Thursday, July 5, 2012

How to Seal and Protect Painted Rocks

Painted rocks beg to be picked up and admired and by applying a sealant, the colors remain true and the life of the painted rock is extended.

A question I'm often asked is: "how do you seal your painted rocks." The quick answer: I use classic matte or gloss Mod Podge for sealing and protecting my painted rocks. (See my August 26, 2012 update below for a 2nd product applied over the Mod Podge to prevent "tackiness" in humidity.)


My much-used jar of Mod Podge

What is Mod Podge

Mod Podge is a non-toxic, nonflammable, water based:
  • Sealer that protects acrylic paint, decoupage, fabric, stain, etc. 
  • Glue that adheres, paper, fabric and other porous materials to almost any surface
  • Finish that's smooth, durable and fast drying

Why I Prefer Using Mod Podge on Painted Rocks

The Mod Podge formula is non-toxic, non-flammable, water based, and cleans up easily with just soap & water which makes it a great product for doing rock painting crafts with children. As an added benefit, I can also use the Mod Podge product if I wish to glue some type of porous embellishment onto the painted rock.

On the other hand, the clear, acrylic, protective finish available in a spray can (such as the Krylon brand) is toxic and care must be taken to keep the can away from heat and fire, don't puncture the can, ensure proper ventilation and avoid contact with eyes and skin.

While a sealer in a spray can might be easier to apply (especially to large painted rocks), I definitely want to use the safest product possible -- Mod Podge -- when doing my rock painting craft.

Update 5/22/2014: Learn about a low odor spray-on sealer for painted rocks.


How I use Mod Podge for Sealing Painted Rocks

I apply Mod Podge to all of my painted rocks (even the large outdoor garden decor and pavestone nativity sets) using a medium-to-large paint brush. Yes, it is a little more time consuming, but I love the feel of a brush in my hand and unlike the toxic alternative in a spray can, I don't have to ventilate my small painting studio.

I've used classic Mod Podge in both the matte and gloss formulas. The gloss formula is especially nice when a shiny effect is desired, such as when painting fish rocks.

Don't be alarmed when you open a jar of Mod Podge. It is white and looks like glue, however, it dries clear.


Other Mod Podge Formulas

I learned about other Mod Podge formulas in the recently published book, "Mod Podge Rocks" by Amy Anderson. If you'd like to try crafting with Mod Podge, Amy's book contains 40+ projects using the various Mod Podge formulas. Note: while none of the projects are related to rock painting, there are some clever ideas for using Mod Podge.

I plan to experiment on my painted rocks with these Mod Podge formulas in the future:
  • Satin - Between matte & gloss with a lustrous, soft finish
  • Hard Coat - Extra protection for projects handled frequently
  • Outdoor - Extra protection from moisture and elements
  • Sparkle - Has a hologram glitter for a rainbow effect. Makes projects glitter
  • Dimensional Magic - Thicker than other formulas, it adds extra dimension

Learn More About Mod Podge




Where to Find Mod Podge

I purchase classic matte and gloss Mod Podge at my local craft store, Hobby Lobby. It is also available in some Walmart and Jo-Ann Fabrics and Crafts stores.

Store locator from the Mod Podge manufacturer's website.


Mod Podge definitely rocks for 
sealing and protecting painted rocks.


   * * * Update August 26, 2012 * * *


A fellow rock painter recently faced a dilemma (or more accurately, a disaster) when she used Mod Podge on her painted rocks and stored them in a covered, plastic bin under the bed. When she opened the lid, many of her rocks were now stuck together and ruined.

It is believed that moisture and humidity do not like Mod Podge. The jar states "To eliminate tackiness apply Clear Acrylic Sealer over dried Mod Podge." Since I live in a very dry climate, I have not experienced this problem. However, I wanted to learn more about acrylic and polyurethane sealers.

Thank you, Lisa Carter, (another rock painting peer) who explained the difference between acrylic and polyurethane sealers.

"Acrylic sealer/finishes/coatings are considered single-component polymers...most are water based and provide waterproof protection on various surfaces ..they mainly enhance the color of painted surfaces and provide some durability. For the price..these work well for our painted stones ..especially those that are placed inside and will need protection as they are periodically dusted with damp cloths.

Polyurethane polymers are formed by combining two bi- or higher functional monomers. These are basically stronger and provide a more durable coating but are slightly more expensive."


