Grouting mosaics can be a big job. This is especially true in mixed media mosaics created from various types of materials which are combined and applied to one mosaic substrate. Some tesserae must be covered with tape or painted with sealer for protection from the abrasive and chemical qualities of the grout, while others must be "excavated" due to the various thicknesses and depth of tesserae, which result in different heights and levels on the final surface. It is easy to "lose" individual tesserae in the grout when surrounding tesserae are thicker and higher.
In this case the old plates and tiles were all different thicknesses and needed a lot of excavating; the millefiore, which are highly porous and can get clogged with grout, needed to be protected with a sealer from the sanded grout and then carefully excavated; and the mirror needed to be completely taped off to protect it during grouting. The silver backing on mirrors is especially vulnerable to corrosion from glues, adhesives and grouts so special mirror mastic must be used to adhere it to substrates in addition to providing it with a protective cover during grouting.
A light, neutral color of "antique white" grout was chosen to "blend" in with the background so that the delicately colored flower tesserae and bright pink ribbons would be highlighted as the main focal points of the piece. After the grout has been cleaned and is dry, several coats of protective sealer are applied to it and the piece is polished with a cloth.
This particular piece took about 5.5 hours to grout and clean. Those are strips of blue painter's tape covering the mirror and each tiny piece of millefiore was coated with a PVA protector prior to grouting. Because many of the joints (spaces between tesserae) are wider than 1/8", sanded grout was used.
To see the finished piece, click here