COMPLIANCE INFO_2003-2005 - Laserfiche WebLink

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3, Adhesive working life Working life or pot life is the time it takes for the adhesive to harden in the mixing can. This time is measured from the time the adhe- sive and hardener are first mixed. Working life is shorter at tempera- tures above 70°F (21 °C) and be- comes longer as the temperature drops below 70°F (21'C). Work- ing life is affected by the quantity of mixed adhesive as well as by temperature. Use the following methods to increase the working life of adhesives: a. Occasionally stir the adhesive mixture during application. b. Cut the carton in which the adhesive kit is furnished so that the height of the carton is the same as the adhesive can. Line the inside of the box with rags or paper towels, and wet the rags or towels with solvent. Nest the can in prepared carton (See Figure 1.6.9). Do not contami- nate the adhesive with solvent. Caution: If adhesive becomes warm and starts to set up in the container, discard immediately. DO NOT USE THIS ADHESIVE TO BOND A JOINT! When adhesive is allowed to set up in the metal container, the con- tainer may reach approximately 400°F (2050C). Do not handle hot containers without heavy gloves. This exothermic reaction will gen- erate a dense smoke; therefore, the container should be placed outdoors in an open area until it cools. 1.6.4 Joint assembly 1. Bell and Spigot Joint -THE SPIGOT MUST BE ALIGNED AND LOCKED IN THE BELL. A cocked or misaligned joint will result in false lock-up and possible joint failure either during testing or at a later date. a. When the temperature is below 70°F (21 ° C), prewarm the bond- ing surfaces (after the joint has been cleaned and the cleaner has evaporated). Caution: Evaporation may be slow at extremely low temperatures. Use a hot air blower and apply heat uniformly to bell and spigot until warm (not hot) to the touch (See Figure 1.6.10). If torches are allowed on the job site (check local codes), use a clean - burning propane torch. Check temperature by touching out- side of the bell and inside of the spigot to avoid contact with clean bonding surfaces. If hot to the touch, let cool before applying adhesive. If an elec- tric heating collar is used to BLOW DRYER 1� BELL SPIGOT END END Figure 1.6.10 14 prewarm, place the joint to- gether dry, then heat the O.D. of the bell to avoid contaminat- ing the spigot. CAUTION: Do not use chemical heat packs for prewarming. b. Brush adhesive on both sur- faces, applying a thin uniform coating (See Figure 1 .6.1 1). Adhesive should always be worked into the machined sur- face by applying pressure dur- ing application. This will "vet out" the machined surface and maintain the required thin bond line. Be sure that adhesive is deep down into the bell past the insertion depth and that all ma- chined taper surfaces on the spigot and the cut end of the pipe are uniformly covered. Excess adhesive will make the joint more difficult to lock and can result in a flow restriction. Wet out the machined surfaces Figure 1.6.11 FE wn