A step-by-step guide for successfully pretreating fabrics manually, with the use of a spray gun.
Pretreatment liquids are used to create a bond between the fibers and the ink, by filling in the spaces between the weaving of the fabric. When the fabric is cured, an invisible film is created that provides a smooth surface, ideal for the inks to be adhered upon and result in a high-quality print.
These solutions can be applied mechanically with an automatic pretreatment machine or manually using a hand sprayer. If a Wagner power sprayer or similar equipment is used, it is recommended to use the following steps in order to achieve the best print quality possible:
Use a well-ventilated area. Keep in mind that the pretreatment liquids contain chemicals, so the use of protective gloves and a mask is suggested. It's recommended to have the spraying area at least 3 meters away from a working printer.
Optional: Press the fabric or put it in the dryer as it is for 5 seconds. This step will help remove excess moisture from the fabric and smooth the surface, so that your print won’t have any wrinkles.
Before adding the pretreatment liquid to the sprayer’s container, shake the solution to avoid precipitation. Make sure that the sprayers’ nozzles are not clogged.
Learn how to properly maintain your pretreatment liquids.
Proceed to apply the pretreatment solution as equally as possible. Try to use the same direction when spraying and don’t overlap, the already sprayed areas, too many times. This could lead to some areas being overly pretreated and others having less pretreatment than required, which would cause an uneven print with patches. The amount of the pretreatment liquid applied depends on the solution itself, the type and the thickness of the fabric.
Tip: The recommended pretreatment amount for a 40cm x 60cm (15.7"x23.6") area (150 gr/m2 t-shirt), when pretreating dark cotton with the Texjet Inks - Pretreatment for Darks liquid, is about 21 to 25 ml. When printing on light cotton is 14 ml and on light polyester about 20 ml of the Texjet Inks - Pretreatment for Lights solution.
An item that would come in handy is a foam roller. A foam roller can help spread the pretreatment equally onto the fabric and improve uniformity. Use gentle strokes and not harsh scrubbing as this would take away some of the pretreatment and create wrinkles on the surface of the fabric.