| Techniques of Community Mosaics
by Olivia Gude
Recently, Chicago Public Art Group artists inspired by folk art practices and a visit to Isaiah Zagar, a master of direct mosaics in Philadelphia, have been experimenting with loose, more freely drawn mosaic works combining various kinds of tiles and hand painted ceramic pieces. Working in this way, tiles are broken and placed into buckets. Tiles are not cut or carefully fit. Adhesive is applied to the tile as it is taken from the bucket and attached to the wall. Participants outline and fill large, simple areas. After covering areas with large tile pieces, small tile fragments are filled into gaps between tiles.
Chicago Public Art Group is referring to these as Bricolage Mosaics, using the French word that designates making something out of many disparate elements.
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Traditional Indirect Method
In this variation of the indirect method, used to create many of the classic Italian mosaics, pieces of smalti (small, thick chunks of glass) are cut with a chisel. A full-scale drawing on the table is covered with a sheet of clear plastic or glass. Laid on top of this is a fiber or plastic mesh. Individual tiles are glued to the mesh with cement, face side up. The piece is grouted while on the table and then carefully packed and transported to the installation site for affixing to the wall with cement. This method requires the use of carefully-fit thick glass tiles, set by highly trained mosaic workers and installers. It is not well suited for volunteer-based community mosaic projects.
In another variation of the indirect method, the piece is created upside down on the table. Draw the design full-scale and backwards—as seen in a mirror—on heavy paper. Nip pieces of tile to the desired shape and affix them finished surface down onto the paper with water-soluble glue. When the work is completed, cut the design into manageable pieces (about one foot square) and carefully label each section (A1, A2, A3, B1, B2, etc.). Cut shapes that will fit together like puzzle pieces.
Attach sections to wall with appropriate adhesive. Allow tiles to set in the adhesive for the designated length of time. When adhesive is dry, use sponges to dampen the paper with water. Remove the damp paper from the surface of the mosaic. Scrape out excess adhesive that is above the surface of the tiles. Work grout into cracks between tiles and wipe the surface clean.
These methods are called “indirect” because the tiles are first assembled off-site and are not adhered directly to the wall. An important advantage of this method is that the tile work is done at tables in the studio, thus allowing more control of the cutting and placement of tiles. Because one is placing the tiles on the paper upside down, this method is most suited for use with tiles that are colored all the way through such as glass or unglazed, colored porcelain.A disadvantage of all methods that make use of paste, glue, or cement when placing the tiles is the mess on tiles, hands, and tools when participants are shaping tiles and affixing them at the same time. An aesthetic problem when working “upside down” is that color and tile work choices are made while looking at the artwork backwards.
Draw the design full scale and face up on good quality paper. Some artists use a heavy weight paper; others prefer to use gridded or ungridded vellum. Cheap white roll paper is not suitable because it has a tendency to tear when tiles and tools are repeatedly placed on its surface. It also has a tendency to wrinkle and pucker when it absorbs even a small amount of moisture from hands resting on it. Paper must be taped tautly to the tabletop. Tape all edges because it is very disruptive of smooth mosaic making if little pieces get under the paper.
Nip pieces of tile to the desired shape. Lay the pieces onto the paper. Continue adding pieces. When necessary, shift tiles that are already laid to achieve a better design or a more accurate outline. After completing a section of tile work, very carefully cover the section with clear plastic adhesive film such as Protecto Film (for light weight glass tiles) or Can-Do Tape (for heavier ceramic tiles.) See the Resources chapter for sources. Once the plastic adhesive film has been lightly “dropped” into place, smooth the film gently and firmly onto the tile. Trim the film so that it is not sticking over the edge of the tile work onto unfinished areas.As you finish each new section, apply plastic film to the new work and overlap onto the finished work. When completed you’ll have a mosaic held together by many overlapping sheets of plastic film. Cut the finished mosaic into manageable pieces (about one foot square) and label each section (A1, A2, A3, B1, B2, etc.). Cut shapes that will fit together like puzzle pieces to ensure correct alignment.
Attach each section to wall with appropriate adhesive such as mastic or thinset. (See installation information below.) Allow tiles to set in the adhesive for the designated length of time. When the adhesive is set, gently pull the plastic film off the tiles. Occasionally, a tile may come loose with the plstic film. As you proceed, scrape out the dried adhesive and reaffix each loose tile with a bit of fresh cement or mastic. When all the plastic film is removed, examine the mosaic carefully, and scrape out excess cement or mastic that is above the surfaces of the tile. Work grout into cracks between tiles and wipe the surface clean.
