Category: Joe’s Rantings
Mosaic Artist Michael Kruzich has a body of work worth taking a look at, especially if you have any doubts about how well dramatic lighting can be rendered in mosaic portraiture and other figurative mosaic artwork.
But that’s not all that you need to see of his work. Michael has also made some mosaic-clad figurative sculpture that is as interesting in it’s abstract geometrical textural elements as it is in it verisimilitude –plus he has some stylized, classical and medieval interpretations. These stylized pieces are as eye catching as Michael’s naturalistic work. The reason is simple: All of Kruzich’s mosaics make great use of contrasting light and dark elements in addition to using strong pairs of complementary colors.
Figurative mosaic art (mosaic pictures) can be used as an element of interior design in the same way that paintings are used. The only difference is that a stronger, more secure way of mounting the artwork to the wall is needed.
Natalija wrote an article about using a French cleat mounting system to securely hang a mosaic if you need more information about how to do that, and I discuss some concerns about using picture wire toward the end of this article, but first I want to talk about aesthetic considerations and how to make sure a mosaic looks right in a room.
A few years ago, Karen J created a mosaic bench in her backyard using mining debris (large stones), cement, and chicken wire to form the base, which is similar the methods we recommend in our instructions for creating bases for outdoor mosaic sculptures. Karen modeled her bench after those made by the great mosaic architect Gaudi in Park Guell in sunny Barcelona, and she used brightly colored ceramic tile just as Gaudi had used. The problem is that Karen’s backyard is in Colorado, and so her mosaic experienced many long and hard freezes that a mosaic in Barcelona would never see.Mosaic Bench after Antoni Gaudi shows the ravages of freeze damage. Colorado winters are quite severe, but any temperature below freezing can crack and flake ceramic tile. Ceramic Tile Is Vulnerable To Freeze Damage
Glass mosaic tile is non-porous, and so water cannot seep in and freeze and crack it, and so glass is preferred for outdoor use, as is porcelain tile for the same reason. On the other hand, ceramic tile tile is very porous and soft, and so water can penetrate it (through tiny cracks in the glazing). Once this water freezes and expands, it cracks the ceramic tile and often causes the face of the tile to flake off.Mosaic Bench Detail showing freeze damage. Note that the empty sockets in the blue tile are NOT where tile has popped off. Instead, it is where the faces of the tiles have flaked off due to water freezing and expanding in tiny cracks and pores.
In the photo above, you can see how some colors were more resistant to freeze damage than others. This difference was not due to the color but to the variety of the tile: some brands of ceramic are harder and less porous than others. Also, some brands have thicker glazes, and that can also affect how permeable the tile is to water.Preventing Freeze Damage
You can minimize freeze damage by sealing your finished mosaic with multiple applications of a tile and grout sealer from your local building material store. Avoid ordering sealers online during winter months because water-based silicone sealers ruin if they freeze during shipment. You should also clean and reseal the mosaic each fall. Small mosaics such as mosaic stepping stones can be brought inside for the winter.Mosaic Bench Second Detail showing freeze damage. Imagine how bright the orange and yellow sun was before Freeze Meister blasted it and flaked off the color!
Mosaic Fireplace and Oven Surrounds: The Basics
A couple of years ago, I wrote a page explaining how glass, ceramic, and stone tiles can be used for mosaic fireplace surrounds and how the tiles should be mounted with thinset mortar or white PVA (polyvinyl acetate) adhesives such as Weldbond. But we are talking about the SURROUNDS, not inside the firebox. For inside the firebox, your need to use refractory materials (brick or stone) that can resist combustion temperatures. For the hearth, the issue is not temperature resistance so much as impact resistance: It doesn’t make sense to use glass tiles that are easily cracked by a metal poker or small tiles that are easily knocked loose. Stylistic concerns should never outweigh performance and durability, else the work won’t look good for long.Mosaic Pizza Oven by artist Kristina Young with octopus tentacle motif. Seafood and sea life and undersea scenes were common themes of Roman mosaic. Problems with a Mosaic Pizza Oven
Recently, artist Kristina Young emailed me concerning a problem she was having with a mosaic she installed on the outer surface of an Italian pizza oven. The problem was that the mosaic was cracking over the door of the oven, and that caused me some concern because that should not happen with traditional fireplaces and pizza ovens constructed with brick or stone, and I have been telling people for years that there was no reason why they could not put mosaics on these surfaces in spite of the heat. Had I overlooked some basic technical principle and made recommendations that could ruin hundreds of people’s projects? The engineer in me became completely paranoid, and I could not wait for Kristina to email me back with answers to my initial questions.
