Torrecid Glazura s.r.o. - Roudnice nad Labem

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Instructions and techniques

Direction for use of the glazes

The frits are granulated vitrifiables of a special composition with the addition of kaoline, ceramic pigments, colouring oxides, hardening mediums and other additives. They are designed for the refinement of the ceramic products surface, above all to the ensuring of tightness, to increasing of chemical and mechanical ruggedness and to improvement of aesthetic characteristics (colourfulness, lustre, etc.). The thermal expansivity of the burnt glaze should be conformable with the thermal expansivity of ceramic body, in order that it does not reach the crackle, springing-off eventually the product destruction. It is necessary to choose the glaze type with regard to demanded firing temperature, that depends on mass used.

Packing and stocking

The glazes are delivered standardly in dry conditions in the iron-plate casks with PVC-lining, in paper or PE-sacks, according to the delivered quantity. The storability of the dry glaze is not time limited, it is necessary to prevent from the access of moisture, dust and impurities. The disposed aqueous suspension should be stored for a short term, because they are added no conservative reagents by the production.

Operating sequence

We stir the dry glaze in the water up to thick paste, that we will dilute to density necessary. It is advisable to quiet the glaze and then strain through fine sieve. It depends the density for tha glazing on the glazing method and on the body absorbability. A thick porous body, that drains out the water quickly, demands the thinner glaze, than a consistent body with low absorbability or thin-walled body, that does not manage to drain out the water. We recommend to try every glaze in different layer thickness on the body and burn out in running conditions. The thickness of the glaze layer on the body should move till 1 mm, whereas the opaque glazes should be applied in thicker layer than the glazes transparent. By reason of decrease of glaze setting and the moderate fluidity adjustment, we recommend to use the electrolyte Ls 040 18 in the quantity of 1-2 ml at 1 kg of dry matter. It is possible to mix the glazes one another according to the individual demands on shade, meltability or art effects. The body has to be before the glazing clean, devoid of dust and fat, otherwise it contracts by the firing from these places. The usual temperature of biscuit firing at porous mass it as a rule about 50°C higher than the temperature of glaze firing. At earthenware it is sufficient the buscuit firing temperature about 800-900°C. In some cases, it is glazed on raw body and the goods is burnt once only. We can glaze by coating, soaking or spraying so that it will be created the even coat. Multicolour goods, we can brush. The glazed goods we have to dry well before the firing. The firing temperature has to answer to the data mentioned at the several glazes. At the decrease of the firing temperature, the glaze is matt, rough, no thro'molten enough and at the overfiring the glaze will seep to the body or flow off.

Safety at work

The glazes - above all the coloured - can contain the dangerous substances, e.g. heavy metals. At the work dangerous substances and preparations, it is necessary to abide by the data from products safety data sheets. It is necessary to pay the special attention to the work with the glazes containing lead oxides (noted in catalogue and on the cover). It is necessary to observe at the work the generally binding hygienic regulations.

Inspection and testing

Every production charge is tested in the technical control department according to the specified technical process, in agreement with quality manual. The test parameters are: fineness of grinding (the sieve residue 0,063 mm), moisture, surface appearance, colour variation from standard. On demand, we deliver to the glazes the conformity declaration.