Ceramcoat Satin Exterior/Interior Varnish

I purchased Ceramcoat Satin Exterior/Interior Varnish (the polyurethane product) and applied it over a few of my Mod Podged rocks. This is what I discovered:
  • This particular Ceramcoat product was twice the price of Mod Podge
  • The Ceramcoat varnish did have a slight ammonia-like odor
  • The product was a thinner consistency than Mod Podge so, even though more expensive, it should last just as long if not longer than Mod Podge
  • The rocks were now thinly coated with a sealer that was in between matte and gloss (which I liked)
  • The product is non-toxic, water based, and cleans up with soap and water.
I was pleased to further discover from Ceramcoat's Material Safety Data Sheet that:
  • Ceramcoat varnish can be used with general ventilation (no need to go outside or into the garage)
  • No known hazards from inhalation, skin contact, or ingestion. However, eye contact may cause reddening and tearing. 

* * * Update May 27, 2015 * * *


I have been extremely disappointed with the Delta Ceramcoat lately. It appears the company has changed hands and the sealer's formula has been altered. I now find the Delta Ceramcoat to be too thick and it has a strong odor.

My preference for a top coat sealer over the Mod Podge is Americana DuraClear Varnish. 

It comes in matte, gloss and satin, has a thin consistency and low odor.




I will be adding a final coat of polyurethane to my painted rocks on top of the Mod Podge as an extra layer of protection and to avoid stickiness.


Learn about a low odor spray-on sealer I'm using for doodle, tangle, and mandala rocks designed with artists pens.


Learn how to prevent Sharpie permanent marker pens from blurring when sealed.

47 comments:

  1. Very helpful information. Thank you.

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    1. I'm glad you found it helpful. Thanks for commenting.

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  2. I'm looking for a sealer for painted stepping stones. I've been using Ceramcoat internal/external varnish. I like it but I wonder how it will hold up in the elements. What do you recommend? There are people who would like to buy the stones but I want to feel confident that they will hold up. Thanks, Cindi Estess

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    1. Hi Cindi,

      For my outdoor rocks, I've been using Mod Podge Outdoor as a first coat of sealer followed by several coats of the Ceramcoat varnish. The Mod Podge goes on thick (a good thing?) but is sticky when dry. The stickiness isn't an issue because several coats of the Ceramcoat go over it.

      For the stepping stones already painted, I would add several coats of the Ceramcoat varnish (at least 3) and tell your buyers to check the stones yearly for signs of wear and to apply additional sealer if needed. For yearly maintenance, I'd recommend one of the spray-on sealers by Krylon. To make it easy for your customers, you could include the spray-on sealer with your sale or provide them with the product name and where they can buy it themselves.

      For future stepping stones, I would paint them with acrylic paint specially formulated for the outdoors (Deco Art Patio Paint or Anita's Yard & Garden) and follow up with several coats of the Ceramcoat varnish. Once again, your buyers will need to check the stones occasionally and add sealer if needed.

      Hope this helps. It's hard to say how rocks will hold up outdoors because the weather is so varied. Where I live, we don't get much rain or snow but the sun is brutal.

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    2. Hi Cindi,

      Where can you buy the Americana Duraclear Varnish?

      Thank you,

      Sheri

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    3. Sheri, I purchased my Americana Duraclear Varnish at Jo-Ann Fabric and Craft Stores. It should also be available at Michael's, Hobby Lobby, Amazon and possibly Walmart.

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  3. Do you bake the sealant after applying?

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    1. No, I just apply the sealant and let it dry.

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  4. When you apply the sealer (Mod Podge) to the painted rocks, where/how do you place the rocks to dry?

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    1. Where I place the rocks to dry all depends on the shape and size of the rock. If the rock stands upright on its own, I use a lazy Susan and spin it to seal each side of the rock and allow it to sit on the lazy Susan for 15-30 minutes to dry. I then place the rock on its side and do the bottom.

      If the rocks are flat, I'll seal one side and allow that side to dry then flip it over and do the reverse side. I've also used egg cartons as a drying rack. I'll seal the top of the rock and sit it in the egg carton, sealed side up. Once that end is dry, I'll flip it over and do the other end.

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  5. I was told today from the makers of Mod Podge outdoors that it has to CURE for 4-6 weeks before covering them with a sealer for outside it that the case? I am so upset that the product says 72 hours not 4-6 weeks.

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    1. I never heard that Mod Podge outdoors needs to cure for 4-6 weeks. My bottle also says the item should cure 72 hours before placing outdoors. But, even with a sealer, a painted rock may fade over time when it is exposed to harsh weather and will need to have the sealer added again and sometimes the paint retouched.

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  6. I am looking for help. First time at rock painting. Painted decoration on a bare rock with Sharpie oil based paint pens. Waited 20 hours and sprayed with Krylon sealer. The Sharpie colors ran! Also, it did not really seem to give the rock a glossy finish.

