- Water source
- Sanded or unsanded grout
- Paint stick
- Apron or smock
- Disposable gloves
- Newspaper to cover work surfaces
How to Mix Grout for Mosaic Projects. The art of mosaic is a two step process. After you have mastered cracking the tile and adhering the pieces, you need to learn how to mix the grout. There is no precise recipe for mixing the perfect grout, but once you get the hang of mixing, it becomes second nature. The best part of grouting is when you wipe it off and reveal the magic of your mosaic!
Find a suitable place for the messy preparation, mixing, application and cleanup of grout. You'll need access to a water source both for mixing and cleaning, so generally outside near a hose is best. If you're not working outside, line the entire work surface and floor with newspaper to make cleanup easy.
Find a bucket for mixing the grout. A two and a half gallon bucket is suitable for smaller projects, while you'll need a five gallon bucket for tables and backsplashes.
Choose the right type of grout. Sanded grout is used for cracked tile mosaic projects where the spaces in between the tiles are an eighth of an inch or larger. Unsanded grout is for mosaics using stained glass or half an inch square glass tiles set closer than an eighth of an inch apart.
Select a grout color. Black or terra cotta colored grouts are perfect for outdoor pieces like flower pots, bird baths, stepping stones and paths because they do not show dirt or mildew. White is only good for artwork that is not functional in any way as it will get dirty quickly. Linen, tan and other colors, like blues, greens and yellows, are great for functional trivets and trays because they come clean and are especially decorative.
Mix your grout. For a small projects such as a 12 by 12 inch trivet or a medium sized tray you can fill your two and a half gallon bucket with about three inches of the grout powder. Grout consistency always mixes up differently depending on air humidity, time of day and brand of grout. A good deal of trial and error is sometimes necessary, but once you get it right, you will know what you're looking for every time.
Pour water into your bucket a little bit at a time. Use a large paint stick to stir the grout and water. It should look very dry and powdery and be a little difficult to mix at this stage.
Add more water slowly while stirring constantly to evaluate the consistency of the grout. You are looking for a peanut butter consistency. Test the consistency by dipping in your stick and turning it upside down. If the grout slides or falls off right away, your grout is too thin and wet and you'll need to add a little more powder. If it falls off in chunks, the grout is too dry and you'll need to add just a tiny bit more water.
Take your time adding water so you don't over water your grout and have to readjust the powder. Once you have practiced, mixing grout takes no more than five to ten minutes. Wear disposable gloves to protect hands and fingernails from color staining and dryness. Wear an old smock or apron to protect your clothes. Never wear good clothes because grout will stain and ruin clothes and shoes.
Never throw or wash used grout down any drains as it will harden. Wash your buckets outside in the grass with a hose. When opening the bag and pouring out the powder, wear a mask if you're susceptible to breathing problems or dust.