How to Make a Mosaic Coaster (Beginner Tile Craft)

The kit is short. You need a 10cm round MDF coaster blank, a small mixed pack of pre-cut glass mosaic tiles (the demo uses purple squares, red triangles, and green and yellow dots), a bottle of white PVA glue, and a small tub of white grout powder. Add a clean ceramic bowl and a teaspoon for mixing the grout, plus a soft cloth for wiping and buffing.

Pre-cut tiles are the secret to a beginner-friendly project. The edges are already smooth, so the finished coaster is safe to handle without anyone catching a knuckle on a sharp cut tile.

Wood that is not sealed will swallow any spilled drink and warp, which pops the tiles off later. Five minutes of prep now saves the whole project.

Squeeze a couple of drops of PVA onto the base of the blank. Dip a finger or small brush in water, then rub the PVA across the wood until it spreads thin and the surface feels slightly slippery. Cover the bottom and the edges. Skip the top - that side is getting mosaicked and does not need sealing. Set the blank aside to dry.

Once the seal coat is dry, flip the blank over and lay tiles out on the top face. Do not commit any glue yet. With pre-cut tiles you cannot trim a piece to fit a gap at the end, so you need to know the pattern works before anything is permanent.

Place tiles around the edge first, then work toward the centre. PVA grabs quickly once it touches the wood, and the tile you most want to move later will be the one that sticks down hardest. Settle the arrangement first, then glue.

For a small piece, less design beats more. The demo runs an alternating ring of purple squares and red triangles around the outside, then a band of green and yellow dots inside that, then repeats the pattern toward the centre. The repetition reads as a deliberate design instead of a busy jumble.

Once the pattern looks right, lift the outer ring of tiles aside in order so you can put them back the same way. You are ready to glue.

Pipe a thin line of PVA where the outer ring will sit. Resist the urge to lay it down thick - too much glue lets tiles drift while it dries and squeezes up between the tiles, which makes a grouting mess later.

Set each tile back in place one at a time. While the glue is still wet you can nudge each tile to match its neighbour. Once you are happy with the corners and the gaps, move on.

Work each row the same way: dry-fit, lift, glue, replace. With a mixed pack of tiles you want the colors evenly spaced. Avoid placing two of the same colour right next to each other, and keep the inter-tile gaps the same width as the outer row.

Once every tile is set, walk away. PVA needs a few hours to fully cure. If you start grouting too soon the tiles will shift under the pressure of your finger and the whole layout warps.

Spoon roughly three tablespoons of grout powder into a clean dry bowl. The exact quantity does not matter - you would rather end with leftovers than run short halfway.

Add water one teaspoon at a time, stirring between each addition, until the mix reaches the consistency of thick toothpaste. It should hold a peak on the spoon but still squish smoothly when you push on it. Too wet and it runs off the tiles before it sets. Too dry and it will not press into the gaps.

Drop a blob of grout straight onto the centre of the coaster, then work it across the surface with your finger so it pushes into every gap between tiles. Cover the whole top. Because the wood is sealed, grout that lands on the edges will wipe straight off.

Once every joint is full, take a damp cloth and gently wipe the excess off the tile tops. You are not aiming for perfect yet - just clear most of the grout so the colours show through. Leave the coaster ten minutes, then wipe again.

Once the grout is almost completely dry, the surface of every tile will be hazed with grey dust. Take a soft dry cloth - a clean hand towel is ideal - and polish each tile in a small circle. The dust lifts off and the colour pops out.

You should end up with crisp grout lines between every tile, all the same width, with no haze on the surface. That is the finished mosaic. Use the coaster as is, or brush a thin coat of clear sealer over the grout if you want extra protection against stains.