Tag Archives: fun project

Outdoor School Mosaics

Recently I received an email from an art teacher whose school mosaic project was an outdoor mosaic where each child would create a mosaic on an 8 inch x 8 inch brick paver (paving stone), and then the mosaic pavers would be arranged together in a crazy quilt design similar to what artist Victor Kobayashi created for his mosaic patio in Honolulu.

I really like the crazy quilt approach to school projects because it allows each student to make their own art and have a real art experience instead of copying some teacher’s favorite piece of art, which usually involves more boredom or frustration than it does art. Crazy quilt projects also tend to produce more exuberant and impressive results. Copying something is merely copying something, even if that something is an acknowledged masterpiece.

Normally, school mosaic projects can use 1/2-inch or 3/4-inch sanded plywood as a backer, and the tile can be attached using a white PVA adhesive such as Weldbond, but plywood and glue are for indoors only. For outdoor and wet mosaics, you must use thinset mortar to attach the tiles to the backer, and that backer must be cement, stone or masonry. For large mosaics, a sheet of concrete backer board can be mounted to a metal wall using a frame welded from angle iron, or the mosaic can be created directly on a stone or concrete wall or a brick wall plastered smooth with thinset. In this case, the mosaic can be laid up in advance on fiberglass mesh, mosaic paper or clear mounting tape, and then these sheets can be pressed into thinset spread on the wall using a notched trowel.

This particular teacher decided to use brick pavers for her backers, but the concrete stepping stones/pavers commonly sold at building material stores could have been used in a similar way. The real issue for her project was how the students could use thinset mortar to attach each individual tile without creating a huge mess.

Thinset mortar is a sanded portland cement product with polymers added for strength and adhesive properties, so think of it as sticky concrete because that is essentially what it is. Your students might be mature and competent enough to use a bottle of glue that looks and handles just like Elmer’s glue, but how are they going to fare when they start working with sticky concrete? Now that I have your attention and your hair is standing on end, let me calm you by saying that it can be done, and it can be done fairly easily with a little forethought and planning.

One option would be to avoid setting each tile individually and lay up the designs in advance on clear mounting tape using my instructions for using contact paper and mounting tape. Then thinset could be spread on the pavers and the whole design mounted at once.

But that still involves handling thinset and some point, and sometimes you find situations where the mounting tape method isn’t practical (such as when not all of your tile have the same thickness).

Make A Prototype To Answer Basic Questions

The key too minimizing frustration and mess is to figure out your process BEFORE you involve the children, and the best way of doing that is to make a prototype in advance. In making a small mosaic beforehand, you work out the details of your materials and methods, including how the thinset will be distributed between the different children and how they will apply it to the backer.

Here are some questions you should answer by making your prototype. Please don’t let any of these alarm you because I have a practical recommendation at the end of this article that greatly simplifies everything and even eliminates some of these concerns:

How long does it take to apply tile to a mosaic of this size?

How many classroom sessions will be required?

Would it be more practical to have longer sessions instead of a larger number of short sessions?

How will thinset be applied to the stepping stones? Will the children spread the thinset themselves?

How will the children keep their hands clean while working; buckets of water and piles of rags?

How will we keep the thinset from drying out in the heated winter air or summer AC? Can we use humidifiers if necessary?

How much thinset do you need to mix up at one time? (This is answered by thinking about how many students will be working at once and how much thinset you used in one working session.)

How will we mix up the thinset? Is a parent volunteer available with a mixing paddle, drill motor and 5 gallon bucket? Do we have any parents who work as contractors and have experience with laying tile or mixing up concrete?

All of these things are relatively easy to implement, but they can make things chaotic or difficult if you don’t think about them in advance.

Thinset And Surfaces

There are a few specific concerns related to using thinset and pavers/stepping stones.