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    1. I'm sorry to hear your first rock painting project was ruined with the sealer. I don't use Sharpie paint pens (oil based) very often because I'm never sure if they will bleed or not. Did you spray thin coats of the Krylon sealer? Many thin coats are better than one thick coat which would cause the pens to bleed. As for the glossy effect, I know the brush-on sealers come in different formulas - matte - glossy - satin. I'm not sure if the sprays do. For a glossy finish you would want a spray marked as such.

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    2. Thank you for your reply. Yes, it was only a bare wisp of the sealer and the paint immediately bled. I was using the pens because I figured it would be easier than brushes as a starting project. Live and learn, I guess. Can I just paint the whole rock a dark color and start over?

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    3. I've been searching for the perfect pen to use on rocks, Denise, and haven't found anything which works perfectly. If you practice and practice with brushes it will get easier. YES, you can paint the whole rock and start over! That's the good thing about painting rocks. Here's how I re-did some rocks I wasn't happy with: http://paintingrocks.blogspot.com/2013/10/do-over-painted-rocks-or-how-to-re.html

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    4. Iuse sharpie pens on gourds. They need to fully dry for at least a week prior to spraying them. For the first coat. I lightly dust it with spray and let. Each coat of clear spray dry overnight. It takes time but the ink does not bleed , it did when I was in a rush and didnt wait though.

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    5. Thanks for your comment, Rinda. Impatience may be my problem with Sharpies. I want to spray seal the rock shortly after I've used the Sharpie. Next time, I'll wait at least a week to see if that makes a difference.

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  7. mod podge is multipurpose, but i found it hard to dry, it's almost sticky when i put a surface that sealed with mod podge on the others . Do you have any solution? Sorry for my English.

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    1. Mod Podge will be sticky if you live in a climate with high humidity. You may have better results with a spray sealer such as Krylon Crystal Clear Acrylic Coating instead of Mod Podge. You could also try the Delta Ceramcoat Varnish or DuraClear Varnish alone or a mixture of both. Some rock painters have used sealers meant for waterproofing boats but I have no experience with those. P.S. Your English is very good!

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  8. thank you, i live in Viet Nam, a tropical country and i think that's why. Maybe i'm try to mix some stuff to find out. Your blog is very useful for me :)

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    1. I'm glad to hear you find the blog posts useful. Don't be afraid to experiment with sealers, paints and techniques. What works for one person may not work for another as you've seen. Happy rock painting!

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  9. Thank you for the tips! I will be trying out the Americana Duraclear varnish. I have river rocks where I had family and friends write a word, phrase, short memory of my nephew that passed earlier this year. I will be presenting the rocks to my sister and husband and let them know that there are many of us who love their son, and is represented by the rocks (solid love). So the river rocks can be placed near their door, so they can read a rock every time they leave the house..or they can leave the rocks at his gravesite or even at their garden. I heard about painting on rocks and thought it was a great idea, and was worried about the artwork/words coming off. So I'm glad there is a blog like this...thank you!!

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    1. You're so welcome. I'm so sorry to hear your nephew passed and really like your idea of writing on the rocks as "solid love" to remember him. If the words are written on the stones with a Sharpie pen, I would advise using thin coats of a spray-on sealer instead of the Americana Duraclear brush on version. Sharpies are known to smear when a sealer is applied and I'd hate to see all the loving words your family and friends have written get ruined. (You may want to try a test rock before using any type of sealer, especially since your stones are so important.) FYI - A sealer applied to rocks is weather resistant but not weather proof. You need to check the stones and occasionally apply more sealer otherwise there's a chance the words will wear off.

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  10. Hi! Thank you for your info. I also had words written with sharpies for a memory and wondering if I can use mod podge and a spray sealer. Id like them to hold up being outside in California weather. Can I use outdoor mod podge? Also, what spray on sealer do you recommend? Thank you so much!

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    1. Hi Ryan. If you used Sharpies, I'd make my first coat of sealer a light application of a spray-on type. Yes, you can use both Mod Podge (outdoor is OK) and a spray-on sealer together. No sealer will protect the rock permanently from the weather but the more coats you apply, the better. Occasionally you may need to apply more sealer. My preference for a spray-on is Krylon Low Odor Clear Finish because I spray the stones in my garage and don't like the high-odor forumlas.

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  11. I'm painting a very large rock at the end of my driveway with my house number. What sealant would be good for that application? Thank you in advance!

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    1. Heidi, since you're painting a large rock which will be sitting outdoors, my suggestion would be to check with the paint department in a home improvement store for their advice. They have knowledge of the various sealers and would be familiar with the best one for the rock's qualities. In my experience, no sealer will permanently protect your outdoor art and it is necessary to reapply the sealer every so often if the design begins to fade. The sealers mentioned in this post would work temporarily but I don't think they'd be the best solution.

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  12. Thank you for this article. Just wondering if anything would be able to seal a painted rock if it were living in water. Something super waterproof. Thanks. :)

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    1. You're welcome, Andi. If you want a painted rock to be super waterproof, a sealer used for a boat might be a product which could work.

