Mosaic Terms

Some of the more common terms relating to mosaics, that you may hear or see mentioned:

Andamento :                              the way tesserae are cut and placed, according to size, regularity of grout line, flow and in relation to each other.

Acrylic (Plexiglass) :              A clear sheeting, used as a substrate for glass mosaics in the garden, and suncatchers. Use 3mm for smaller pieces, and 4.5mm or thicker for large pieces.  Cut with a laser cutter. Merlin Mosaica stocks a wide range of acrylic shapes.

Breaker/Breaking Pliers :     Used to break scored glass sheets.

Cementitious Adhesive :         a.k.a Tilers Cement or Thinset (in the US). The adhesive used to adhere tesserae to an opaque substrate.  Not to be used on wood or metal. Typically comes as a dry powder that is mixed with water or a latex additive for extra strength.

Colour :                                           Made up of hues (red, blue, green, yellow etc), tones (varying values of the base colour), tints (base colour with white added), and shades (base colour with black added).

Ceramic nippers :                      There is a variety of types that are available for cutting ceramic tile: Compound, side-biters, parrot beak.

Ceramic (and glass) scissors :        Similar in action to household scissors, these are great for cutting ceramic and glass. Blades are not replacable. Merlin Mosaica sells these as part of the Seabell range of tools.

Course :                                           a row (line) of tesserae.

Crash Glass :                               Broken tempered (safety) glass. Crazes into small pieces rather than sharp shards. If handled gently, can stay in islands. Beware: Crash glass is very sharp.

Embellishment :                        Something added to your mosaic. Typically adhered over the top of your mosaic after grouting.

Epoxy:                                            A family of resinous materials. Typically come in a 2-part (sometimes 3-part) mix, one of which is a hardener. Once combined they start to cure, and eventually form an extremely durable material. All epoxies are sensitive to UV light, and the clear ones will change colour over time.
Found as adhesives and as grouts. In mosaics, the practice of pouring clear epoxy resin over your mosaic is best avoided, as it looks “plasticly” and can yellow over time. It also will scratch.
Merlin Mosaica sells Litokol Starlike EVO Epoxy Grout, including Translucent (Crystal) which is for use with glass only.

Field :                                            an area of tesserae that relates through colour or tone.

Fusions :                                       Tesserae or embellishments made from fused glass (glass that has been melted/fired in a kiln).

Glass-on-Glass (GOG) :         The practice of using clear glass as a substrate. Usually translucent or transparent glass is used. When grouted in black, can emulate the look of stained-glass windows. When worked on Acrylic, the more correct term is GOA.

Grinding :                                    Polishing the edge of tesserae to remove sharp points or refine a shape. Can use an electric glass grinder, a diamond file/grindstone, or a diamond hand pad. Always use water when grinding to minimise silica dust (VERY harmful).

Grout :                                           A compound applied to tesserae once adhered. It stops dirt and unifies the look of a mosaic. Some mosaics are NOT grouted (especially those made using Smalti). It is NOT an adhesive, although it does stabilise the work.

Grozing Plier :                           A tool used to nibble off sharp edges from a scored piece of glass

Hammer & Hardie :                A pair of tools used to break smalti, marble and other thick tesserae. The Hardie is traditionally mounted in a tall block of wood on the floor, but desktop versions are also available. Hammers come in different weights.

Inclusions :                                 A general term covering fusions and embellishments.

Interstices :                                The gaps between your tesserae. Often overlooked as a part of mosaics, but it can have a great deal of impact on your work. How wide? How uniform?

Mesh :                                           Alkaline resistant mesh is used to adhere tesserae to for transferring to their final location. Useful if building a mosaic to be installed on a vertical wall. Available in plain, sticky and heat sensitive.

Nipper  (wheeled):                 A tool that nips glass and other tesserae into small pieces.  Some (such as the Seabell Glass Wheeled Nippers) are for glass only. Others may be used for both glass and ceramic. However, Ceramic will blunt the wheels more quickly.

Opus :the style of andamento used in a mosaic.

Picassiette :                               Mosaics made from broken plates, and other tesserae. Often 3-dimensional.

Scorer :                                         A carbide-wheel or diamond tipped tool that makes a score-line on stained glass, so that it can be broken in a controlled manner using breaking and/or grozing pliers.

Smalti  :                                        A form of glass used in more traditional mosaics. Italian, Mexican, and Chinese forms are the most common.

Substrate :                                  what you are gluing onto: Examples are concrete, MDF, Glass, a 3D object, a tabletop. Can be made of many things.

Tesserae (Sing. Tessera) :the tile, or pieces that are adhered to the substrate. Can be ceramic, glass, metal, found items. Square, rectangular, circular, flat or 3 dimensional. The possibilities are as endless as your imagination.
                                                      NOTE: This is often abbrev. to Tess.

Thinset :                                       The American term for Cementitious Adhesive. Commonly used in Mosaic Facebook groups.