There are many technical and, consequently, aesthetic advantages to working in the indirect method, particularly when making a community mosaic. As in traditional indirect methods, the tile work is done at tables in the studio, thus allowing more control of the cutting and placement of tiles. It is easier for the mosaic director/community artist to teach participants and monitor the quality and progress of the work. The mosaic is worked face up, therefore, participants do not need to try to visualize how the design will look when flipped over.
There is no mess with paste or cement at the tessellation table. Participants can concentrate on the shape of individual tiles. An important advantage of this method is that tiles can be repositioned as the participant gradually develops an area. The mosaic director can suggest or make needed changes before affixing the tiles with the clear plastic adhesive film.This indirect method allows many people to work on different segments of a mosaic simultaneously People of various physical abilities can work on the project. The completed artwork can be installed in interesting, dramatic, and difficult-to-reach locations by a small number of skilled professionals and volunteers.
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When you have decided on the final design make a crisp line drawing of the pasted together design. Use a copy machine to make a small version of the final drawing. Give these out to the participants and ask them to use colored pencils to explore possible color schemes. If you already know the color of your tiles, only give out colored pencils in those colors. Discuss color schemes. Be sure to experiment with reversing which areas are light and which are dark.
Unexpected value contrasts often create the most dramatic hue/value effects. Combine ideas from various color schemes.
Make a small transparency of the drawing. Use an overhead projector to project it at the correct full-scale onto large paper taped to the wall. Trace lightly.
Darken the lines on the full-scale mosaic drawing, refining, smoothing, and adjusting as you go. Use actual tiles to help determine the sizes of various parts of the design. For example, if there is a border around an area, try to make the border the width of 1 or 2 full tiles, rather than 1 3/4 tiles, requiring lots of cutting and a less crisp edge.
Make a pattern of the overall shape of the mosaic on thin paper. Cut this out and fit it to the actual site. Make size adjustments to the main drawing as necessary. This step, completed early in the project, can save lots of frustrating re-cutting and fitting later.
When making the actual mosaic, be open to changes and fresh ideas. Try to plan places in the design in which participants can experiment with unexpected details or unusual tessellation patterns.
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Use the best quality tile nippers you can find or afford. There are many styles of nippers. Experiment to find a nipper style that works well for you and for other project participants. In general, nippers with carbide tips are more expensive, remain sharp longer, and are more effective especially when cutting glass or porcelain. Nippers must have a spring or you will wear out your hand flipping open the nipper after each cut.
Even high quality nippers wear out after being used continuously for 1 or 2 months. It is not possible to sharpen carbide-tipped nippers yourself, but a high-grade machine shop might be able to do this for you. There are also brands of nippers in which the carbide tips can be replaced. Sadly, it is usually necessary to discard the nippers and purchase new ones.
Along with basic art supplies, other items that are useful to have in the mosaic studio are lots of sturdy tables, colanders for draining and washing tile (when it needs to be removed from backing sheets), scissors and snapknives to cut adhesive film, bandaids for the occasional pinprick cuts from tile fragments, wide masking tape to hold drawings to the table, plastic shoe boxes or dishpans to store tiles, shelves to store the boxes or dishpans, plastic plates with multiple sections to keep several colors of tile handy in a work area, tweezers to grab tiny tile pieces, clean 2 or 3” paint brushes to brush fragments off the mosaic table into a dustpan, and several brooms.
The angle of the snap is determined by the angle of the nippers on the tile. If you are trying to make a straight-cut, be sure that your nipper blades are perfectly in line with the edges of the tile. Many tiles have striations on the back—make use of these by holding the tile in such a way that the striations encourage the direction of snap you want. If you are trying to create an angled-cut, tilt the nipper blades in that direction.
Often the tile will snap in approximately the right way, but the edge will be jagged. Now you will use the technique of nibbling. Think of the nippers as teeth and gently gnaw or nibble away little bits of tile until you get a smooth line. Trying to take off too much material at once is likely to cause a snap that will fracture your desired shape and you will have to start nipping a new tile.
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The beauty of mosaics lies in the variety and inventiveness of the tile work. In good basic tessellation technique, tiles are carefully fit together so that the surface is mostly tile with little grout--it’s the tiles that are beautiful and colorful, the matte grout is only a framing accent.
Great mosaic work often uses different styles of patterning within the mosaic to create interesting formal contrasts or to reinforce the imagery of the work. Collect interesting tiles in various shapes. Study traditional and contemporary commercial and community mosaics to develop ideas for your personal tile style. (See the Mosaic Aesthetics: Tessellation and Composition chapter.)