Spoiler Alert: The good news is that the cracking is reparable and that the cracking is by the iron frame of the oven door, not the masonry elements of the oven itself, which means that there is no reason to expect similar problems with traditional fireplaces and ovens that are made from all stone or brick or concrete.The Case of the Cracking Mosaic Detail shot showing crack in brand new mosaic covering the exterior of masonry pizza oven. The location of this crack is significant: It started right above the iron frame of the oven door.
When Kristina first contacted me, she was concerned that the cracking might have been caused by heating the oven not long after the mosaic was completed. That is a potential issue because thinset mortar takes time to harden, and like concrete, it hardens by bonding moisture not by drying out. (Concrete, mortars, grouts, and other portland cement products will be soft and crumbly if they are dried out by heat or dried air. They need to incorporate the water mixed into them, not have it removed artificially.)Humidify, Don’t Heat
I don’t think that the oven was heated prematurely or that premature heating caused the cracking. The crack is location specific, and if the mortar was artificially dried out before it could harden, then the problem would be seen all over the mosaic in the form of cracks and missing tiles. That being said, I would avoid heating fireplaces and ovens for several days after a mosaic has been applied to them and grouted. The usual practice is to run humidifiers near a new mosaic to protect them from AC or central heat –not build a fire under them!Thermal Expansion
Except for the notable exception of ice, most materials expand when they are heated. (Water expands when it freezes, and that is why ice floats: it is less dense than the water beneath it.) The problem with thermal expansion is that materials expand at different rates, and metals like iron expand more rapidly than stone, brick, and concrete. Kristina had already told me that the crack started on the front of the oven just over the door, and so as soon as she sent me a picture of the oven showing that the door had an iron frame, it was obvious to me why the crack had started there: The glass and mortar mosaic expands at roughly the same rate as the brick and concrete oven underneath it, but the iron door frame and the other iron structural elements expand even faster. They push the mosaic up like a shell on the outside of the oven, and when the oven and frame cool back down and contract, the crack appears.The Right Repair Materials
An “expansion joint” spontaneously forming in the middle of your mosaic might have most people panicking and thinking of repairing the crack with a flexible material such as caulk. Caulk is problematic because it will not age well. It will yellow and shrink and crack. It will look more and more like the synthetic material that it is, a material that looks out of place on tile, a material which does not age.
Grout could be used to fill the crack. After all, grout is the concrete product that is used to grout gaps between tiles in the first place. However, thinset mortar is a better choice because it is harder and tougher and more adhering than grout,, and it can tolerate slight displacement (movement) while grout cannot. In fact, it would have been best if the entire mosaic had been “grouted” with thinset. I suspect that heating and cooling the oven in cycles over time may cause other cracks to appear or reappear, and these should have thinset rubbed into them as needed. Hopefully any new cracks or reappearing cracks will be smaller, but in any case, thinset is better equipped to withstand the stresses of expanding and contracting than grout.Mosaic crack being repaired with thinset mortar. The mortar is spread on and worked into the cracks and wiped off just like grout. Thinset is superior to grout because it is harder and tougher and can tolerate slight movement. Aesthetics and Authenticity
Think of high-end restaurants in reclaimed urban warehouse spaces: the exposed beams, the plaster chipped away in places to reveal the stone walls underneath, the different architectural elements like fire doors and hoists deliberately left in place to call attention to the space’s past industrial use.
To me, one of the more interesting things you can see in the mosaics of Mexico and the Mediterranean basin are the repairs that have been made to these over the years following earthquakes and other damage. I’m not thinking of the repairs that were made in modern times by archaeologists or professional conservators sparing no expense to make the mosaic look as if the damage had never occurred. I’m thinking of repairs made in the distant past by inexpert hands or by people with limited access to materials. I’m thinking of repairs like mortar-filled voids and replacement tiles of not-quite-the-right color and how you can sometimes see a series of these inexact repairs apparently made at different times in response to different injuries. To me, these inexact repairs more than anything else give me a sense of how ancient the mosaics are and how much history they have witnessed, endured even: earthquakes, fires, wars with slings and arrows, wars with bullets and bombs.
A large part of the ethos of mosaic art is it being an enduring relic of the past. If I were wanting to design a mosaic to look like an old relic, I might consider deliberately including mortar-filled voids and cracks to simulate past damage or maybe re-mosaicing some of these regions with coarser tile. With that in mind, is a crack appearing in a new mosaic in an Italian or Mexican restaurant a problem or a windfall? I’m thinking not. I’m thinking of the kid who deliberately scuffs up his new baseball glove so that it doesn’t look the unused glove of a rookie.
