Hidraulic tiles were widely used in Brazil, before the arrival of glazed enameled ceramic tiles.
Here we will show how decorative tiles were made, used as pavements in buildings. Today tiles are still used to pave sidewalks, but are of a different kind from that we will describe now.
The basic instruments to make a tile are steel objects called plate, frame and lid. The model, which defines the mosaic, is made of brass.
The mosaics are craftly made, one by one, patiently. A regular one, used on sidewalks, takes one minute to be made; one with drawings of several colors takes about five minutes or more to be concluded.
The process of making a mosaic is the following:
1. The plate, of polished steel, measuring one centimeter more than the future tile, is greased with a fluid, a mix of kerosene and mineral oil, at the ratio 3:1.
2. The frame is superposed to the plate. It is responsible for definition of the tile external shape , e. g., a 15 cm (6 in.), 20 cm (8 in.) , 40 cm (16 in.) square; a 15 x 25 cm (6 x 10 in.) rectangle (used in stairs).
3. The model is a piece with compartments which will hold the dyes of many hues, not allowing them to mix up.
4. The dyes are placed in the compartments, according to de tile design.
5. After all compartments are filled, the whole set is stirred so the paste is equally spread, and the model is immediately taken out of the frame. As soon after this, a drier substance, made up of portland type cement and fine sand, at the ratio 1:1.
6. Over the drier is applied mortar made with sand and portland type cement at the ratio 5:2 (2.5:1), with very little water.
7. The lid is incased to the frame.
8. The set is put under a manual press, which applies 5,000 kg (11,025 lbs) over the lid, and therefore to the tile.
9. The tile is unmoulded and is placed to be dried on a shelf. It cannot be piled.
10. After dried, on the next day, they are sunk in water for 24 hours. Then they are piled vertically, and from there, ready to be laid as floor tiles.