Can be applied on underglaze ceramic and tile surfaces that are either leather-hard or bisque-fired.
Sheet size: 10x34 cm
Contains 7 individual 9 cm long decorative patterns.
Preparation and Storage
Since materials may behave differently under varying conditions, it is essential to perform test samples and a trial firing before beginning full-scale application. Store your transfer papers in a dry, dark environment, preferably in a sealed bag.
Apply to bisque-fired products. Can also be used on leather-hard clay and bisque surfaces.
CMC (Cellulose) Preparation
Before applying the design, it is important to properly prepare the CMC solution that will be brushed onto the surface. CMC (carboxymethyl cellulose), when mixed with water, forms a sticky consistency that helps the decal adhere uniformly to the surface.
Preparation steps:
- Slowly add 5–10 grams of CMC powder to 1 liter of warm water (about 50–60°C).
- Stir constantly to prevent clumping.
- Let the mixture sit until fully dissolved (it is generally recommended to rest for 12 hours).
- Once it reaches the desired consistency, it is ready to use. Apply a thin layer using a brush during application.
Applying the Decal Design
Design Preparation: Underglaze decal prints can come in various sizes. Cut the decal paper to the desired size as needed.
Placement: Place the printed, colored side onto the surface of the leather-hard clay or bisque where you want to transfer the design. Lightly press the paper with your fingers to adhere it to the surface.
Transfer Process: The design is transferred using the “water slide” method.
Application steps:
Place the decal covered with transfer lacquer into a container of water.
After about 30–60 seconds, the lacquered design will begin to separate from the backing paper.
If the decal is not yet fully ready, rest it on a towel for a while.
Applying Cellulose (CMC): Before transferring the design onto the surface, lightly brush the ceramic area with a thin layer of CMC solution. This step ensures strong and uniform adhesion. Avoid applying a thick layer.
Carefully slide the decal onto the cleaned and CMC-coated surface.
Ensure full contact between the paint and the ceramic surface; there should be no air, dust, or water trapped underneath, as this can cause the design to peel or burn during firing. During application, use a squeegee (often called a “fil ear”) to remove excess water, and gently blot the surface with paper towels. Any bubbles should be pushed out toward the edges; if any trapped air pockets remain, gently puncture them with a needle to release the air.
Firing Process
The firing process for screen-printed decals should be carefully controlled:
After application, all foreign materials on the surface should be removed to ensure proper transfer from paper to ceramic.
Underglaze decals should be fired at 1000°C to permanently fuse them with the ceramic surface.
Common Issues and Key Considerations
Gaps: Incomplete adhesion, dirt, grease, or fingerprints on the surface may cause blank areas on the decal after firing.
Shrinkage: Improperly prepared or overly thick decal paint, combined with damp conditions and rapid heating, can result in uneven shrinkage in some parts of the design.
Surface Bubbles: Firing too quickly can prevent proper vitrification of the paint, causing small craters and burst bubbles. To prevent this, raise the kiln temperature gradually at first—up to 350–450°C.
Conclusion
Underglaze decal (screen print) application is a widely used method that allows for clean, sharp, and vibrant decorative prints with the right preparation, careful techniques, and controlled firing. Always consider the variability of material behavior, perform test applications, and follow proper storage practices. This ensures the best possible results in both decoration quality and product longevity.