Preliminary Requirements

Safety Requirements

WARNING

IT IS THE RESPONSIBILITY OF THE OPERATOR TO OBTAIN AND OBSERVE THE MANUFACTURER'S MATERIAL SAFETY DATA SHEETS FOR CONSUMABLE MATERIALS. THESE CONTAIN INFORMATION SUCH AS, HAZARDOUS INGREDIENTS, PHYSICAL/CHEMICAL CHARACTERISTICS, FIRE, EXPLOSION, REACTIVITY, HEALTH HAZARD DATA, PRECAUTIONS FOR SAFE HANDLING, USE AND CONTROL MEASURES AND ALSO TO TAKE LOCAL REGULATIONS IN TO CONSIDERATION.

Procedure

1. SUBTASK 70-22-03-220-001 Procedure

   1. Use one of these procedures to measure the surface condition:

      NOTE

      The replicating compound procedure is intended to measure the shape and dimensions of surface conditions (for example, pits, gouges, and scratches) that are larger than 0.010 inch (0.254 mm) in diameter and/or 0.005 inch (0.127 mm) in depth.

      NOTE

      The replicating compound procedure uses a polyvinylsiloxane or silicone rubber impression material system (used for dental impressions) that has a paste- or putty-type base component that you mix with a catalyst component to make the replicating compound. The replicating compound molds to the part surface to make a replica (copy) of the part surface.

      NOTE

      The polyvinylsiloxane or silicone rubber impression material is available in different viscosities as systems that you mix by hand, or as systems that have a cartridge that keeps the base and catalyst components of the impression material apart in different chambers, and a gun-type device called an "extruder gun" or "cartridge dispenser". The gun holds the cartridge, and uses a plunger to push the base and catalyst components out of the cartridge through the mixer tip that mixes the two components together as you extrude or dispense the replicating compound on the part surface.

      1. Replicating Compound (Polyvinylsiloxane or silicone rubber Impression Material) Procedure.

         1. Clean the part by the applicable cleaning method. Then, clean pitted or scratched surfaces fully with a clean cloth moistened with a solvent from SPM TASK 70-11-26-300-503. You can use a bristle brush to remove remaining material from the bottoms of pits and scratches.

         2. Apply the replicating compound by one of these procedures:

            NOTE

            CoMat 02-379 POLYVINYLSILOXANE IMPRESSION MATERIAL KIT and CoMat 02-379 POLYVINYLSILOXANE IMPRESSION MATERIAL KIT are kits that include impression material cartridges and mixer tips. Spare mixer tips are available as CoMat 02-382 MIXER TIPS.

            NOTE

            CoMat 02-379 POLYVINYLSILOXANE IMPRESSION MATERIAL KIT has a low viscosity and CoMat 02-379 POLYVINYLSILOXANE IMPRESSION MATERIAL KIT has a medium viscosity.

            NOTE

            It is necessary to use the CoMat 02-380 EXTRUDER GUN and a mixer tip to apply the CoMat 02-379 POLYVINYLSILOXANE IMPRESSION MATERIAL KIT or CoMat 02-379 POLYVINYLSILOXANE IMPRESSION MATERIAL KIT.

            NOTE

            When you use a CoMat 02-381 TIPS - INTRA-ORAL, DISPOSABLE SYRINGE you must also use a mixer tip. The CoMat 02-381 TIPS - INTRA-ORAL, DISPOSABLE SYRINGE is a curved tip that lets you apply the replicating compound at a angle to the longitudinal axis of the cartridge. It does not mix the components of the polyvinylsiloxane impression material.

            1. Use CoMat 02-379 POLYVINYLSILOXANE IMPRESSION MATERIAL KIT and the CoMat 02-380 EXTRUDER GUN to apply a layer of the replicating compound mixture over the area of the surface condition. You can install a CoMat 02-381 TIPS - INTRA-ORAL, DISPOSABLE SYRINGE on the mixer tip to apply the mixture to areas where access is difficult.

            2. NOTE

               CoMat 02-384 POLYVINYLSILOXANE IMPRESSION MATERIAL KIT has a low viscosity and CoMat 02-384 POLYVINYLSILOXANE IMPRESSION MATERIAL KIT has a medium viscosity.

               NOTE

               The applicable extruder gun and mixer tips are available from the polyvinylsiloxane impression material manufacturer.

               Use a CoMat 02-384 POLYVINYLSILOXANE IMPRESSION MATERIAL KIT with a mixer tip and a CoMat 02-380 EXTRUDER GUN to apply a layer of the replicating compound mixture over the surface condition to be measured.

               NOTE

               CoMat 02-385 POLYVINYLSILOXANE IMPRESSION MATERIAL PUTTY is a high viscosity putty.

