A release test or Rub-Out is a method to check the compatibility of a dye with a tinted material. This allows you to assess the color saturation of the finished paint, as well as check for the absence of defects such as: flocculation *, sedimentation *, syneresis * and several others. In most cases, the Rub-Out test is sufficient to decide on the use of a dye.

It is highly recommended to perform a test before using pigment paste for paint tinting.

Procedure:

1. Tint the material;

2. Apply the prepared mixture to the test card (indicating the tinted material, color sample and percentage of dye) with a 120 micron applicator (preferred method) or with a conventional brush;

3. Perform an abrasion check: immediately after the start of the layer polymerization (this time is different for each type of paint) rub the painted surface of the card with your finger;

4. The test cards thus prepared shall be dried to dryness;

5. Evaluate the result:

If there is no difference between the effortlessly applied coating area and the rubbed area, good compatibility;
If there is a slight difference in color and / or small stains – satisfactory compatibility;
If the color of the applied area and the rubbed area differ significantly, poor compatibility.

6. Attach the abrasion test results to the dye sample test report.

If an “incompatibility” (unsatisfactory compatibility) occurs, it is recommended to increase the “shear forces” by adding a dye to the tinting material (increase the time and / or mixing intensity) and to repeat this test in order to improve the compatibility.

In the photo: Rub-Out test results: on the left side there is a satisfactory addition of tinting paste to the tinting material, on the right side it is unsatisfactory.

* Flocculation – a reaction in which finely dispersed pigment particles are released in the form of large flakes or precipitate as a result of changes in the physical or chemical state of tinted coatings.
* Sedimentation – sedimentation of pigment particles in paint materials under the influence of gravitational field or centrifugal forces.
* Syneresis – separation of the liquid phase from the paint dispersed structure, which contributes to volume reduction.