Following is some detailed application information for using Ferro's Soluble Salts.

Silk Screen
Before applying Ferro's soluble salts with silk screens, it is necessary to increase the viscosity of the original solution in order to avoid the diffusion of the product into areas printed by the screen.

The viscosity can be modified based on the application machine-flat or rotary-and the type of screen.

To increase the viscosity, it is possible to use two types of flocculants:

Flocculant SK-001
Used at 5% to 6%, it is necessary to dilute the flocculant with an ethanol disperser before use to avoid conglomerates.

Flocculant SK-003
Used at 1% to 2%. You don't need to use a disperser with this flocculant, and you can add it directly to the color during mixing.

Flocculation can be carried out in two ways:

a.) Flocculation with appropriate agent.

This is the best way to obtain a perfect dispersion, and it is also very quick.

1. Weigh into a container the quantity of color that is going to be flocculated.
2. Weigh into a second container the quantity of flocculant that is needed (5% to 6%), and then add in the same quantity of dispersing agent. Stir with a pallet knife to obtain a complete dispersion of the flocculant.
3. Add the flocculant/disperser mix to the soluble color, while stirring the entire mix with a stirring machine.
4. Continue stirring for 2 to 3 minutes, until the dispersion is uniform and perfect.
5. Stop stirring and allow the mix to rest for 10 to 15 minutes while the viscosity increases.

b.) Flocculation without a dispersing agent.

It takes more time to prepare the inks using this method.

1. Weigh into a container the quantity of soluble color that is going to be flocculated.
2. Weigh the amount of flocculant needed into a second container.
3. Slowly add the flocculant to the soluble color. Begin stirring the soluble color with a stirring machine, and continue stirring while slowly adding the flocculant, taking care to prevent conglomerates.
4. Continue stirring until the dispersion is perfect.
5. Stop stirring and allow the mix to rest for 10 to 15 minutes while the viscosity increases.

Note: Although the paste keeps its viscosity for several weeks, it is preferable to prepare the paste right before use and to store the liquid color separately. This is absolutely necessary when using SK-800.

Silk screen application of salts does not differ from the application of silk screen pastes containing glaze, but the usual additives and the vehicles commonly cannot be used.

All data and measurements indicated are only approximate and can be modified to obtain better application conditions according to the characteristics of the product, the graphic design and the equipment. The measurements of the application line should vary from a minimum of 70 meters to an optimal length of 90 meters.

It is recommended that a dryer be installed to control the temperature of the unfired tile before the various applications. The ideal temperature is 50º-60º C.

After the dryer, it is necessary to use a certain quantity of water (approximately 20 to 40 g for size 40x40 cm); this will increase the penetration of the color. An increase in the quantity of the water will favor the penetration of color but decrease the mechanical resistance of the raw tile. In the case of body with a high percentage of plastic components, it is recommended to keep the quantity of water low to avoid swelling of the clays. If the temperature is higher than 50º C, it is necessary to use a larger quantity of water to lower the temperature of the unfired tile. In this case, the quantity of water depends on the temperature of the tile because a part of the water is evaporated to lower the temperature. At the end of the application the amount of unevaporated water that remains in the tile should be approximately 20 g.

Silk screen application is used for the silk screen paste containing glaze. The silk screens used normally have 24 to 36 threads. The distance between the silk screen equipment must be such that this permits good penetration of color; normally 20 to 30 seconds are sufficient.

After the silk screen application, more water must be applied to increase the penetration of colors; normally 25 to 35 g of water is used for a 40x40 cm size. Checking of penetration is done in regulating the quantity of water. More water improves penetration but lowers graphic definition of silk screening. Maintaining a mechanical resistance of the raw tile higher than 20 kg/cm is recommended.

After the application of water, it is necessary to let the color penetrate for approximately one minute. This means that the tile must be dried in order to stop penetration. This treatment permits control of different shades.

Although the penetration of Ferro SK salts is constant, a light difference may be seen between the edge and the center of the tile caused by the different temperature of the two areas during the application. In order to avoid evaporation, it is not advisable to silk screen salts on tiles that are very hot.

The application of water, resting time and the accurate control of the temperature of the tile are of extreme importance in the control of the depth of penetration of the pigment which will influence the final result after polishing.

The penetration of the salt must be much higher in respect to the maximum thickness that must be polished, e.g. in the case of polishing from 0.3 to 0.5 mm it is necessary that the salt penetrates about twice as much. The colors can vary due to operating conditions and the correct fine-tuning of all parameters can only be obtained through experience.