be creating a candy dish or similar item be sure the sealant you pick is certified food-safe.
When buying a sealer for air-dry clay you have several options available. The most commonly seen being;
- Semi-gloss (Satin)
- Semi-Matte Finish
You will see other names used from time to time but they are basically marketing terms for these same finishes.
The exception to this is the opaque and tinted sealants that are available, Some of these can be quite stunning and might suit your taste.
The look that will work best for your projects is purely a matter of taste.
You have three basic options when you seal air-dry clay. You can brush on the sealant, spread it with a sponge, or use a spray-on varnish. There are pluses and minuses to all three methods and the best to use is largely a matter of taste.
However, you will find that the various application methods do lend themselves to being better for sealing some shapes over others. Here is a brief breakdown of the methods we feel work best to waterproof air dry clay.
When varnishing flat pieces, our choice is most often spraying. Once you develop the technique it is really fast and easy to do. The secret is using long sweeping strokes.
If you have lots of details or nocks and crannies spraying is a less satisfactory method. Unless you have a lot of experience, some spots will inevitably be missed, and often runs and drips will develop.
All types of finishes can be applied with a sponge. We like this method for projects that have flowing lines and organic curves. It works best with thinner sealers that absorb well into the sponge and flow evenly.
This method is a little messier than brushing or spraying so remember to wear gloves or use the sponge brushes that have become so popular of late.
To make air-dry clay waterproof brushing on a sealer is the most versatile method to use. Brushes come in a never-ending variety of shapes and sizes. They can be used to quickly seal air dry clay whether it has large planes or fin details.
For large areas, wide brushes can be used and small details can be just as easily coated using smaller brushes. Brushes can also be used with any thickness of varnish or sealer.
As a general rule, sealing air dry clay isn’t an expensive proposition but prices do vary from one product to another. As you might expect, price follows the performance, and the more you are able to spend the better protected your air-dry clay projects will be.
The most expensive sealants for making air-dry clay water-resistant are epoxy resins. In fact, they don’t just repel moister they are waterproof. When you also consider that they are also resistant to impact, UV rays, and abrasion it is easy to understand why they are worth the cost.
Slightly less expensive than epoxy coatings are polyurethane varnishes. These are the sealants that we use most often and the choice of many professional crafters. They are not quite as durable as epoxy but some come very close. They are also much easier to apply as there is no mixing involved. Polyurethane can be bought as a brush-on liquid or a spray.
After polyurethane water-based varnish comes acrylics. Acrylics are great for projects that will be displayed indoors and are not likely to receive many bumps. It is also ideal for earrings and similar crafts that may be exposed to skin oils but little else. Many tend to cloud if exposed to moister and they may yellow over time. They are very economical though.
The cheapest route of sealing air-dry clay is to use a PVA glue or similar product like Modge Podge, You can use common white school glue. It can be thinned using water to make it easier to apply. While inexpensive and certainly easy to find, the protection that white glue provides is minimal at best.
One last category is company brand sealers. Depending on the company and product their prices can vary greatly as does their quality. As these are proprietary mixes normally designed to be used with specific clays. You will have to make your own determination as to how well they will suit your project and if they are worth the cost.
How to Seal Air Dry Clay
It is a fairly simple process to seal air dry clay. Most anyone including a complete novice can master the process. very quickly. To help assure you have great results from your first project to your last we offer this short set of instructions for sealing air dry clay.
- The first thing is you can’t rush the drying of your clay. Our best advice is to allow your air-dry clay projects to dry according to the manufacturer’s recommendations and then give them an extra 24-48 hours to make sure it is completely dry.
- Next, examine your project closely. Any rough areas or blemishes on the surface should be carefully sanded smooth. Many sealants will highlight any imperfections you leave behind. Also, be sure to remove any dust you create while sanding.
- Use coins popsicle sticks, little balls of clay, or other objects to slightly elevate your project from the working surface. You don’t want to seal your clay and then realize you have glued it in place.
- You can now apply your first coat of sealant. If all you are wanting to accomplish is making your air-dry clay waterproof, then one coat may be enough. The purpose of this initial layer is to fill and seal all of the pores in your clay work. Unless you are using epoxy resin as a sealer, it is best to apply as light a coat as will provide complete coverage.
- Let this initial coat dry and inspect it for any problem areas.
- Correct any flaws that you find now. It will be much more difficult to take corrective action later.
- If everything looks good you can continue to add layers of sealant till you get the look you are looking for. It is generally a good idea to apply at least three coats of sealant to avoid leaving any thin spots. Don’t rush this phase and only add additional layers according to your sealant’s directions.
- Leave your work in a warm room that is not exposed to too much sunlight and has as little dust as possible. Again, be patient and allow your work to completely cure before handling it unnecessarily.
As a general rule, multiple thin coats are better than thicker coats. In fact, some sealants like many of the clear acrylic sealants will cloud or become tacky if too much is applied in a single layer. It is better to invest a little more time in sealing your air-dry clay than to rush and ruin all your work.
Can Air-Dry Clay be waterproof?
Yes, you can waterproof air dry clay. All that you need do is to apply a coat of an appropriate sealer. Our personal recommendation is to use either epoxy resin or polyurethane varnishes. Epoxy sealants are more durable but both are available in waterproof formulas and are fairly easy to apply.
Does air-dry clay need to be sealed before painting?
No, you do not have to seal air-dry clay before you paint it. Most paints, including acrylic paint, will adhere to air-dry clay as long as it is properly cured before being painted. Many sealants will even allow you to apply paints in between layers of sealants. This makes it possible to create some truly unique and stunning effects.
Does acrylic paint seal air dry clay?
Acrylic paint will seal air dry clay but only to a certain extent. Most acrylic paint is water-resistant but will not make your air-dry clay pots waterproof. Unlike polymer clay, air dry clay is water-soluble. To be made waterproof it has to be completely coated with a waterproof coating like epoxy or polyurethane. Most Acrylic paints, including outdoor acrylics, are water-resistant not waterproof.
Will Air-Dry Clay dissolve in water?
Air-dry clay, whether dried or in a workable state is water-soluble. That is, it will dissolve in water. Even humid conditions can cause them to deteriorate over time. To have any permanents, air dry clay should be sealed with an appropriate water-resistant sealant. These can range from the completely waterproof epoxy coatings on the market to watered down PVA glue (white glue)
Is air dry clay food safe?
Air-dry clay is not food safe and it should be used for decorative purposes only. There are some sealants available for air-dry clay pots that are food-safe, but even if these are applied we would not recommend using air-dry clay for eating or drinking.
Can you wet air-dry clay while sculpting?
Yes, you can add water to air-dry clay while sculpting it. Just as you would with ceramic clays you can add small amounts of water using a sponge, your fingertips, or by dipping your tools in water. This makes the clay more pliable and easier to shape. You can also dissolve a small amount of air-dry clay in water and use it as an adhesive for attaching additional sections to a work or as a crack filler.