Basic Mosaic Instructions
This is a brief, general overview of the mosaic process. We recommend the books, Beginners Guide to Mosaics, by Alison Hepburn & The Encyclopedia of Mosaic Techniques, by Emma Biggs, or taking a class at the Vinery for a more complete understanding of the art. We recommend that you wear safety glasses while making your mosaic and use a mask to avoid dust from thin set mortar and grout.
1. Surface Preparation: Your base surface must be clean and free of dust. Painted or varnished surfaces should be scraped with sand paper or a utility knife in order for the adhesive to stick. Wonder board or cement board is recommended for large projects, or exterior applications, as it is less likely than plywood to warp or be affected by moisture. When using thin set mortar, wet the base surface to keep the moisture in the mortar from being prematurely soaked out.
2. Creating the Tesserae: A mosaic is made of many small pieces of glass or tile, called tesserae. We like to use a mosaic nipper to break and shape glass into small, mosaic-size pieces. The nipper is a tool that is shaped like pliers with two small wheels that pinch the glass, causing it to break. We are always happy to demonstrate tools, and give you tips on using them. Be sure to wear safety glasses!
3. Attaching the Tesserae: We generally use exterior grade thin set mortar for any projects that will be outdoors, may be in contact with moisture, or are made of cement. Weldbond is a white glue that we like for gluing glass onto glass, such as when making a mosaic garden stake. It dries relatively clear (you must glue small pieces, rather than large for it to dry clear), and allows light to pass through your project. Tile adhesive may be used for projects that will be indoors and away from moisture. It works well for attaching tesserae to a dimensional or vertical surface because it is very sticky. It is also nice to use because it is ready for use right out of the can, no mixing mortar powder. Getting just the right amount of adhesive may take a test or two. It is important that your adhesive does not stand higher than your glass pieces, because it could protrude through the grout on your finished project. It is also important that there is a thick enough bed of adhesive to come at least half way up the sides of your glass pieces so that they are sufficiently held in place.
4. Grouting: After your adhesive has dried (24-48 hours), it is time to fill the spaces of your mosaic with grout. Put the desired amount of grout in a bucket and mix in small amounts of water until the grout is a thick paste. Do not make the grout too thin, as the excess moisture can cause your mosaic pieces to come off. Use a damp sponge or your gloved hands to spread the grout over your project and into all of the cracks. Do an initial wipe to get the majority of the excess grout off of your project. Allow the grout to dry for10 minutes. Use a well rung-out sponge to clean the project a bit more. After another 30 minutes, polish any remaining grout off of your glass. Note: Grout will discolor matte/sandblasted surfaces, wood and concrete, so protect areas that you do not want grouted with contact paper or masking tape! Also, we recommend that you cover any large pieces of mirror with contact paper until the grouting process has been completed, since it may scratch.
5. Sealing: Sealing is necessary if water or other elements will be in contact with your mosaic. Let your grouted mosaic set for at least 48 hours (Concrete projects - such as a patio stone made with Diamond Crete - must cure for 28 days prior to sealing ). Brush or sponge Armorcrete Sealant onto all areas of your dried project. Let the sealant dry 30 minutes and apply a second coat if desired. We recommend that you annually seal pieces that are kept outdoors, and bring your mosaics inside during the winter.
The Vinery staff is available for general questions about glass art, and we love to see the projects that you create. We offer mosaics classes throughout the year, and also give private lessons. Happy creating!
Disclaimer: No warranty is implied by these instructions. Please wear goggles when cutting mosaic materials or mixing grout. We recommend a dust mask when preparing thin set mortar or grout. Mosaic materials are often sharp. Keep out of reach of children. Do not dispose of grouting material in your household plumbing. Please link to these instructions freely, but email us if you would like to reproduce them.