Surface Wetting

Sometimes you can drop a clump of thinset onto concrete backer board and it will harden without bonding to the backer board and it will fall right off or come off with minimal scraping. This was because the thinset didn’t really make intimate contact with the board due to surface dust. This can become more of an issue over time as you work and the thinset starts to set up as you are using it. The point is that sometimes you need to smear thinset into a surface to make sure it adequately wets the surface and makes intimate contact. Normally this happens merely by pressing a tile into the thinset, but you might do well to keep an eye out for students who are minimalists in terms of how much thinset they apply and for those who have a butterfly touch and just kind of sit the tile on top of the thinset instead of pressing it in.

Presealed Pavers

One problem you might encounter is pavers or stepping stones that have been sealed with some sort of silicon or polymer that might interfere with thinset bonding well to them. You can test for this simply by dripping some water or spittle on the paver and observing whether or not the water wets the surface. If the water wets the surface and soaks in, then there shouldn’t be any problem. If the water beads up similar to how water beads on a waxed car, or if it fails to soak in, then you know that the pavers have a heavy coat of sealant and should be avoided.

Skin Irritation

Wet concrete is mildly caustic, so it can dry and irritate the skin. A box of disposable medical examination gloves from the drug store can prevent this. You should also have the children wear safety glasses with side shields.

Overly Complex Designs And A Recommendation

Another thing you can learn from making a prototype is how much time is involved and how simple or complex the designs can be in order to be completed in the time allowed. I definitely prefer children be allowed to make original designs so that they get a real art experience, but you still need to give them recommendations about what level of detail is practical and look out for children trying to make overly complex and detailed designs. For this reason, it can be somewhat problematic for children to sketch out their designs in advance. Sometimes the mere act of drawing gets a person thinking in terms of a level of detail that isn’t practical in the medium in which the design will be executed. I have encountered this time and again while sketching out designs for my painting and mosaic.

Instead of sketching out designs, a more practical exercise might be for the students to play around with arranging tile before they decide on a finished design and definitely before they work with concrete.

I recommend making cardboard squares the same size as the mosaic backer and allowing the children to practice laying up their design on the square. If possible, give them one session to play with different arrangements and experiment with rendering different designs in the square, and a second session to finalize their design.

Then the following sessions could be about transferring the tile to the thinset on the paver. Using this approach, it would be possible for a teacher or parent volunteer to spread thinset on the pavers, and then the students merely transfer their tile designs from the cardboard squares/trays to the thinset, which would greatly minimize the amount time the children spent touching concrete.

A Practical Method For Kids And Thinset

  1. Make squares from cardboard that are the same size as the stepping stones/pavers or draw squares the size of the pavers on cardboard or trays. I prefer to cut out the cardboard squares so that they can be wrapped with contact paper with the sticky side out to prevent the tile from moving around.
  2. Have children spend one or two sessions arranging tile into designs on these squares/trays.
  3. Have teachers or parent volunteers mix up and spread thinset on the stepping stones.
  4. The children transfer their designs to the stepping stone one tile at a time. Alternatively, clear mounting tape could be used to pick up and transfer more complex designs made from smaller tile.
  5. After the thinset has hardened for a day, grout the mosaics with more thinset or grout.
  6. After the grout has hardened for at least a day or two, clean off any remaining grout residue by rubbing with a clean cloth and seal the mosaics with a tile and grout sealer.


The above instructions were written for children and beginners who just need to play around with tile to make simple designs. However, you may have more advanced students capable of making more sophisticated images from many small pieces of tile. I have written a second article Mosaic Transfer Instructions which explains how to lay up a more complicated design on a pattern and transfer it all at once to thinset or cement using mosaic mounting tape or clear packing tape.

Mosaic Coasters

Our shipment of hardwood bases for making mosaic coaster recently arrived, and I just now added them to our website. We have bases for making square mosaic coasters and round mosaic coasters, and these are great project ideas for someone wanting to make a mosaic miniature.

