Depth of Retardation

Vetotard XT428 is available in three etch depths. The material in every pail is color coded to show the particular depth of exposure.
Purple - light etch from 1 - 2 mm
Blue - medium etch from 2 - 4 mm
Black - deep etch form 4 - 6 mm
The above is a guide based on Grade 30 concrete, medium workability, 20 mm maximum size aggregate.

Usage Instructions

Vetotard XT428 should be applied in one even coat using a brush or roller. Coverage rate is 5 - 8 m2 per liter.
It is possible to spray Vetotard XT428 but would need to dilute with 5 - 10% water to achieve sprayable consistency. Stir well before use.
Before concrete is placed, the surface retarder should be dry for face-down application. This typically takes 15 to 60 minutes depending on ambient conditions whereas in the case of face-up, Vetotard XT428 should be applied immediately after placement of concrete is complete in wet conditions.
Immediately after the concrete molds are stripped, the retarded surface of the concrete can be exposed either by brushing and/or water washing. Water washing should be carried out using a high pressure water jet at between 1000 and 2000 psi (5 to 10 N/mm2). Dry brushing requires the use of a wire brush.
To bring out the full color of the aggregate for decorative finishes, wash the concrete face with a dilute solution of hydrochloric acid (5% concentration).

Cleaning
Clean all tools and equipment with water immediately after use.