Negative screen printing follows a two-step procedure:
- Printing of Satin Ink.
- Printing of Satin Pro.
The first step is common screen printing and does not need further explanation. Here we analyse in details the second step.
Check temperature of paste and glass (about 30°C).
Clean and degrease glass before printing. Use hot water, alcohol-based glass-cleaners or other degreasing products.
Satin Pro is a thick paste, but its viscosity can be varied adding Satin Diluent.
The particular formulation of Satin Diluent allows changing Satin Pro density to meet different production requirements with no loss of etching power.
Before using Satin Pro, mix paste and diluent (max 10%) until the compound is homogeneous.
To get the best etching, it is necessary to apply a homogeneous and regular layer of Satin Pro.
We recommend a screen with a fabric made of polyester with 43 / 77 / 90 / 120 threads or 110 / 196 / 230 / 305 meshes.
Meshes with thicker knits give finer details, but a thinner etching too.
Using 120 threads / 305 mesh fabric, the glass acquires the sandblasted effect.
We recommend using a screen with a frame bigger than the drawing (at least 15 cm per side) to allow the fabric to stretch well and get a good printing.
Screen must be built using a water- and acid-resistant emulsion.
Satin Emulsion has been especially developed for this purpose.
Use a soft rubber with a hardness of 60/65 Shore.
The use of rounded rubbers provides a thicker layer of paste on the glass and guarantees a deeper etching.
Apply Satin Pro holding the squeegee with an angle of about 23° perpendiculars to the printing table.
To etch a glass surface, remove the paste after 5 minutes.
A shorter period gives a less etched effect. A longer interval does not result in a deeper etching.
Satin Pro must be left in place for 5 minutes. After 5 minutes, wash the glass using water.
Do not reuse the paste that has been in contact with water.
Typical result is an equally and uniformly etched surface from a medium to a high opacity level.
To best check the uniformity of etching, look through the glass towards a bright source while moving it.
If the level of etching is not sufficient, this can depend on several causes:
- wrong glass temperature;
- etching time too short;
- Satin Pro contaminated with water (never pour water into the paste and always dry the glass before etching).
Opacity must be regular without rings or stripes.
Rings may appear on the etched surface in case of insufficient cleaning or degreasing of the glass before etching.
Screen can be cleaned with water.
Use plastic spatulas only. Never use glass, ceramic or metal spatulas.
Etching is a chemical reaction and it needs a minimum temperature of 23°C.
We recommend to store Satin Pro in a warm and dry place and not to use it on cold glasses.
Put the can in a hot water-bath to allow the paste to reach the correct working temperature (30°C).
Do not exceed 35°C. Exposure to higher temperature can lead to an uncontrolled etching and it may cause safety problems.
Satin Pro can crystallize inside when stored for a long time in a cold place.
Do not use the crystallized paste as this may cause irregularities in the etching.
Crystals over the surface can be removed with a spoon. Crystals inside the paste, instead, meld spontaneously as soon as the can is stored in a warmer place for a few days.
The paste contains acids. Always use gloves and safety glasses.
In case of an accidental contact with the eyes, soak immediately with water and take counsel from your doctor.
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