The coaster bases are made in the USA from cherry hardwood that has been cut out with a laser so that the sides have an attractive burnt wood finish.

mosaic coaster skull bases

The mosaic coasters are a great project idea because they are small and require less time and material. I made this skull mosaic the night before Halloween.

In the product descriptions for these, I included some instructions for how to make your own mosaic design on them. My instructions emphasize the need to evaluate your design to make sure you don’t have any details smaller than the smallest piece of tile you can cut. To do this, I always find the smallest detail in my design and cut up some tile and arrange it to form the detail. If I discover that it is too difficult to cut the tile that small, then I know I need to change the scale of my design by cropping it or simplifying it in some way. This is important for creating mosaic art in general, but it is particularly important when you start trying to make mosaic miniatures like this. It just doesn’t make sense to invest a lot of time in the rest of the mosaic only to get to the most detailed part (which is often a key focal point in the design) and discover that you can’t render it very well because it is too small.

Here is my mosaic skull coaster again. I am reluctant to describe it as micro mosaic because this is really nothing compared to the insanely detailed work that the micro artists turn out. After all, this is a coaster, not a design on a pinky ring!


Boo! In my painting and other mediums, I have been focusing on a series of small works as a means developing skills and experimenting with variations side by side. I can now see the advantages of using miniatures to develop skills in mosaic as well. It really does help to complete a piece with less time and materials so that you can try different approaches faster than you would if making full-sized works.

Mosaic Christmas Tree Ornaments

Please email us pictures of your Christmas tree ornaments made from our mosaic ornament bases. I would really like to receive a picture of one made to look like a globe of the Earth. I think a globe ornament would look spectacular, especially in mosaic, but I haven’t had the time to make one myself due to all my other art projects.

Remember to order your mosaic ornament bases early because we often get large orders from groups that completely exhaust our supply of hard polystyrene spheres.

mosaic ornaments

Mosaic Christmans tree ornaments made by artist Natalija Moss using our ornament bases.

Each ornament base is only 29 square inches (or 0.2 square feet) of surface area, so it doesn’t take too much tile to cover one. Just one bag of the 12mm Elementile Recycled Glass Mosaic Tile is more than enough to make an ornament. Depending on how you cut and space the tile, you only need between 100 and 125 tiles to cover one ornament, and each bag of 12mm Elementile contains about 185 tiles.

Mosaic Holiday Ornament Kit

I have designed a base kit that people can use to make a mosaic holiday ornament, and I plan to sell the base kit at the website. I designed the ornament base relatively quickly due to business demands, but I have spent at least 10 years thinking of how I would design mosaic kits or bases if I ever got around to it.

Design Criteria

Here are the criteria I decided were important for the holiday ornament kit:

  1. The kit should be only a base with instructions and not a complete kit because most people will want to pick out their own tile colors.
  2. The base should be reparable from generic components available at any hardware store.
  3. The mountings of the base should emphasize strength over shine or polish or decorative finish.
  4. The name of the ornament kit should avoid the word “Christmas” so that it could be used for other holidays and purposes year round.

Materials Used

The base is a 3-inch hard polystyrene foam sphere with mounting made from a loop of twine through a #8 stainless steel washer. The mounting is secured to the sphere using a 3-inch deck screw.

Note that the ornament does not hang perfectly centered from the string but is biased to one side, although the bias is slight. This was deemed preferable over a purpose-made ornament mount that would be perfectly centered yet not reliably hold the weight of a MOSAIC ornament.


The base is designed to hold the weight of a mosaic over the years without having the mounting pull free from the sphere. Thus the hardware used in the mounting emphasizes strength over decorative finish.

 Hard Polystyrene Foam Sphere 3-Inch

A wooded base would add too much weight. Styrofoam or foam of some sort was needed, but not the soft foam made for floral design. A hard foam of the type used for fishing floats was needed. I selected expanded polystyrene, which is hard and paintable, which means a white PVA glue such as Weldbond can bond to it. I chose a 3-inch sphere because that was roughly the most common size and shape of Christmas ornaments sold in the US, at least in decades past.