When laying small glass tiles, plan a tessellation pattern related to the size of a single tile and work from one edge to another. Try to avoid ending with a tiny tile—it’s ugly and can be easily lost in setting and grouting. Sometimes one has to go back several tiles and intersperse several 3/4 size tiles to avoid ending with an awkward sliver.
Several years ago, I noticed that I was teaching two different kinds of skills at once in introductory mosaic training workshops. I was trying to teach people to decide what shape they needed to cut at the same time I was teaching them how to cut. The first results would often be lumpen, amorphous shapes—not only because the participant did not have the physical skill to cut the desired piece, but also because the participant did not yet have the perceptual and design skills to decide what pieces were needed.
Traditional mosaics are usually created with natural colored stone such as marble or granite or with colored glass smalti. Tesserae (tiles) are created by using a hammer and chisel to break the slabs of colored glass smalti into small chunks. Smalti comes in an almost infinite variety of colors, is quite expensive, and must be worked using traditional indirect methods.
Dare to limit your palette. Try not to be swept away by hue contrast. Mosaics that also incorporate dramatic value contrast tend to be more effective, especially at night.
Glass tiles (sometimes called Venetian glass) are usually small 20 x 20 mm (about 3/4 inch square.) and approximately 5/32” thick. They are relatively expensive ranging from $7.00 to more than $30 per square foot. Bisazza Mosaico is a popular brand with Chicago mosaicists. ttp://www.bisazzausa.com/ Because Bisazza requires orders to be made in full boxes, it can be prohibitively expensive for use in a small project.
Artists often use tiles from various sources in a single work because this gives them a broader range of subtle color choices. Label tile sheets or containers with the manufacturer, name or code, and year. Sometimes different color lots can give you added shading potential.
Art supply stores and art education vendors re-package and sell the same or similar tiles as described above with a high mark up. There are now on-line dealers who sell small quantities at what seem to be relatively decent prices. Mosaic Mercantile, a good source for small quantities, can also work out discounts for artists placing large orders. http://www.mosaicmercantile.com/
Purchase tiles at commercial tile stores. Try to find a “high end” store that carries many kinds of tile. Study the sample books. Identify tiles that fit your color needs and price range. Also, find tile outlet stores in your area. Visit them frequently. Stock up on unusual shapes or patterns. Become a tile collector.
Vitrification = Frostproof
Tile used in outdoor installations must be fully vitrified. This means that the material is fused into a hard, glasslike substance that does not absorb moisture. Glass tile does not absorb moisture and so it is suitable for exterior applications.
A Community Arts Mosaic Nightmare
My saddest community art memory is of arriving at a high school and seeing the messy, smeared remnants of mastic adhesive on the brick walls facing the outdoor stairway at the main entrance to the school. An inexperienced artist had tried installing tiles in frigid weather with an adhesive intended for indoor use. When the glue failed to set after several days and many tiles had been accidentally moved or knocked off the wall by passing students, some rowdy boys destroyed much of the rest of the mosaic deliberately. The principal ordered the rest of the tiles (still loose from unset mastic) be removed—leaving a gooey brick wall as the only testament to community strength and creativity.
Even if the mastic had been used in warmer weather and had set properly, the adhesive would have soon begun to deteriorate because of the effect of moisture and frigid temperatures. After a few years, the adhesive would have crumpled and the tiles would have begun to fall off the wall. However, even if the correct adhesive had been used, the tiles would have exploded during the first winter because they were porous ceramic tiles that could not withstand freeze/thaw cycles.
For this doomed project, the question wasn’t if the project would survive, it was how short would its lifespan be. This is a cautionary tale. Plan. Do your research. Consult tile professionals in your area. Don’t let a community arts disaster happen to your wonderful project.back to top
Technical Considerations for Installation
A mosaic can be a stunning, permanent addition to a school or community site symbolizing the strength, talents, and creative energy of the community. An improperly made mosaic can be a maintenance nightmare and communicates lack of skill and the inability of community members to positively shape their environment. There are even safety concerns because tiles are quite heavy so an improperly installed mosaic can literally fall off the wall and cause serious injury.
The simplest technical rule for making permanent mosaics: the structure which supports the mosaic, the preparation of the surface, and the tiles, adhesive, and grout should be of a quality approved for your particular situation by an experienced local tile setter.
Get to know tilesetters in your area. They can advise you on the technical requirements needed to create your mosaic. It matters if the support is metal, wood, concrete board, or plaster. It matters if the mosaic is installed under a continuously running fountain. It matters if the mosaic is outside. It matters if the mosaic is on the floor. An experienced tilesetter can help you with the basic information you need to make the correct material choices. Check with a few different people and see if the information jives. Older tilesetters have often been through rigorous apprenticeship programs in which they learned special skills for handling unique tile installations.