We now sell 24kt gold mosaic glass, and it really is gold and not the brass alloy imitation products that some competitors are rather shamefully selling as gold. We also sell the imitation gold brass foil glass. but we have it correctly labeled and appropriately priced.
The real 24 kt gold glass is molded tiles and have the bevels on the sides like vitreous glass tile, while the imitation brass foil tiles are hand cut and have flat sides. The real gold mosaic is superior to most of what I see on the market because the our gold leaf is fused into the FACES of the glass instead of being laminated on the bottom of a piece of glass. Our gold is inside the glass, but is close to the top surface and makes the tiles look AMAZING!Mini 3/8-Inch Gold Mosaic
We also have these in the 3/8-inch MINI size. They look like little jewels, maybe earrings missing their studs!Gold Mosaic Glass 10mm Wavy is real 24 kt gold fused into the surface of the glass. Smooth Gold Mosaic Available Too Gold Mosaic Glass 20mm Smooth is real 24 kt gold fused into the surface of the glass. An Economical Alternative
We carry the Imitation Gold Mosaic Glass at competitive prices, but unlike some of our competitors, we sell them as what the really are and do not try to pass them off as counterfeits. They are a great material in their own right.Imitation Gold Mosaic Glass 20mm Wavy is brass leaf fused under glass.
A competitor is selling crafts-grade tiles that are clear glass with a thin coat of color that scratches off. They have search engine ads that have “Mosaic art supply” in the title of their ads! That is why you think you bought the tiles from us, but they are not MosaicArtSupply.com, and this is not our product.
You can help stop this competitor from damaging my business name. READ TO THE END TO FIND OUT WHAT YOU CAN DO.
Earlier this year, a manufacturer sent use a set of samples that included colored and textured mirror tiles of various types like those you have been purchasing on competitor websites. We were very excited to get these, but testing revealed some disturbing problems.The reflective foil on the bottoms of the arts-n-crafts gems comes off when the tiles are cut. Foil Comes Off When Cut
We thought the textured-bottom mirror tiles were a clever product because they came in odd trapezoidal shapes so that the user could avoid cutting the tiles and breaking the coating on the reflective foil that protects the foil from being oxidized and tarnished by adhesives.
However, some people will want to cut the tile anyway no matter what is recommended, and so this problem with the foil delaminating and coming off the glass is a real issue,A More Serious Issue: Clear Glass
The problem with the foil pales in comparison with what else cutting revealed: The glass itself is clear, and the coloring is a surface treatment that is easily scratched by sand and grit!SERIOUS PROBLEM. Clear glass tile with color added as a thin layer on top is a serious problem for architectural and art use because the thin layer of color is easily scratched by sand and grit. Craft projects made from these will look cheaper and more artificial as they age, while those projects made from real colored glass look more authentic as they get scratches and chips. Color Scratches Off Sand and grit can scratch the color off the clear glass
The clear glass with a colored surface was not the only serious problem we found. Some of the manufacturer’s other types of mirror tile had a much thinner type of protective coating to keep the reflective metal from getting oxidized by the glue –more like the coating on generic mirror stock than tile.They Are Not MosaicArtSupply.com
A competitor is using the phrase “Mosaic art supply” in the title of their search engine ads, and that is why you think you ordered the mirror tiles from us. We only sell materials that are architectural and fine art quality.Screen shot of Google showing competitor’s use of “Mosaic art supply” as the title of their ad. Always verify the URL of any website you browse. That is a basic safety practice for using the Internet!
I have contacted Google explaining why I think the competitor’s use of “Mosaic art supply” as the title of their ad is a deliberate attempt to create confusion between websites:
“Mosaic art supply” is not a valuable keyword phrase for an ad based on the number of searches. Based on search frequency compared to other mosaic phrases, this keyword phase would sell for well under half a dollar per click. but currently costs several dollars and rising. The ad rate would not be worth paying if not for our use of the phrase as our domain name. Any Internet retailer can tell you that many people do not pay attention to the URL and that ad titles are often equated with business name.What You Can Do
Mosaic Art Supply is a small LLC that exists to provide resume-building day jobs for emerging artists, who would otherwise be waiting tables or answering phones in more stressful environments.
We don’t have the budget to respond to questionable ad campaigns by a competitor who supplies craft-grade materials to discount stores. What we do have is some standing in the mosaic community.
What we are asking from you and others is that you create links to favorite products and instructions on our website from any appropriate venue (Facebook, your blog, your website, social networking sites, forums, etc.). Linking to some of our more useful blog articles would also help.