#9 Deck Screw 3-inch

A plain screw was chosen over an eye screw because eye screws tend to be too small or short or too heavy gauge. As far as what you can find in most hardware stores, there is no middle ground. A #9 deck screw has just the right pitch and thread length to grab onto the polystyrene. The 3-inch length was also optimal for the sphere size I had chosen. I used a deck screw because they are coated for corrosion resistance, and I wanted a fastener that could be re-glued in place if it failed years from now as the polystyrene fatigued from the weight of the mosaic.

#8 Stainless Steel Washer With Twine Loop

The #8 washer can accommodate a twine loop and the shaft of the deck screw yet not slip over the head of the deck screw. Stainless steel was selected for corrosion resistance.

Design Philosophy

There are all sorts of ornament mounts that we could have purchased from China that are purpose-made and shiny and all that. The problem is that the mounts made for Christmas ornaments aren’t made to hold the weight of a mosaic, especially over the course of years.
The hardware I selected to mount the ornament was based on strength and durability and repairability. After all, why does it need to be shiny and decorative if the mosaic underneath it will be shiny and decorative enough? Not only that, shouldn’t a hand-made ornament look hand made?

Field Reparable From Generic Components

If someone uses my base kit to make a family heirloom that is passed down generation to generation, the most important aspect of the base should be durability followed by repairability. After all, I didn’t want anyone to have to throw away their great grandma’s ornament simply because they couldn’t fix it.

When I was pursuing my first engineering degree, I worked an internship at an aerospace defense contractor so I could steal the plans for the death star and send them to the rebel alliance. (Actually I worked the internship because I was clueless in general, especially as to how I could ever figure out how to use an engineering degree to live the life I really wanted to live and make art full time.)

Anyway, while I was there I studied the military hardware doctrines of the Soviet Red Army and how they contrasted with that of NATO. While US designs for jets and tanks and other weapons systems were pushing the envelope in terms of sophistication and complexity, the Soviet design philosophy was more pragmatic: supply chains in times of war are easily disrupted, so don’t make anything that couldn’t be repaired in the field with generic components.

The ornament base I designed uses generic mounting hardware that could be easily sourced and replaced.

Failure Mode Effects Analysis

When teams of engineers are designing a new product in the corporate workplace, they do something called “Failure Mode Effects Analysis,” which is a study of how the product might fail in different ways and what the likely effects are of each mode of failure. For example, if the power switch for a vacuum cleaner shorts out, does the vacuum simply stop working or could it electrocute someone?

I applied this methodology to the mounting of the mosaic ornament and quickly rejected all the purpose-made ornament mounts I saw on the market. None of them seemed likely to support the weight of a mosaic. I also applied this principle to generic screws and hardware. If or when the mounting screw pulls out, I wanted a fastener coated with something that a white PVA adhesive such as Weldbond could bond to. That is why I selected a deck screw which has a corrosion-resistant coating instead of bare steel or zinc. Sure my fastener might pull out after years and years, but glue could be squeezed into the hole and the same fastener re-inserted.

Most Kits Discourage Original Design

Over the years, I have looked at craft kits sold for mosaic art with an eye toward selling them myself, but I have always been turned off in a major way by what I found. Every kit I saw on the market was overpriced, cheaply made and uninspired in terms of design, with a heavy emphasis on cutesy or being easy to complete in a relatively short amount of time. I considered designing my own project kits, but I didn’t want to do anything that encouraged people to make a copy of a design instead of making their own design. I started Mosaic Art Supply to encourage people to try their own hand at design and promote Art with a capital A, not sell junk to people who wanted to make junk.

I like the base kit I have made for a holiday ornament because other than size and shape, there isn’t any constraint on what type designs people could put on the base.


The base kit come unassembled so that the tile can be glued on and grouted without soiling the mounting hardware.