The installation for these is simpler and less demanding than outdoor mosaics. Almost any tile can be used on walls. Tiles used indoors are often softer and easier for students to shape. The mosaic support (usually a wall) must be firm and free of dirt or chipping paint. Often it is best to scratch through the paint so that at least some of the adhesive adheres to the underlying wall, especially if the wall has been painted with a glossy paint. (Students seem to love to attack walls with screwdrivers or snap knives so it is easy to get volunteers for this job.) Sometimes a special undertile primer is the best choice for wall preparation. Mastic or other suitable indoor tile adhesives can be used. Depending on the look you want to create, almost any grout will be suitable.
The basic method of setting tile is to evenly spread adhesive on a portion of the surface with the unnotched edge of a trowel. Then use the notched edge of the trowel to “comb” through the adhesive, creating ridges of uniform height. The depth of the notches in your trowel is determined by the thickness of your tile. Use a tool called a “floater” to securely press the tiles into the adhesive.
The goal is to have enough adhesive to attach the tile without excess glue swishing up between the tiles at the level of or above the level of the tile depth.
Handmade pieces should be “back-buttered.” This means to spread adhesive on each tile as well as on the surface.
If you are creating a floor mosaic, check to be sure that the tiles are suitable for floor installation. In areas where the floor may become damp, it’s important to use unglazed tile to avoid dangerous, slippery situations. For floors, we recommend using unglazed colored porcelain; with this tile, you won’t lose color if the surface begins to wear away or chip. Remember that pools, showers, and fountains must be set with cement.
Outdoor Mosaic Installations
Outdoor mosaics must be made of frost-free tile unless you live in a climate that never freezes. In this case “never” literally means never and not almost never. Your area may get a frost only once every 20 years. What a shame if a frost in 2019 destroys an otherwise still perfect mosaic the community created in 2004!
Most mosaics that are outside are adhered with “thinset cement.” The grout should also be rated for outdoor use. Sometimes outdoor mosaics are set directly on a concrete or brick wall.
When setting over a rough wall, it is often desirable to adhere wire mesh to the wall with masonry nails and to float a smooth bed of cement over the surface. When the cement bed has dried and cured, the tiles are installed with thinset cement. This is a job for a skilled professional.
In situations where you cannot adhere the tile directly to the wall, divide the mosaic design into shaped sections. Try to create sections along lines that will disappear into the mosaic design, rather than chopping the mosaic up into squares. Cut plywood (concrete board or MDF for outside) into panels for these shapes. Remember to consider issues of size and weight when planning your panels. Install the tiles on the individual panels. Leave out individual tiles where you will need to bolt the mosaic to the wall. In these spots, use a bolting system that is appropriate to the underlying wall to attach the panels. Adhere tiles over the spots left empty for the bolts. (It’s a good idea to keep a bolt map in case the pieces ever need to be de-installed.) Grout the finished mosaic. Finish the edges with tile. On outdoor mosaics, it will also be necessary to seal the edges between the wall and the panels with a silicone caulking.
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Grout is a powder composed of sand and cement that is mixed with liquid to form a creamy paste. Grout fills in the spaces between the tiles and finishes the installation. See the chapter on Tessellation & Composition for a discussion of the aesthetics of groutlines.
When choosing grout, be sure that you have the appropriate mix for indoor or outdoor applications and for the width of your grout lines. Wide grout lines require a stiffer mix.
Color is an individual aesthetic choice. In standard commercial and home tile installations, the grout color and tile color are closely matched in order to create an even field. In art mosaics, it is often desirable to choose unusual colors and vivid contrasts. Many mosaicists love the look of dark gray or black grout setting off the vibrancy of the tile colors.
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Expand Your Knowledge
Doing mosaics is complicated aesthetic and technical business. We’ve been doing community mosaics in Chicago for over twenty years and we still spend quite a bit of time talking about technical and organizing issues. Have you found a new nipper you like? What caused a few tiles to pop off at such and such a location? Have you seen the latest (colors, sizes, shapes, textures) of such and such tile? How can we get all these folks trained to contribute to this mosaic? What would be the best installation technique in this situation?
Getting to know local professional tile setters and relying on them for technical advise is sound practice. Home repair books and books designed to educate tile setting experts are also good sources of information. Meeting other mosaic artists and sharing information is an important way to stimulate new design ideas and evolve technical knowledge.
Best luck in your tessellating.