With sincere thanks,
Joe Moorman, owner Mosaic Art Supply
Artist and MAS employee Natalija Moss has recently completed a series of mosaics made from stained glass, and they are definitely worth seeing and discussing for several reasons. Natalija’s other artwork and video game plugins can be seen at her Lady Natalya website.“Erza” Stained Glass Mosaic by artist and MAS employee Natalija Moss. Note how the dark charcoal-colored grout line mimics the lead channel soldered joints of stained glass artwork. This piece is technically a mosaic (it is grouted “tile” on an opaque background), but it is aesthetically stained glass in terms of the sizes of the individual pieces of glass and how they are used to render details.
Stained glass can be used in mosaic artwork in two different ways. The stained glass can be cut up into small tesserae (pieces) just like glass mosaic tile in a typical mosaic approach, or it can be used in larger pieces similar to how it is used in stained glass artwork. This latter approach preserves the large swirls of color which cutting into smaller pieces tends to break up, and this allows “the glass to do the work” as stained glass artists often say as a maxim. What they mean by that expression is allowing the swirls in the stained glass to create visual interest and suggest details such as ripples in water instead of rendering each ripple individually as a separate piece of glass.
I tend to think of mosaic artwork in terms of the traditional mosaic approach and cut any stained glass I use into tiny tiles, but I was impressed by how successful Natalija’s mosaics were and how conspicuously different they were from my preconceptions.
Compare Natalija’s “Erza” mosaic to Doug and Carly’s “Van Gogh Self Portrait” mosaic. Notice how the flowing andamento so crucial to the the Van Gogh mosaic is COMPLETELY absent in Natalija’s work.“The Major” Stained Glass Mosaic Artwork by Natalija Moss. Note the complete absence of flowing andamento (arrangement of tile in concentric rows to suggest motion) which is normally so crucial to mosaic art
On reflection, I can see that Natalija’s use of stained glass in larger pieces instead of many small tesserae is merely stained glass artwork as stained glass artwork is typically done, but there are two reasons that Natalija’s work still stands out. First, she didn’t give up the stained glass convention of larger piece sizes merely because she was mounting on an opaque background to make a mosaic.
The second reason Natalija’s work caught my notice was the freshness of her themes/subjects. As a rule, stained glass artwork tends to use some of the most cliche designs to be found in art and crafts marketing (which is saying quite a bit), so Natalija’s use of subjects from Japanimation is fairly novel for that medium. I think that grabbed my attention as much as the absence of andamento.“Penguins” Stained Glass Mosaics by Natalija Moss demonstrate that it is possible to be cute without being saccharine sweet. Note how the background colors are warm and appealing instead of the cold blues that might be more naturally expected. To paraphrase the American painter James McNeill Whistler, “Nature must be corrected.” This is an important point to remember when designing compositions and when selecting colors. You can move a tree to the side to frame a scene. You can select a completely different background color quite easily when you aren’t attempting photographic realism. A Digression On The Failings of Stained Glass Retailers
It has been very easy for me to ignore stained glass artwork for the most part in the 13+ years I have been running Mosaic Art Supply because so much of it I came across by chance was so cliche and dated. The butterflies, bald eagles and tulips you see so much of now in stained glass catalogs appear to be the exact same patterns I saw 15 years ago and as a boy in the 1970’s.
I think the people who sell stained glass have done a disservice to their customers and to their own wallets by promoting their industry in such a tired way. Sure, there will always be people who want sappy stuff because they like sappy stuff or think it is easier to make, but I think that sort of approach tends to kill interest in the medium over time by not attracting younger people and people with more serious interests in art. This converging on the cliche by stained glass marketers has also meant that their patterns were more easily mass produced by countless Chinese competitors, which further destroys profit margins as everyone “races to the bottom” to compete solely on lowest price.
All of my product decisions at Mosaic Art Supply were made with one eye toward avoiding these traps, and this is why we have always avoided selling the mosaic craft kits we see on the market. I want to promote a serious interest in Art with a capital A because I think it is in the best interest of my industry, and because if I wanted to help distribute mass-produced junk, I could have stayed in the corporate world. In the sense of being something a person creates for deeply personal reasons, Art is one of the few intrinsically sacred things in a world where everything is increasingly profaned and commercialized. That is why the prevalence of cliche stained glass patterns has always struck me as being nothing less than a tragedy, a huge opportunity lost. Even if you prefer those particular subjects/themes, it should still strike you as conspicuously strange that you don’t often see alternatives to those themes being offered as patterns by stained glass retailers.
