All sharp edges shall be ground to produce a radius and all imperfections, such as, skip welds, delaminations, scabs, slivers and slag shall be corrected prior to abrasive blasting. Skip welds should be welded solid.

Degrease surface prior to abrasive blasting by steam cleaning.

Abrasive Blasting:
NACE No. 1 or SSPC-SP5 or Sa 3 white metal.

White Metal Blast Cleaning - Removal of all mill scale, rust, rust scale, paint or foreign matter by the use of abrasives propelled through nozzles or by centrifugal wheels. A White Metal Blast Cleaned Surface Finish is defined as a surface with a gray-white, uniform metallic color, slightly roughened to form a suitable anchor pattern for coatings. The surface, when viewed without magnification, shall be free of all oil, grease, dirt, visible mill scale, rust, corrosion products, oxides, paint, or any other foreign matter.

Blast Profile:
4 - 6 mils as determined by Testex replica tape and measuring the results with a micrometer calibrated with NIST traceable standards.

Profile Density:
Check the blasted surface by comparing with Carboline’s blasted panel, using adequate light and magnification. Insufficient profile density is a common problem that is created by moving the blast nozzle faster than the propelled abrasive can create a uniform, densely pitted surface.

Correct dry film thickness is achieved by applying 3 multi-pass spray coats to produce the 35 to 45 mils dry film thickness.

Each coat needs to be cured prior to the application of succeeding coats. Succeeding coats cannot be applied without damaging the system until the surface temperature rises sufficiently to obtain partial polymerization. This will require raising to the minimum surface temperature of 70°F/21°C within 12 hours of application.

Metal temperature shall be recorded at least every hour and before application of coating. Humidity (wet bulb reading) shall be taken to ensure that metal temperature is at least 5°F/3°C higher than wet bulb temperature. Dry bulb temperatures shall be recorded at the same time to ensure curing.

Excessive dry film thickness is detrimental and can be the cause of micro-cracks and delamination in the dry film. Over spray, dry spray and surface contaminants must be removed prior to the application of successive coats to prevent the formation of pinholes in the coating film.

For immersion service, a pinhole-free film is essential and testing with Tinker & Rasor Model AP-W or Stearns Model 14/20 or equivalent is required on final film. Use 3000 to 3500 volts. Allow a minimum cure of 48 hours at 70°F/21°C or 36 hours at 90°F/32°C before holiday testing.

Dry film thickness shall be determined utilizing a non-destructive magnetic type high range gauge. We use electronic dry film thickness gages with memory that allow for the downloading of data directly into our server database. This provides a complete record of all dry film thickness inspection activity. All gages are checked for calibration with NIST traceable standards prior to all inspection acitivity.The anticipated film thickness shall be in the middle range of the gauge. The dry film thickness shall be a nominal 40 mils with acceptable minimum at 35 mils and maximum at 45 mils.

• The tank is 3,000 gallons/11,100 liters or larger.
• PLASITE 20 Thinner, up to maximum of 5% by volume, must be used for thinning purposes.
• The coating must be applied in 2 to 3 coats to a maximum DFT of 44 mils.
• Prior to placing the lining in service, it must be force cured at 200°F/93°C metal temperature for 4 hours.