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    2. Okay, thank you so much, Cindy!

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  13. Any suggestions for sealing small to medium smooth rocks from the ocean? I used Modge Podge and it definitely dulls the colors! Very disappointing but maybe I used it too soon after using Sharpie markers and Gelly Roll bright colored markers. Thanks!

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    1. Donna, you may have better luck using a spray-on sealer since you're using markers on your stones. Markers are notorious for reacting negatively with sealers. You'll want to spray several light coats of the sealer on the stone and let it dry completely between applications. Here's a blog post I wrote about the spray-on sealer I prefer: http://paintingrocks.blogspot.com/2014/05/a-solution-to-smell-and-mess-of-spray.html

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  14. Cindy, if I am going to be having my rocks outdoors, would I use outdoor modge podge and then the americana sealer over the top? I am making a set of painted rocks for my grandmother, and I would really like to shy away from toxic chemicals.
    Thank you,
    Patience S.

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    1. Patience - Yes, I would use the outdoor Mod Podge on the painted rocks first followed by 2-3 coats of the Americana sealer. Even with all those applications of sealer, the rocks may still need to be "touched up" occasionally with additional sealer if the weather is extremely harsh. (No sealer will permanently protect the painted stones.)

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  15. I want to use small stones that could be carried in pocket or purse and I sure don't want them to be sticky.

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    1. I learned the hard way about sticky rocks. I would mail rocks using tissue paper as a wrapping. Because Mod Podge alone is "tacky" the tissue paper adhered to portions of the painted rock. For your pocket/purse rocks, make sure the sealer(s) have completely dried.

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  16. Yes! Very bad experience with clear spray and sharpies! Took 4 days to paint my ocean scene..and was ruined the second the spray hit it :) luckily...I painted the running paint the best I could. Mind you, doesn't seem like I'm using the right clear coat! I grabbed tremclad clear coat that was in my closet.. It's actually working rather nicely if there isn't a trace of sharpie! Although I am finding that it drips around edges so I am preventing that by using very thin coats.

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    1. Sharpies are notorious for bleeding/blurring when sealed, Shawna. Thin coats of a spray sealer definitely are better. I have recently learned that applying a coat of white glue (e.g., Elmer's) over Sharpies prevents sealer mishaps. You can read more about my experience with glue and Sharpies here: http://paintingrocks.blogspot.com/2016/12/how-to-prevent-sharpie-permanent.html

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  17. lindagrow24@comcast.netMarch 28, 2017 at 5:38 PM

    do you need to seal a rock before you paint?


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    1. Lindagrow24 - You do not need to seal a rock before you paint it. However, giving the stone a base coat of white acrylic paint makes the subsequent colors brighter. And if your rock is super smooth a sealer or base coat may help any subsequent paint adhere better.

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  18. I used a white school glue to seal the rock then used sharpies...sometimes I seal
    L with the glue again...or nail polish..or a spray on sealer.No bleeding...

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    1. Thanks for your comment, Teeli. I recently discovered how well white glue works with Sharpies and paint pens. I haven't had much luck with the nail polish though. http://paintingrocks.blogspot.com/2016/12/how-to-prevent-sharpie-permanent.html

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  19. Cindy in your experience is it neccesary to put Gesso or anything else before painting a rock with acrylic painting, what thing would protect the cracking paint over years? Im wondering what would happen years later comparing it with techniques used to paint over wood or a wall.sorry for my sudamerican english, hope you can understand. Thanks!

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    1. Mariarosabb - In my experience, it is not necessary to apply Gesso or anything else before painting on rocks with acrylics. (Occasionally, I'll use white acrylic paint as a base coat to make the colors appear brighter.) I have been painting rocks for 10 years and have not experienced cracking paint when the rock is sealed and kept indoors. However, if the painted rock is displayed outdoors, the hot sun and inclement weather may affect the paint finish even though the rock has been sealed.

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  20. Thank you very much Cindy! I was worried about my first rocks painted. As i live in a hot weather with humidity im not sure about using mod podge reading some comments here, i bought a wood sealer but it doesnt mention if it is waterbased or if wood sealers are multipurpose for acrylic and oil painting, Im not sure if it will be save to use it or if i must look for a waterbased sealer.

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    1. You're welcome, Mariarosabb. You're correct - because you live in a hot and humid climate, the Mod Podge will not be a good sealer for you. It is not necessary to use a water-based sealer and your wood sealer may be fine. Much of rock painting involves experimentation so you may need to try various sealers before you find one to meet your needs. I'm sorry I can't be more specific about a sealer. In general you want a clear coat of protection that does not blur or ruin your painted design.

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