T.O. 33B-1-11-40Figure 1-7. Specific Gravity Hydrometer Readings for Two Water Suspended Developers.1.5.5.5.1Water suspended developers do not perform properly unless they wet the part surface and form a smooth, even coatingwhen dry. Lumpy or thick areas will hide small indications while uncoated areas will not provide developer action.Poor wetting is usually due to the addition of too much makeup water to replace drag-out losses or by contaminationwith oily materials which destroy wetting agents. It can also be due to developer age, since most of the newer wettingagents are biodegradable for pollution control purposes. To perform the coating test, use cracked chrome panels;ensure the panels are clean. Pour or otherwise apply some of the working bath developer and some of the referencestandard developer to the cracked chrome panels and inspect for signs of not wetting, such as pulling apart or formingbeads. The panel should then be dried and examined for even and complete developer coverage.1.5.5.5.2The developer may also become contaminated with penetrant. Fluorescent penetrant dye contamination can be checkedby visual examination of the bath surface with a black light. Uncontaminated developer appears dull white whilefluorescent dye contamination will show up as specks of yellow-green, floating on the top of the bath.1.5.5.6TestingWaterSolubleDeveloper.Water soluble developers reduce the number of in-service problems encountered with suspended developers sinceagitation is not required and the particles do not settle out. However, there are still concentration and contaminationproblems. Evaporation and drag-out will change concentrations during use, and the wetting agents can removeentrapped penetrant resulting in contamination. Water soluble developer SHALL be periodically tested to assureacceptable performance.
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