Surface Preparation
Next to the proper selection of a coating system, surface preparation is the most important procedure in the use of industrial coatings.

Although, many of the coatings listed on this web page are “surface tolerant, moisture insensitive or underwater coatings”, the overriding factor is that the better the surface preparation, the better and longer lasting the performance!

The methods referred to on this web page have been established by the American Steel Structures Painting Council, and others, as level of cleanliness prior to coating.

These standards can be translated to the equivalent European standards, but we have in the English version of our Web page, chosen to continue to use the American standard as recommended by the supplier. (our swedish web pages give the equivalent swedish and european standards as comparsion)

1. SSPC-SP 1: Solvent Cleaning; removal of oil, grease, dirt, soil, salts and contaminants by cleaning with solvent, vapor, alkali emulsion or steam.

2. SSPC-SP 2: Hand Tool Cleaning; removal of loose rust, loose mill scale and loose paint to the specified degree using hand chipping, scraping, sanding and wire brushing.

3. SSPC-SP 3: Power Tool Cleaning; removal of loose rust, loose mill scale and loose paint to the specified degree by power tool chipping, descaling, sanding, wire brushing and grinding.

4. SSPC-SP 5: White Metal Blast (NACE 1, SA 3); removal of all visible rust, mill scale, paint and foreign matter by blast cleaning with sand, grit or shot.

5. SSPC-SP6: Commercial Blast (NACE 3, SA 2); grit blasting to a high, but not perfect degree of cleanliness. Blast cleaning until two-thirds of the surface area is free of all visible residues.

6. SSPC-SP 7: Brush Off Blast (NACE 4); blast cleaning of all except tightly adhering residues of mill scale, rust and coatings, exposing numerous evenly distributed flocks of underlying material.

7. SSPC-SP 8: Pickling (Acid etching); complete removal of rust and mill scale using sulfuric, hydrochloric or phosphoric acids, followed by water wash to remove any residue. Can also be used in diluted form for preparing concrete.

8. SSPC-SP 10: Near White Metal Blast (NACE 2, SA 2½); blast cleaning to white metal cleanliness until 95% of the surface is free of all visible residues.

9. SSPC-SP 11: Power Tool Cleaning to Bare Metal; power tool cleaning to obtain bare metal surface and to produce or retain a profile. This procedure goes beyond SSPC-SP 3 in that it requires complete removal of all visible traces of oil, dirt, grease, rust, mill scale, paint or other corrosion products and foreign matter. If the original surface is pitted, slight residues of rust and paint may be left in the lower portions of the pits. If the surface needs to be roughened, the profile produced shall not be less than 25 µm in depth and suitable for the material selected.

Surface Profile
In conjunction with surface cleanliness is surface profile, which is defined as the measurement of roughness resulting from blast cleaning. The profile depth is a measurement from the lowest valleys of the surface to the highest peaks. The profile depth is dependent on the size, type and hardness of the selected blast media, as well as the velocity, pressure and hardness of the surface. In general, for thin film coatings up to 750 µm per coat, a profile depth of at least 75 µm is required. For thicker trowel grade materials, a profile depth of at least 100 µm is required.

Mixing
Proper mixing is essential for achieving a consistent and uniform coating.

The following procedures will help insure proper mixing:

1. Pour the two components into a clean container of ample size to properly mix the materials without spilling. Make sure that all of the material, Base and Hardener, is removed from each of its containers.

2. Mix the material, Base and Hardener, until a consistent, uniform and streak free consistency is obtained by the use of a paddle, spatula or power mixer.

3. Pour this mix into another clean or original container (if applicable), scraping all of the mixed material into this container and re-mix.

4. Repeat the above procedure 2 – 3 times before using.

Application
In general, once the surface has been properly prepared, it shall be inspected to insure that it is free from moisture, that it is above the minimum application temperature for the material and that the surface is at least 3 °C above the dew point.

Coating can then proceed by airless spray, rolling, brushing or trowel as specified for the product.

Recoating
When applying more than one coat, it is extremely important that recoat windows are followed.

In addition, the surface shall also be checked for moisture, dust, dirt or other contamination as well as for amine blush. Although most Duromar® materials are resistant to amine blush, anytime you have high humidity or low temperatures, this phenomena may occur. Amine blush is evidenced by a glossy and somewhat greasy exudate on the surface, which may dry to a chalky white colour. It is easily removed by using a 2% solution of hydrochloric acid or MEK.

Force Curing
Force cures are recommended for severe service conditions as both physical and chemical properties are enhanced. It can also be used to reduce the time to “full cure”. A general guideline of 4 hours at 80 °C will completely cure any of the Duromar ® products. Force cure shall not start until material has firmly set.

Engineering and Application Procedures Guide
A complete guide to the use and application of Duromar®´s 100% solids, zero VOC materials is available.