Masonry Magazine March 1971 Page. 19
Cleaning Glazed Brick and Tile
Glazed brick and tile should be carefully wiped clean with a soft cloth, within a few minutes after laying. A final cleaning with a soft sponge or brush, with ample water, will usually do the job. The following is necessary only in more difficult cases:
Procedure A. Same as procedure A for Dark Colored Brick, except as follows:
1. Use no metal cleaning tools, brushes or abrasive powders.
Procedure B. Same as procedure B for Light Colored Brick, except as follows:
1. Use no metal cleaning tools, brushes or abrasive powders.
2. Use no more than one part high grade acid (CP) to twenty-five parts of clean water.
3. Acid should never be used in cleaning salt glazed or metallic glazed masonry units.
Proprietary Cleaning Compounds
During recent years the Structural Clay Products Research Foundation, a Division of the Structural Clay Products Institute, has investigated the effectiveness of some of the proprietary cleaning compounds now on the market both for cleaning new masonry and for removing other stains. Table 1 lists the compounds investigated. The absence of any commercial product from this list indicates only that it has not been evaluated by the SCPRF-SCPI Research Division. The classification (form) is based on the manufacturer's description and classification of his products. SCPRF-SCPI did not chemically analyze any of these proprietary materials. The following references to compounds listed in Table 1 are from the SCPRF-SCPI research report, Cleaning Clay Masonry. However, since the manufacturers of the products do not disclose their chemical formulae and are at liberty to change them at any time, the results reported are obviously applicable only to those products whose formulae have remained unchanged.
1. Dry Powder Form. Compounds 1, 2 and 3, Table 1, are sold in the form of a dry powder that is dissolved in water at the job site and used in the same manner as hydrochloric acid. The chief advantage of such compounds is their dryness. There is also less likelihood of spillage and the weight of water used to make the solution does not add to the shipping costs. Another advantage is the relatively low acidity. While this makes contact with the skin somewhat less dangerous, it makes the resulting solution slower than hydrochloric acid in removing mortar stains.
The chief drawback of these dry powders stems from their chemical composition. Their primary ingredient is sulfamic acid. This chemical forms weak sulfuric acid in water. Applying a solution of this to a wall may impart sulphates to the wall and thus may increase the possibility of
TABLE 1
Proprietary Cleaning Compounds
| No. | Product be removed.