            3. Use the manufacturer's instructions to mix the CoMat 02-385 POLYVINYLSILOXANE IMPRESSION MATERIAL PUTTY and catalyst, then apply a layer of the mixed putty over the area of the surface condition to be measured.

            4. Use CoMat 06-177 SURFACE REPLICATING MATERIAL cartridge with the applicable Dispenser Gun, Static-Mixing Nozzle, and Nozzle Tip to apply a layer of the replicating compound mixture over the area of the surface condition.

               1. CoMat 06-177 SURFACE REPLICATING MATERIAL has a very low viscosity.

               2. The applicable Dispenser Guns, Static-Mixing Nozzles, and Nozzle Tips are available from the replicating compound material manufacturer, Vendor Code R4723 or 5T799.

         3. Let the replica cure fully. This will usually occur in 4 to 5 minutes. Refer to the manufacturer's instructions.

         4. Lift the replica carefully from the surface.

         5. Examine the replica for dirt, scale, discoloration, and air bubbles. Do the full procedure again if you can see one or more of these conditions in the replica.

         6. Attach the replica to a round rod. The side of the replica that touched the part must be up (away from the rod).

         7. Install the rod on the stage of an optical comparator in a fixture that lets the rod turn on its longitudinal axis.

         8. Adjust the comparator stage to a position where the light source radiates across the top of the rod and replica, and casts a shadow on the screen.

         9. Set the comparator to an applicable magnification (for example, 50X magnification), and focus the image on the screen.

         10. Slowly turn the rod on its longitudinal axis until a condition of interest is at its maximum size on the screen. Measure the size of the condition on the screen, and convert it to actual size.

         11. Refer to SPM TASK 70-11-26-300-503 to remove all remaining replicating compound from the part.

      2. Replicating Tape Procedure.

         NOTE

         The replicating tape procedure is intended to measure the size and depth of shallow, open surface conditions (for example, pits, gouges, and scratches) that are not more than larger than 0.020 inch (0.508 mm) diameter. It is not usually applicable to measure deep, tight conditions (for example, cracks or re-entrant types of pitting).

         NOTE

         The replicating tape procedure uses CoMat 01-031 ACETONE (CH3)2CO to make a thin cellulose acetate tape soft, which lets the tape mold to the shape of the part surface to make a replica (copy) of the part surface.

         1. Clean the part by the applicable cleaning method. Then, clean pitted or scratched surfaces fully with CoMat 01-031 ACETONE (CH3)2CO. You can use a bristle brush to remove remaining material from the bottoms of pits and scratches.

         2. Cut a piece of the CoMat 02-378 TAPE, REPLICATING to a size that is sufficient for the area to be examined.

         3. Apply sufficient CoMat 01-031 ACETONE (CH3)2CO to make wet the area to be examined.

         4. While the surface is still wet with acetone, apply the replicating tape to the area to be examined. Work from the center to the edges to prevent air bubbles under the tape.

         5. Let the tape dry fully. The tape must dry for a minimum of 10 minutes.

         6. Lift the replica carefully from the surface. If the replica starts to tear (break), you can reinforce the replica with a layer of adhesive cellophane tape.

         7. Examine the replica for dirt, scale discoloration, and air bubbles. Do the full procedure again if you can see one or more of these conditions in the replica.

         8. Attach the replica to a round rod. The side of the replica that touched the part must be up (away from the rod).

         9. Install the rod on the stage of an optical comparator in a fixture that lets the rod turn on its longitudinal axis.

         10. Adjust the comparator stage to a position where the light source radiates across the top of the rod and replica, and casts a shadow on the screen.

         11. Set the comparator to an applicable magnification (for example, 50X magnification), and focus the image on the screen.

         12. Slowly turn the rod on its longitudinal axis until a condition of interest is at its maximum size on the screen. Measure the size of the condition on the screen, and convert it to actual size.

         13. Refer to the SPM TASK 70-11-26-300-503 to remove all remaining replicating compound from the part.

             NOTE

             The optical micrometer procedure is intended to measure the depth of corrosion pits.

      3. Optical Micrometer Procedure.

         NOTE

         It is not recommended to use a depth gage micrometer with a push-down point because the point on this type of depth gage does not always touch the bottom of small-diameter pits.

         1. Use an optical micrometer (for example, Model 966A (PN 125632)) with a 200X magnification, or use equipment with equivalent features and safeguards, to measure the depth of corrosion pits. This equipment is available from supplier 58949. Refer to List of Suppliers for source.

         2. If an applicable optical micrometer is not available, or if the optical micrometer cannot get access to the pit location on the part, measure the pit depth by replicating compound (polyvinylsiloxane impression material) procedure or the replicating tape procedure given above.