What you’ll need
Step by step
Get the background flat and clean
Glass shows every imperfection, so the background must be flat, smooth and clean. Skim or level uneven areas first.
Use a white adhesive and a fine notch
Use SUMO S02+ (white where the mosaic is clear) combed with a fine notch, so the bed reads evenly through the glass and there is enough adhesive without squeeze-out into the joints.
Bed for full, even coverage
Press each sheet for full contact and flatten the bed so there are no ridges or voids behind the translucent tiles. Beat gently with a flat board.
Align the sheets and set joints
Line up mesh- or paper-faced sheets so the joints run continuously between sheets, and keep them flush.
Remove facing (paper-faced), then grout
For paper-faced sheets, dampen and peel the facing after the adhesive grabs, adjust any tesserae, then grout once cured.
What to avoid
It shows through. Use a white adhesive for clear/translucent mosaics.
Trowel marks telegraph through glass. Flatten the bed for even coverage.
Glass reveals every dip. Level the background first.