To correctly choose an adhesive for your mosaic, you will first need to know which materials you will be using for both the substrate (backing) and tesserae (mosaic tiles) as well as the intended use and location of the mosaic. Failure to choose an appropriate adhesive or not allowing it sufficient time to cure, may result in tiles falling off your completed mosaic.
Here is a quick adhesive reference guide to get you started. For best results, always follow instructions on the the label.
PVA – Polyvinyl Acetate (aka Craft or Wood Glue) – white glue, dries clear
- Suitable for use in Direct Method mosaics as tiles can be coated with glue prior to placement on substrate.
- Also suitable for Indirect Method mosaics when diluted 2:1
- Not suitable for load bearing, can be used on mosaics that lay flat or that will not be required to bear weight.
- Non-waterproof, therefore is not suitable for exterior applications.
- Diluted it can be used as a sealant for porous substrates such as terracotta and unglazed ceramic pots.
EVA – Ethylene Vinyl Acetate (sometimes labelled as Exterior Craft/Wood Glue)
- Water resistant but not water proof – do not use on mosaics that will be submerged in water.
- Can be used in outdoor locations that will get wet.
Epoxy Resin – two part adhesive
- Suitable for internal and external mosaics.
- Extremely strong adhesive.
- Produces a lot of fumes (use in well ventilated location).
- Suitable for outdoor mosaics which may be submerged in water.
- Can hold heavy tesserae (eg; stones, heavy tiles).
- Can be tricky to work with as they are extremely sticky, can be quite runny and usually set fairly fast.
- Not recommended for beginners to mosaics.
Weldbond – similar to PVA glues
- Recommended by many mosaic artists for internal mosaics.
- Can be used on cement, concrete, bricks, plaster, metal, glass, wood and tiles.
- Stronger than the average white craft glue.
- Water soluble, no fumes, non-toxic and easy to clean up.
- Dries clear making it suitable to use for glass on glass applications (see manufacturers instructions).
- Not waterproof making it not suitable for exterior applications.
- Suited to Direct Method of mosaics as tiles can be coated with glue prior to placement.
- Diluted it can be used as a sealant.
Cement Based Adhesives (polymer modified cement glue) – Thin-set is a cement based adhesive
- Recommended for exterior mosaics.
- Suited for the Indirect Method of mosaics for making an adhesive bedding. Works best for outdoor work, floors and heavy traffic areas.
- Best adhesive to use if using the Direct Method and uneven tesserae.
- Its flexibility and strength can be improved by adding an acrylic bonding additive.
- Great for stepping stones, birdbaths, terracotta and an exterior mosaics.
- The bond to both the teserae and the backer material is improved by adding an acrylic additive to the adhesive and priming the backer material, before applying the paste.
- Available from tiling specialists.
Mastic – pre-mixed adhesive that is either latex or petrochemical base
- Not as strong as cement based adhesives.
- Used to attach tile to drywall.
Clear Silicone – silicone
- Dries clear, so it is great for glass on glass projects.
- Also available in a variety that won’t damage the silvering on mirror (check label for suitability).