Locate the problem and then select the possible cause to find a probably solution.
Porosity or Poor Solder Filling
Overheated Solder or Improperly Cleaned Alloy Surfaces
Clean alloy surfaces according to the technical guidelines and avoid oxide formation during heating. Uniformly heat solder and copings and use the correct fluxes.
Typically the joints being soldered and the solder are heated with the torch before the alloy turns cherry red. Melt the solder using the blue part of the flame so that the solder flows to the heated alloy surface. If fluxes must be used, avoid all boron fluxes and use fluoride fluxes.
Bridge Deforms Before Soldering Complete
Solder temperatures are often close to the fusion temperature of the alloy and special care must be used to assure proper soldering. Aurident suggests that:
Warm the abutment teeth before alloy turns cherry red. Do not overheat the teeth or they will deform. For longer span bridges, a support might be needed.
Melt the solder by running the torch up and down the solder until it begins to deform or melt. Heat using the area of the flame just outside the blue cone.
Continue heating the solder until it begins to drop and solder will fill joint.
Improper Filling or Connection
Insufficient solder used to fill void or wrong type of solder used. Be sure to consult with the catalog for solder types compatible with the alloy.