A Remedy for Tile Troubles And Preparing Cement for Paint

Q. I have ceramic tiles in my kitchen, some of which have decorative decals applied to them. How do I remove these decals without damaging the tile?

- T.G.,

via e-mail

A. "Decorative decals on tiles are difficult to remove," says John Rarick at Reusche & Co., a color manufacturer for glass and ceramics in Greeley, Colo. "If they are 'on-glaze' decorations, they are fired onto the tile at a temperature of 1,350 degrees F." (Tiles are generally fired at 2,000 degrees F first, and then fired again along with decal decorations.) "The only way to remove such a decoration is with a heavy-duty acid cleaner such as Wink."

Beware, however, that you risk taking the glaze off along with the decals.

If your decals have not been fired along with the tiles, which is unlikely, then you could scrape them off with a razor blade.

Q. I'd like to prepare a cement surface for painting. Are there any other products besides muriatic acid that can be used and won't be toxic to plants and the environment?

- Via e-mail

A. Yes, there are environment-friendly preparations for cement and masonry, according to Howard Clark, project manager for Warfield Services Inc., a commercial builder in Natick, Mass. A painting-supply store, such as Sherwin Williams, carries a full line of these products.

"But if you are going to repaint concrete, there is no need to strip the prior coating first. A thorough scrubbing with a de-greaser/cleaner, followed by power washing to remove the loose paint, is adequate preparation for a new coat.

"If you choose a masonry stain, or are preparing new concrete for paint, etching is usually required. But the surface should be stripped of sealer, paint, or grease before etching is attempted. Dripping water on the concrete surface will show you if the etching liquid will work. If the drips stand on the surface instead of soaking into it, the etching chemical will not penetrate enough to be effective.

"Etching and stripping are not the same thing. Etching removes the salts and dissolved chemical effluents left near the surface by the concrete curing process or the evaporation of moisture. On the other hand, stripping only loosens the surface-borne coatings, such as paint or a sealer. Etching includes rinsing afterward, while stripping includes scraping.

"But remember that although the stripper selected may be biodegradable, the waste from the process often isn't. For example, exterior paints applied before 1978 usually contain lead."

Readers: Pose your questions and we'll seek out experts on home repairs, gardens, food, and family legal issues. Send queries to the Homefront Editor, The Christian Science Monitor, One Norway Street, Boston, MA 02115 or e-mail home@csps.com.