How To Seal Painted Rocks For Outdoor Protection

Rock painting is an incredible activity for all ages. Each summer, my family collects rocks from the beachfront and we paint them. Over the years we've painted butterflies, inspiring quotes, and mandalas. But if you leave them outside for even one Chicago winter, the paint might peel or chip. This is why it is important to add a layer of protection. Sealing rocks for outdoor protection is essential to maintain their appearance and durability against the elements like snow, hail, rain, and wind. Proper sealing will extend the life of your painted rocks.

Materials Needed:

Sealer: Choose a sealer appropriate for your specific rock type and intended use. (we will cover the different choices below)
Cleaner: Mild detergent or stone cleaner to remove dirt, oil, and stains from the surface.
Brushes/Rollers: Depending on the sealer type, you may need brushes, rollers, or sprayers for application.
Protective gear: Gloves, safety goggles, and a mask to protect yourself during application. This is especially necessary if you are using sealers with sprayers or sealers will a strong odor.
Applicator Pad or cloth: For wiping excess sealer and achieving an even finish.
Drop Cloths or tarps: To protect surrounding areas from drips and spills.
Scraper or putty Knife: For cleaning and scraping off debris from the rocks.
Sandpaper or wire Brush: To smooth rough surfaces or remove loose particles.

Steps to Seal Rocks for Outdoor Protection:

Step 1: Preparation

Clean the Rocks: Ensure the rocks are clean and dry before applying any sealer. Use a brush or scraper to remove dirt, moss, or any other debris. Wash the rocks with water and a mild detergent or stone cleaner to remove oils and stains. Rinse thoroughly and allow them to dry completely.
Inspect for Damage: Check for cracks, chips, or areas of erosion that might need repair before sealing. Fill any cracks with appropriate sealant or epoxy and allow it to cure completely.
Smooth Rough Areas: Sand rough or uneven surfaces with sandpaper or a wire brush to create a smoother finish.

Step 2: Choosing the Sealer

When it comes to sealing rocks, the purchase will be dependent upon whether or not you want to have the rocks outside for a long time or just a few days. Do you want shiny rocks or for it to look more like a natural stone?

Options include acrylic sealers (water-based or solvent-based), penetrating sealers (silicone or siloxane-based), or polyurethane sealers. Consider the sealer's durability, UV resistance, and breathability (especially for natural stones).

I also like to consider whether or not you are working with kids or if this is for adult use only. The toxicity of some sealers is not the best choice when crafting with kids.

When choosing the right sealer, you will want to consider how much the painted rocks will be exposed to the elements - especially sunlight or excessive moisture. You also want to be sure the sealer won't be yellow if left in the sunlight. Here are the sealers that have worked best for me:

1. Mod Podge: this is my go-to choice when working with kids. I like that it works on rocks, concrete surfaces, and landscape rocks. Mod Podge comes in a shiny and matte finish and can be watered down and made into a Mod Podge formula. I added the Mod Podge formula to a spray bottle to create a spray sealer.

As a general rule, Mod Podge works best on landscaping rocks if you use a minimum of two coats since the rocks are porous. I like that Mod Podge comes in matte finishes, satin finishes, and gloss finishes. There are a lot of different options which makes it a great acrylic sealer. It can also be found at any local craft store.

Mod Podge does have a bit of odor but you don't need to use Mod Podge outdoors which is nice. You will want to work in thin layers. You can often find Mod Podge in the dollar store.

2. Dura Clear: This is a great product that is also good for use with kids. It is high-quality but not too expensive. This sealer is best used as a paint-on sealer. I love that it is odorless. You can add a little water to thin it out if you feel there is too much sealer or the coat is too thick.

3. Rustoleum spray: I love using the Rustoleum spray when making rocks for myself. If I am painting rocks, I will add this sealer as a final step. I like this sprayer because the sealer sprays evenly and I like how it gives the rock somewhat of a wet look.

You will want to be sure to apply the Rustoleum in a well-ventillated room since the smell can be somewhat toxic.

4. Krylon Clear UV Coat: This is a high-quality sealant and can be found at most craft stores like Michaels, Blick, and Hobby Lobby. I have also seen these available at the hardware store Lowes and Home Depot. I like using this clear coat when my rocks will live in a sunny location because of the UV filter.

This spray works as a gloss varnish and is a popular craft supply for a variety of projects. I love how this spray has a consistent speed and builds up with several layers.

5. Deco Art Triple Thick: This is my go-to varnish when I am looking for the type of sealer that has a very high gloss finish. I love the way these gloss formulas shine on a black river rock.

6. Clear Casting Resin: I love using clear casting resin because it makes it completely water resistant. I have found, however, that it does tend to yellow over time. It gives the best transparent gloss seal, however, resins can be toxic and should only be used according to the manufacturer’s instructions and in a well-ventillated room.

As always, do your own testing and try a light coat of sealer on the back of the rock just in case.

Step 3: Application

Apply the Sealer: Follow the manufacturer's instructions for the specific sealer you've chosen.
Even Coverage: Ensure the sealer is applied evenly to avoid streaks or patches. Work in small sections to manage applications and ensure thorough coverage.
Multiple Coats: Depending on the sealer and manufacturer's recommendations, apply multiple coats for optimal protection. Allow each coat to dry completely before applying the next. If you pick the right day to spray and the sun is shining, you can add a second coat to the surface of the rock within 10-15 minutes.

Step 4: Drying and Curing

Dry Time: Allow the sealer to dry completely between coats and after the final application. Drying times can vary based on environmental conditions such as temperature and humidity.
Curing Time: Follow the sealer manufacturer's guidelines for curing time before exposing the rocks to moisture or heavy use. Curing times typically range from 24 hours to several days.

Step 5: Maintenance

Regular Cleaning: Keep sealed rocks clean by regularly removing dirt and debris. Use a gentle cleanser or stone-safe cleaner to avoid damaging the sealer.
Inspect and Reapply: Periodically inspect the sealed rocks for signs of wear or damage. Reapply sealer as needed to maintain protection, especially in high-traffic or exposed areas.
Avoid Harsh Chemicals: Use cleaning products that are safe for sealed surfaces to prevent damaging the sealer over time.

Final Thoughts

Sealing rocks for outdoor protection is a practical way to enhance their appearance and durability while safeguarding them against weathering and stains. By following these steps and choosing the right materials, you can ensure that your outdoor rocks remain beautiful and functional for years to come.

Proper preparation, application, and maintenance are key to achieving optimal results with sealing, ensuring your outdoor rocks withstand the elements and retain their natural change.

Painting rocks for the first time? Don’t forget to read my beginner’s guide!

How To Seal Painted Rocks For Outdoor Protection