cup. Twist it slightly to ensure even coverage by the flux. Remove excess flux with a cotton rag. Support the tube and fitting assembly to ensure a uniform capillary space around the entire circumference of the joint.
7. Begin heating with the flame perpendicular to the tube, which conducts heat into the fitting cup. The extent of preheating depends on the size of the joint. Preheat the entire circumference of the tube in order to bring it up to a suitable temperature. (For joints in the horizontal position, avoid directly preheating the top of the joint to avoid burning the soldering flux.) Practice and experience will indicate the amount of heat and time needed. Next, move the flame onto the fitting cup. Sweep the flame alternately between the cup and the tube a distance equal to the depth of the fitting cup. Again, preheat the circumference as described above. Touch the sol- der to the joint. If the solder does not melt, remove it and continue heating. Do not overheat the joint or direct the flame into the face of the fitting cup, which could burn the flux and destroy its effective- ness. When the solder melts, apply heat to the base of the cup to aid capillary action in drawing the molten solder into the cup
We installed the filters using soldered copper to ensure the connections maintained strength and rigidity over time.
The central filter was installed on the floor to support its weight.