Applying Brite Zinc by Brush or Roller
Currently, the Brite Zinc datasheet says that the bulk form of the product (B-200) is ready to be applied "as is" from the can by brush or roller. This is the case if you use the product up quickly (i.e., one hour or less). However, if you plan on using gallons or quarts over the course of a day, then you should thin it with Xylol or Xylene (available at most industrial paint supplies and Home Depot) to help it maintain a workable viscosity. For the gallons, use 1 quart Xylol/Xylene per gallon and use 1 pint per quart. In addition, stir the paint every 15-20 minutes while sprinkling in a little of the Xylol/Xylene. This will help allow the paint to be a little more workable while also maximizing your amount of coverage.
Paint Application and Humidity
A common-asked question at Brite is, "What's the temperature range that your product can be applied in?" Although surrounding air temperature is an important factor in successfully coating steel, humidity is equally, if not more, important. Applying a coating to steel when the relative humidity is too high can result in paint cracking, peeling, mudcracking, pinpoint rusting, and wrinkling. Those of you working outside in coastal areas are particularly susceptible to this phenomenon.
A good rule of thumb for the proper range for relative humidity developed by The Society for Protective Coatings (SSPC) is to apply the coating when the air temperature is at least 5 degrees F. above the dew point. The dew point is the highest temperature at which moisture will condense on surface and is typically listed in weather reports or can be measured using a battery-powered psychrometer. The dew point should be measured regularly throughout the day to ensure the coating is being applied in the proper range of relative humidity and avoid these failures. Another rule of thumb is to avoid painting on the days when relative humidity is >85%. This is because Brite Zinc is an air-dry coating and the residual moisture during cure may adversely affect adhesion to the substrate.
A common concern of applicators is if a coating is being applied "thick enough." The truth is, though, applying a coating too thickly is just as harmful as applying it too thinly. Applying a coating too thickly can entrap uncured solvents, cause internal stressing, cracking, and delamination. For Brite Zinc, we recommend a dry film thickness (DFT) of 1.0 - 3.0 mils. Anything less or more runs the risk of coating failures listed above. Measure the DFT using either a magnetic dry film thickness gauge (just put on dry film and thickness will appear on screen) or banana pull-off gauge. These gauges are available through industrial paint retailers.
When using our products, a key determinant of its success is the surface preparation of the base steel. For Brite Zinc, the two areas of most concern for surface preparation are making sure that the steel is free of dirt, grease, oils, and scaled rust. To address these issues, we recommend following the SSPC standards for surface preparation in these areas:
Contact the SSPC at (877) 281-7772 if you need more information regarding these standards and be sure to check out our SURFACE PREP for more guidance.
Clearing Aerosol Nozzles
The primary cause of clogged aerosol cans is due to failing to clear the nozzle after use. Failing to clear the nozzle will allow the zinc dust to settle in the valve stem causing it to clog. Therefore, to avoid this problem, be sure to clear the nozzle after each use by turning the can upside down and spraying 2-3 seconds until the can sprays clear. This indicates that all zinc dust has been evacuated from the valve stem and will eliminate any can clogging problems you have. If you have any existing cans that are clogged, then remove the existing nozzle and replace it with the nozzle from a new can and you should be able to spray out the remaining paint in the can.