T.O. 33B-1-12-65temperature reaches and remains at 140°F (60°C) for over ten minutes, the inspection sensitivity can be reduced. As aguideline remove the parts while they are warm but can still be handled with bare hands. This is a temperature ofabout 120-125°F (49-52°C).2.6.3 DryDeveloper.2.6.3.1 Description.Dry developers are characterized by their fluffy nature and low bulk density, i.e.; one pound of dry developer occupies 2or 3 times the volume that would be required for wet developer powders. Dry developers can be used with any type offluorescent penetrant but not with any visible-dye penetrant. They are loosely held on the part surface by adhesion.Dry developer particles are generally white. When the dry developer is applied to part surfaces, the coating layer isvery thin and uniform. In fact, dry developers leave very little visible trace, but their presence becomes readily obviouswhen a finger or rag is wiped across the surface. Dry developers SHALL NOT be used with visible-dye penetrantssince they do not provide adequate contrast.2.6.3.2 Application.WARNINGDry developer particles are not toxic materials; however, like any solid foreignmatter; they should not be inhaled. Air cleaners, face masks, or respirators may berequired. The Base Bioenvironmental Engineer SHALL be consulted if the processgenerates airborne particles.NOTEDry developers SHALL NOT be applied to a part until the surface and anydiscontinuities are thoroughly free of moisture. The presence of even a littlemoisture will interfere with the developer action and small flaws may be missed.Dry developers can be applied in a number of ways:a. Blowing the powder on with a bulb type blower.b. Immersing the part in a container of dry particle powder.c. Pouring the powder over the parts.d. Using a dust or fog chamber where the particles are blown into an air suspension.e. Spraying with an electrostatic system or a low pressure flock gun.2.6.3.2.1After application, the excess developer should be shaken off or removed with a hand air bulb or squeeze blower. Thedeveloper particles are not loosely held but care should be taken to not remove them during handling. Wiping,brushing, or compressed air in excess of 5 psig SHALL NOT be used. Care must be taken to prevent contamination ofthe dry developer. The two most frequent contaminants are water or moisture and penetrant. Water in dry developercomes from parts that have not been completely dried or from careless splashing during the wash step. Water ormoisture contamination will cause the dry developer to form lumps or to cake, thus reducing its effectiveness.Penetrant contamination occurs when particles of penetrant-soaked developer fall from poorly washed parts or heavyindications. Penetrant contamination will cause false indications either on the part being processed or on subsequentparts.
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