Dow Dowsil 92-009 Dispersion Coating

Surface Preparation

In most cases, substantially stronger and more uniform adhesion is obtained by preparing the surface to be treated with DOWSIL™ 1200 OS Primer. The following steps are recommended for all surfaces except silicone rubber. (Silicone rubber surfaces should be roughened with sandpaper and then cleaned with acetone before applying the coating.)

Thoroughly clean and degrease the surface.

Rinse all cleaning agents off surface with acetone or methyl ethyl ketone.

After rinse agent has dried, apply a coat of DOWSIL™ 1200 OS Primer by dipping, brushing, or spraying. Typically, a very thin coating of primer will provide the best adhesion. If cracks appear in the chalked film, too much primer was applied.

Under typical room temperature and humidity conditions, the primer should be allowed to air-dry for 60 to 90 minutes. Because the prime coat is moisture sensitive, low humidity will necessitate a longer drying time.

Apply DOWSIL™ 92-009 Dispersion Coating.

Application

DOWSIL™ 92-009 Dispersion Coating can be applied by brushing, dipping, or pouring as supplied. If spraying is the preferred application method, the coating can be thinned with naphtha to any viscosity necessary for use with the intended spray equipment (see Mixing Recommendations). As supplied, the average build per coat is 5 to 6 mils.

For the smoothest coat, the following procedure is recommended: 1. Dilute the coating using a 1.3 to 1 ratio of naphtha to coating by volume (1 to 1 by weight).

2. Apply four passes in rapid succession per coat.

3. If extra buildup is desired, apply successive coats within 30 minutes after the preceding coat was applied. If this is not possible, allow the coated surface to air-dry four hours before applying the next coat.

Thicker coatings may also be achieved by using less naphtha

however, a rougher surface may result.

Pigmentation: DOWSIL™ 92-009 Dispersion Coating is easily pigmented for applications requiring color. To obtain good coverage, the pigment should comprise at least 3 percent of the total formulation by weight. When pigmenting the coating white, zinc oxide or titanium dioxide is recommended. Using the smallest available particle size will minimize settling problems. For other colors, silicone color concentrates–pigment dispersed in a silicone oil to form a paste material–provide the easiest application with the best results. Only two parts per 100 are required (see Mixing Recommendations).

Mixing

Any solvent or pigment added to DOWSIL™ 92-009 Dispersion Coating must be free of moisture to prevent premature gellation. This can be accomplished by adding the solvent or filler to the coating and rolling the combination in a closed container until thoroughly mixed, or by mixing in a commercial paint shaker. Zinc oxide or titanium dioxide should be dried 24 hours at 200°C (392°F) in trays before adding it to the coating.