VURA Robustner

VURA Robustner is a one component liquid product derived from ethyl esters of silicic acids. The product is converted into the natural binding agent silica gel and ethanol by the catalytic reaction with air humidity. Approx. 450-550 g of silicic acid gel is produced out of 1 Kg VURA Robustner.

CHARACTERISTICS

- Ready-to-use one component product
- Easy application
- Weather-resistant and non-yellowing
- Fluid consistency-good penetration
- Very high contents of active substances
- No closing of the pores, the stone retains its ability to breathe
- Transparent-colorless, therefore suited for light colored natural stones
- Solventless

APPLICATION AREAS
VURA Robustner is used to solidify absorbent mineral natural stones (sandstone, tuff stone, limestone etc.) or cast stones (stucco or fresco). The color of the stone is not intensified and the natural breathing properties of the stone are preserved

Usage Guide

PREPARING MEASURES
In order to achieve a successful solidification, it is important to first determine the condition of the object which will be solidified:

TEST FOR NOXIOUS SALTS (NITRATES, SULPHATES, CHLORIDES)
In case a large amount of these soluble salts is contained, the salt content must be reduced by several careful cleaning procedures with water (with compression). If the stone is very brittle, it may be sensible to harden the stone (if the salt content is adequately low) before cleaning it because intensive cleaning can result in a clear loss of substance. Pressure washers are not suitable for such cleaning work under any circumstances.

DETERMINATION OF DAMAGED STONE LAYER
An optimum solidification can only be guaranteed if more than the complete friable stone stratum is hardened. If not, shells may form and parts may chip off. Damaged stone has a higher porosity and therefore a higher water absorption. Extract a core from the stone to be treated and cut the core into slices. To examine the water absorption put the stone slices on well-watered foamed plastics. To compensate for the water extracted from the foamed plastics due to the capillary water absorption, they are put in a container filled with water. In intervals of an hour and during a whole period of 8 to 24 hours the specimen is weighed. Thus, the water absorption, porosity and degree of damage can be determined.

CLEANING
Rinse thoroughly with water after cleaning. The cleaning method used must suit the object concerned

CLEAPREPARATION OF A SAMPLE AREA
In case larger areas (façades) are to be solidified, we recommend preparing a sample area of 1-2 m² to examine
- to determine the material consumption as exactly as possible
- the efficiency of the product
- and to determine whether the object was hardened up to the healthy core of the stone efficiency and solidification depth can be examined according to the water absorbent method