Here is an anecdotal case study of how craft kits get it wrong and actually detract from the art experience:
This past Halloween, my ex wife hosted her annual pumpkin carving party for our five-year-old son and all his friends, and I helped as usual.
The party was the same format as previous years, but my ex-wife bought some pumpkin carving kits that were so flawed in both concept and execution that I find myself still thinking about them. In fact, the kits seem to epitomize what is wrong with most craft kits and craft products in general.
Traditional pumpkin carving is a great opportunity for ordinary people to work with their hands and make some art, and for many people it is probably be the only visual art they make the entire year. No special equipment is needed, and a person gets to make their own design. In my opinion, this is what makes pumpkin carving an important form of art, and I mean art in the highest sense of the word, Art with a capital A. Traditional pumpkin carving is also a great practical exercise in how to render personality and emotion with a few basic lines and shapes.
Contrast this with the pumpkin carving kits:
In order to appeal to the person buying the kits, the kits contained patterns for elaborate designs, designs that were impressive mostly because they were so elaborate, designs that ensured that most people using them would be totally focused on getting these professional results instead of self expression. The kit’s packaging featured pictures of pumpkins decorated with these over-the-top designs because that was their main purpose: to sell the kits.
Clearly these pumpkins had been carved by someone with an advanced experience level, and in all probability the professional artist who carved them needed several hours to do so, and probably needed more than a few practice pumpkins. From my own experience in art and manufacturing, I strongly suspect that several practice pumpkins were abandoned almost immediately due to early cuts that didn’t go as planned.
The pumpkin designs on the kit’s packaging included fine details that most people could not even sit down and draw much less carve. In fact, some of the designs were so filigree that you would have had to keep your pencil sharpened continuously just to be able to draw them. Think a lacy spiderweb spelling out “Happy Halloween” in the strands of the web. Some of the other designs were naturalistic renderings that required complex shapes be duplicated exactly for the image to look right. Think a light-and-shadow rendering of Boris Karloff’s face as Frankenstein.
So how did my ex-wife’s pumpkin carving party go? Exactly as I thought it would: Instead of getting to make their own designs and experience art, the children quickly became frustrated and annoyed and then required the help of all their parents, who also became frustrated and annoyed in varying degrees over time. Unlike previous years’ pumpkin carving parties, people could barely socialize because they had to do a task as intricate as threading a needle, and do it in fading outdoor light with impatient children looking on.
Of course, I tried to explain all this beforehand to my ex-wife, but like most husbands and ex-husbands, it doesn’t matter how many degrees or accomplishments we have. When we speak with our humble wives, we are all village idiots that don’t know anything. My two engineering degrees, a childhood spent in the mechanical and building trades, a lifetime of making art, a 13+ year stint running my own art supply business with all that entails in terms of consulting on school art projects and studying market trends, all of that was completely irrelevant.
At least it was until the party began…
I brought three pumpkins to the party. I didn’t even think about designs beforehand, I just made sure that what I carved used simple bold lines and no more detail than eyes and a mouth and maybe a nose. All of the expression was in the size and shape and spacing of these fundamental elements, yet each of my pumpkins distinctly conveyed the different emotion for which they could have been named: Scary, Scared and Silly.
Needless to say, I had finished all three of my pumpkins well before anyone else had made much if any progress at all on their pumpkin. I placed my pumpkins in a row near the edge of the snack table, and arranged them so that Silly appeared to be laughing at Scared, who appeared to be startled by Scary. Then I went around the patio and tried to help the demoralized children and the increasingly frustrated adults, some of whom were struggling not to cuss in front of the 5 and 6 year old children.
Meanwhile my ex-wife walked out with a tray of drinks and saw my pumpkins arranged in a row and said, “These are great! They look so good together like that. I told you the kits would be a good idea.”
Of course, she didn’t have to spend too many minutes out with the other parents on the patio before they had helped her revise her opinion of the kits, and that was before the cheap plastic handles started breaking on the cheap cutting tools. After that started happening, I think there was at least one or two parents who would have gladly lynched the creators of the pumpkin carving kits.
Yes, part of the problem was the fact that my ex-wife rather mindlessly selected a kit geared toward advanced designs and used it in an inappropriate social setting, but that only aggravated problems that already existed with the kits: The kits were about producing over-the-top results instead of experiencing a traditional art form in the way it had been experienced for generations. But even that statement does not adequately explain what was wrong. The kits were about PROMISING over-the-top results, but they were pretty weak in the delivery.
