Here’s a starter list of materials that you’ll need for creating exterior mosaics.
Materials (tesserae) for mosaic
Vitreous glass mosaics: Wide range of colours available. Flat surface. Suitable for outdoor projects.
Glass: Stained glass comes in a range of colours. Can be used outdoors. Choose backing and adhesives with care, as may be visible through glass (using white powder adhesive will let the light shine through the glass). You can also get glass beads and gems, and other lovely embellishments like millefiori.
Shells / sea glass: Frost-hardy. You can set them into a bed of adhesive and cover them with masking tape if grouting to avoid staining.
Crockery: May be damaged by frost unless it’s not porous. To test its suitability for exterior use, put a spoon of water on the top of the surface – if it’s still there after a few hours, it’s not porous and is suitable for outdoors. If it’s absorbed, don’t use it outdoors. Fine bone china is ideal for exterior use and often has lovely patterns / flowers.
Substrates / backing materials
- Slate
- Cement foam board – I use 6mm cut up into the shape I require using a jigsaw. I protect the edges of the board using tile adhesive mixed with Mapei Latex Plus Admixture (50/50 water admixture). Then I attach fixings. Here are the fixings I use for 6mm cement board as shown in the video:
- Button Fix – there are different types you can get – I like the triangular and rectangular shaped ones with two holes – types 1 or 3 it seems (but the numbers seem to be interchangeable when you Google them!)
- M5 T Nuts (5mm AN90 on Amazon)
- M5 countersunk bolts (16mm and also available on Amazon)
- Check out my video guide to cutting and preparing cement foam boards for use with exterior (and interior) mosaics.
- Mesh – handy for creating segments off your main substrate to adhere later. You need to ensure it’s non alkaline – also known as alkali-resistent – mesh as it avoids it degrading when being used with cement.
Glue / adhesive / grout
- Powder adhesive (exterior) – use white if going behind transparent glass and you can buy a mortar tint (I use Mortar Tone from Toolstation or similar) in black if you want to darken it. Lately I like Mapei Keraflex. I use grey mortar and tint it with the black Mortar Tone. While adhesive takes a bit of getting used to, this is my recommended adhesive to use for all exterior mosaic work.
- Titebond II / III (Amazon). (Note: When I first attended a course to learn about exterior mosaics, I was taught to use exterior PVA and used it for many years successfully. However, having taken on board insights from other mosaicists since then, I no longer use PVA even if it’s exterior grade nor do I recommend it for exterior use. So, if you are using exterior grade PVA, I recommend you switch to Titebond II / III.)
- Grout – exterior quality (the colour charcoal by Mapei goes well with slate or black is good either). (For grouting interior mosaics, I recommend a mid-grey colour as a good option if you’re unsure.)
Tools
- Wheeled tile cutters – my favourite are Leponitt but you can get budget ones in B&Q/Amazon etc
- Tile nippers
- Wheeled glass scorer – for scoring stained glass. My favourite are Toyo cutters. I use a pencil grip but often beginners in my classes prefer the pistol grip
- Runner (for snapping scored glass)
- Glass cutting mat
Suppliers (I’m based in Central Scotland, so some of the suppliers are located there)
- B&Q (grout, wheeled tile cutters, adhesive, tile nippers, plastic gloves)
- Screwfix (adhesive, grout, but you can get these online too).
- Toolstation (Mortar Tone, grout)
- Amazon – Titebond II / III.
- Direct Slating Supplies (slate) – Dennyloanhead near Falkirk
- www.thecraftyglassbox.com (for mosaic supplies in the UK – tiles, glass, etc)
- Creative Glass Guild for stained glass in the UK – www.creativeglassguild.co.uk
- Mosaic Workshop in the UK – good for tiles, hammer/hardie, smalti, gold smalti etc – https://www.mosaicworkshop.com
Rhona Duffy 