CLEANING & REPAINTING METAL SURFACES
I. CLEANING PAINTED SURFACES
While the factory-applied finishes for hot-dipped galvanized steel sheets are so durable that they last years longer than ordinary paints, it will be desirable to clean them thoroughly on a routine basis.

Dirt pickup may cause apparent discoloration of the paint when it has been exposed in some dirt-laden atmospheres for long periods of time. Slight chalking may cause some change in appearance in areas of strong sunlight. A good cleaning will generally restore the appearance of these buildings and render repainting unnecessary. An occasional light cleaning will help maintain good appearance.

To maintain the original finish of the building panels, the only regular maintenance necessary is that of an annual washing. Mild solutions of detergents or ammonia will aid in the removal of most dirt, and the following are recommended levels.
1. One cup of Soilax®, or other common detergent, dissolved into five gallons of warm water.
2. One cup of household ammonia dissolved into five gallons of water (room temperature).
- The building may be washed with either solution, and the use of a well soaked cloth, sponge, brush (with very soft bristles), or low pressure spray washer are advised. (We do not recommend the use of scouring powders or solvents, since these agents may permanently mar the film.) Once the building is washed, thorough rinsing with clear water is necessary to eliminate the possibility of residue.

II. REPAINTING OF METAL BUILDING PANELS AND ROOFS
A. Surface Preparation
Any building panel surface to be repainted must be prepared and treated properly to insure continued performance of the coating system. The following four problem areas must be addressed before the repainting process can begin:
1. Dirt
Dirt, chalk and loose mildew can be removed by the use of common soap solutions. Heavier dirt accumulations may necessitate the use of a dilute solution of trisodium phosphate, and excessive mildew may be treated with a dilute solution of common bleach. (NOTE: Never blend cleansers and bleach.) Always rinse the surface thoroughly to remove any of the agents used in the cleaning procedure. Recommended detergents are Soilax® and/or Tide®, at a concentration of one cup for five gallons of warm water.
2. Wax
There may be a layer of factory-applied wax on the surface of the siding. This material is used to protect the siding during transit, and failure to remove this material will result in poor intercoat adhesion, and - eventually - peeling or flaking. To remove this material, it will be necessary to wipe the surface with a rag saturated with Xylene (Xylol). This industrial solvent will facilitate the removal of the wax and assure maximum adhesion between the substrate and the repainted material.
3. Surface Imperfections
Minor scratches, which have not left the metal substrate exposed, can be lightly sanded or buffed to create a smoother surface. Care must be taken, however, not to expose the substrate. Once this exposed condition exists, the likelihood for rusting is greatly increased. Should the metal substrate be observed during this operation, see the following paragraph.
4. Exposed Metal and Rust
Exposed metal must be treated to prevent rust from forming. To do so, sand the general area lightly and use a high-quality primer* to protect the exposed metal from corrosion. Allow sufficient time for the primer to dry before applying the topcoat. If either red or white rust is evident scrape or brush away as much rust as possible and then sand lightly, removing all rust before proceeding. Where large areas of rusting or surface imperfections are evident, the relative economy of power brushing or sand-blasting should be considered. Sandblasting with 16-35 mesh sand will provide a commercially clean and well-abraded surface for painting. If such a procedure is undertaken, make certain that all dust from the abrading process is removed before priming the substrate.
5. General Surface Condition
The surface to be recoated must be abraded enough to guarantee adequate adhesion. If the baked enamel finish is too smooth, the repaint material will not adhere to it, and it is advisable to test a representative area of the building to evaluate adhesion. If poor adhesion is observed, the surface must be “roughed-up” by sanding (#400 mesh recommended) or powerwashing. It is imperative, of course that the enamel finish itself not be removed during this process.
B. Repainting
After the building has been properly prepared, it must be immediately coated with a direct to metal epoxy primer. After the primer has fully cured apply a compatible topcoat. The primer, and compatible topcoat, may be purchased from any major paint retailer. Follow the manufacturer’s instructions for application technique and cure time.
PRECAUTIONS
THESE FIELD-APPLIED COATINGS AND SOLVENTS ARE FLAMMABLE MATERIALS. Keep away form heat and open flames. Use normal precautions when handling. DO NOT USE ON WET SURFACES. For best results, do not apply when temperature is below 55°F or when temperature is abnormally high.

III. USE OF AIR DRY TOUCH-UP PAINT
A. Surface Preparation
The area to be painted needs to be clean, free of dirt, and lightly sanded with #400 mesh sandpaper to assure adhesion. Where bare metal is exposed, sand the general area lightly and use a high-quality primer* to protect the exposed metal from corrosion. Allow sufficient time for the primer to thoroughly dry before applying the topcoat.
B. Painting
1. Brush
While the touch-up paint is a very fast air-dry coating not ideally suited for brushing large areas, it does, nonetheless, serve well when used to “spot paint”. Use the paint as you would any other brushed coating, always working quickly to smooth out brush marks before the coating dries. Use lacquer thinner to clean the brush and other tools.
2. Aerosol Spray
Follow the instructions on the back of the aerosol spray can for proper agitation and thorough mixing. Apply multiple light coats of paint, allowing one-minute intervals between coats, until the desired hiding and color are achieved. Follow the instructions on the back of the spray can for proper storage and future use.

* Glidden® Galvanized Metal Primer #5229
PPG® Galvanized Steel Primer #6-209
Dean and Barry® Latex Galvanized Metal Primer

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