What disturbs me most about pumpkin carving kits is that all of its flaws seem to represent fairly prevalent trends in craft kits as a whole:A strong emphasis on packaging and presentation. Cheaply made tools and materials, sometimes so poorly made that they probably cost the manufacturer less than the packaging and presentation elements. An emphasis on professional-looking results instead of an emphasis on the design process or the art experience or what could be learned in doing the project. Encourage users to copy expertly made prototypes instead of making their own designs. Kits more designed to be sold than used. A complete disregard for what negative impacts the kit might have on traditional crafts, art education, the art experience, etc. Use of designs that are cutesy or calculated to appeal to the overly competitive host. Think of pumpkins carved with words to show off what a clever homemaker you are instead of jack-o-lantern faces.
One way the pumpkin carving kits differ from what I’ve seen in other craft kits is that these other craft kits increasing try to make things easy or foolproof by eliminating most of the actual work. As if eliminating the design process weren’t enough, many kits try to eliminate the potential for failure by eliminating most of the activity of making the project. Instead of having the user do the different manufacturing processes, these type kits usually have things pre-painted or pre-wired or pre-whatevered, and all the end user does is snap things together. In fact, there are craft kits you can buy where I suppose unwrapping the kit and checking the materials would take more time than assembling the kit.
I guess that is nice if your goal was merely to possess the end product, but not very nice if you actually wanted to learn very much about woodworking or weaving or whatever type of craft it was supposed to be about. At least I can say that for the pumpkin kits my ex-wife picked out: they left you plenty of work to do, and you were free to fail from the get go.
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 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. Have children spend one or two sessions arranging tile into designs on these squares/trays. Have teachers or parent volunteers mix up and spread thinset on the stepping stones. 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. After the thinset has hardened for a day, grout the mosaics with more thinset or grout. 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. MORE COMPLICATED DESIGNS?
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.
We regularly see questionable information online concerning how to mosaic and how to do other art and craft projects. Mostly this information is questionable because it was written without regard to durability or how the project could have been used as an opportunity to make real art (personal, unique) instead of making clones of something already mass produced. Sometimes we even see instructions that are potentially dangerous or even likely to be dangerous. The recent fad of tiling floors with copper pennies may be an example of this, at least in certain situations.
In micro amounts, copper is a nutrient and is found in all plant and animal life. On the other hand, excessive exposure to copper can be toxic, particularly if a person has a genetic predisposition to a condition called Wilson’s Disease, in which the liver is unable to remove excess copper from the body.
Sure we all handle copper pennies every day, but this is different from lining a living space with them, especially on a floor where foot traffic will abrade the pennies and household cleaners will accelerate the forming of copper oxides and other toxic compounds.
Different websites mention coating the pennies with urethanes and other sealers prior to use. That is probably good in theory, but I’m not confident that the thin layer of sealant will isolate the copper for very long under normal use conditions. Keep in mind that copper is fairly soft and fairly reactive. What is acceptable for a wall or a mosaic sculpture is often inadequate for a floor.
Terracotta flower pots are highly susceptible to freeze damage because the material is extremely porous. Moisture seeps into the tiny pores, freezes and expands, and then the surface flakes off as shown below. However, it is possible to use terracotta as a mosaic base provided the mosaic is mounted correctly and the artist understands the limitations of the material.Terracotta flower pots are highly vulnerable to freeze damage because they are soft and porous. The damage could have been minimized by sealing the pot inside and out with a tile and grout sealer. Minimizing Damage To Terracotta Flower Pots
Freeze damage can be minimized by sealing the flower pot inside and out with a tile and grout sealer from a local building material store. Tile and grout sealers are silicone products that plug tiny pores and prevent moisture penetration. They can also interfere with bonding, so we recommend sealing the flower pot AFTER your mosaic is complete. Note that even if you do seal a terracotta pot very well with multiple applications of sealant, it still won’t last as long as a concrete pot would.Concrete Pots Are Preferred
A terracotta pot might be an acceptable base for an abstract mosaic quickly made from random colorful tile, but detailed mosaic designs take more time and effort than that, and they deserve a more durable base. Concrete flower pots and planters are available at most lawn and garden centers, and whatever extra cost is well worth it. A single winter of hard freezes can totally destroy a terracotta flower pot left outdoors. Also terracotta is also easily broken and cracked during normal use.
Sure you might already have terracotta pots at home that you could use for free, but how much money are you saving if the mosaic doesn’t last six months? Once you take the time to mix up mortar and attach the tile, you’ll be glad you took the time to find a concrete base, even if your design is just random tile.Use Mortar Not Glue
The tiles should be attached with thinset mortar instead of glue. White PVA adhesives such as the Weldbond we sell are water resistant when fully cured, but there is a difference between water resistant and water proof. Flower pots are containers full of damp soil, and that means the back of the mosaic will be continually subjected to moisture and acids from decaying organic matter. The acidity of the leach water means that flower pots may be a more extreme environment for mosaics than pools and fountains.
Thinset mortar can also be used to grout your mosaic. Both grout and thinset are powdered portland cement products, but the thinset is stronger and more adhesive. If you are going to have to purchase a powdered cement product to make the mosaic, get the better product (thinset), and use it for everything. You can even reinforce the inside of a terracotta flower pot by plastering it with thinset.
Mosaic stepping stones are great first projects, but they don’t have to be cheap and cheesy or dangerous. Keep in mind that if you totally cover the surface of the stone with large pieces of stained glass, it is likely to be slippery when wet. If you leave sharp edges of glass exposed, or allow the grout to erode out from between the glass over time, then your stepping stone is less of a stepping stone and more of a device for cutting bare feet. Both of these problems can be avoided by following best practices and using sound methods.A Brief Rant
First, avoid the craft kits that have you make a butterfly or some other canned 1970s design by gluing large pieces of pre-cut stained glass onto a stepping stone. Glue will not resist moisture over time, and these kits are the poster child of slippery when wet. They also look exactly like all the other mass-produced stepping stones from China and thus have all the charm of a fast-food wrapper or billboard.
Instead, make something original by pressing your own designs of small tile into wet concrete, and be confident that whatever skill you lack may actually add to the originality and charm of what you make. A homemade stepping stone is supposed to look like a homemade stepping stone and not something made in a Chinese prison factory based on a design first copied in the 1970s.Glass Tile Is Best
Glass tile doesn’t have any pores, and so water can’t penetrate into it and freeze and crack it. Ceramic materials have lots of pores, and there are tiny cracks in the glazing, so these materials are more susceptible to freeze damage. However, porcelain and dinnerware and other high-end ceramics are a lot more resistant to freeze damage than something like glazed bathroom tile, so they can be used with discretion. Remember, the more soft or crumbly a ceramic material is, the more susceptible it is to freeze damage. Avoid terracotta, glazed ceramic bathroom tile and anything that easily breaks.Decide Which Method To Use
There are two main methods of making a mosaic stepping stone. It is better to use a mold if you are wanting to use marbles or large stones or other found objects not easily attached to a flat surface.1. Prefabricated Stepping Stones.
You can cement tile to a plain prefabricated concrete stepping stone purchased from a lawn and garden center.2. Stepping Stone Molds.
You can press tile into wet concrete in a stepping stone mold or have a mosaic design on contact paper at the bottom of a stepping stone mold and pour concrete on top of that.
Note that both methods require that you mix up a powdered concrete product because you cannot use glue to attach tile to an outdoor or wet mosaic. Instead, you have to use thinset mortar, which is a powdered portland cement with polymers added for enhanced adhesive properties and strength.Prefabricated Stepping Stones
Plain concrete stepping stones can be purchased from lawn and garden centers. These make great bases for mosaic stepping stones even if you are wanting to press tile into wet concrete instead of cementing the tile to a rigid surface and then grouting later. How is this possible? Easy. You simply spread the mortar on a little thicker than normal, say about 3/8 inch thick, and press the tile into that.Stepping Stone Molds
Stepping stone molds can be purchased or improvised from ordinary containers such as plastic dish pans and old metal cake pans from the thrift store. Various websites recommend using the nonstick baking pans from your kitchen and even make the claim that you won’t scratch them up, but I wouldn’t go that route. As a general rule, I avoid using anything from my kitchen in my art studio and then returning it to the kitchen, and I’m fairly sure that some people would manage to scratch the pan when they removed the hardened concrete stone. Besides, you can always get old cake pans from the thrift store or use a plastic dish pan or take an old plastic 5-gallon bucket and cut it down with a jigsaw. There is no reason to raid the kitchen when all these other options are available.
Tip: No matter which type of mold you use, make sure you coat it with non-stick cooking spray or petroleum jelly (Vaseline) to ensure that the hardened concrete stone can be removed easily.Sources of Improvised Molds:A stepping stone mold with some accessories. The pea gravel can be mixed with the thinset mortar to give it strength and bulk. Sources of Improvised Molds: plastic dish pans plastic totes purchased stepping stone molds old cake pans from thrift stores 5-gallon plastic buckets cut down with jigsaw plastic litter boxes (new or bleached) plastic plant trays cardboard boxes lined with plastic trash bags your spouse’s nonstick baking pans (not recommended) Two Ways To Use A Stepping Stone Mold
There are two ways to use a stepping stone mold. You need to decide which you will use, and the second is better for marbles and other found objects that aren’t flat like ordinary tile:1. Put the tile at the bottom of the mold and pour concrete over that.
You can place your tile UPSIDE DOWN in the bottom of the mold and pour the concrete on top of that. The easiest way to keep your tile from moving around when the concrete is poured on top is to put contact paper at the bottom of the mold with the sticky side up. Then you stick your tile UPSIDE DOWN onto the contact paper. This method is recommended if you want a very detailed design because it allows you to get all your tile carefully positioned before you mix up the concrete, which only has a few hours of working life before it starts to harden. Even if your design isn’t very complicated, I wouldn’t attempt it without the use of contact paper. Make sure you add the concrete slowly and gently tap the mold as you go along to make air bubbles come to the surface.2. Press tile into wet concrete at the top of the mold.
This method is best for mixed-media designs made from marbles and other rounded found objects that couldn’t stick reliably to a piece of contact paper. You simply press the objects into the concrete, and you have the advantage of being able to vary how far they are embedded and to see how the work looks as you go along.
Tip: Wait 30 to 45 minutes before you start pressing objects into the wet concrete. This allows the concrete to firm up a little so that your objects don’t sink to far into it.Using Thinset Mortar Instead of Ordinary Concrete
Thinset mortar mixed with a little pea gravel is MUCH stronger than ordinary concrete.
Most stepping stone instructions say to use ordinary concrete and often have tips about how to pick or sieve the larger pieces of gravel out of the concrete so that they don’t interfere with the tile or objects you want to embed in the concrete. One of the most significant hazards of doing mosaic work is breathing concrete dust, so if you were going to do this sieving or picking, you would want to do it AFTER you had mixed the concrete up, and that seems like a lot of pointless and difficult work to me.
Instead, I buy thinset mortar, which does not contain gravel, and I mix in small pea gravel in a ratio of 2 parts wet thinset to 1 part pea gravel by weight. For example, to make two small stepping stones, I recently used 8 pounds of wet thinset mixed with 4 pounds of pea gravel.
The pea gravel is needed because thinset mortar slightly contracts as it cures (due to the adhesive polymers), and all traditional portland cement products need and aggregate such as gravel or pea gravel to provide tensile strength.
IMPORTANT TIP: Set some of your thinset aside and don’t mix any pea gravel into it. Use this gravel-free thinset for the layer where your tile will be embedded so that no gravel interferes with the tile as you press it in. First, fill your mold about 3/8 inch from the top with the thinset mixed with pea gravel. Then fill the rest of the way up with the plain thinset. That top layer is where you would press the tile without having to worry about pea gravel in the way. If you have a pattern on contact paper at the bottom of the mold, you would first pour in some plain thinset and then top the mold off with the mixture of thinset and pea gravel.Tips for Using Thinset Mortar
I have written some instructions for using thinset mortar and some tips for keeping your hands and tools clean while working with thinset mortar.
My instructions in those two links are for doing very detailed work with thinset. Most mosaic projects (such as stepping stones) are a lot more simple. Most of what you really need to know about thinset can be summarized here:Wear a dust mask when mixing up thinset to avoid breathing dust, and mix it up outdoors for easy clean up. For Versabond brand thinset, we mix 1/4 pound of water per 1 pound of thinset. The package will have manufacturer instructions for how much water to mix in. You have about 2 to 3 hours of working time provided you keep the thinset covered when not in use. If you are working in conditions of extremely dry air, such as when the heater or AC is running), then use a humidifier to keep the air moist. Do not dispose of thinset in plumbing or drains. It is concrete and can harden underwater. Cleaning and Sealing
No matter which method you use, you should wait at least 24 hours before removing your stepping stone from the mold.
Sometimes stepping stones made on contact paper at the bottom of a mold will be removed from the mold, and the artist will discover voids between the tiles due to bubbles. Other times, you will see that concrete has gotten between the tile and the contact paper, and so there is concrete on top of the tiles. Both of these problems are easily fixed.
Voids are filled by mixing up small amounts of concrete and dabbing them in. Concrete on top of tiles can be scraped off using a small screwdriver or other steel tool. Use a spray bottle to mist the stone as you work to control any dust.
A few days after your stepping stone has hardened, you should seal it with a tile and grout sealer from a building material store.