Pooling usually occurs when you overheat the secondary metal before the backing metal reaches soldering temperature. The result is a loss of crisp edges and clean joins. Sinking occurs when the backing metal reaches a semimolten temperature, allowing the secondary metal element to sink into it. The result is that the secondary metal element looks as if it were almost an inlay. Both pooling and sinking are akin to fusing and indicate that the metal is being overheated.
It’s difficult and time consuming to clean up pooling or sinking scars around a secondary metal piece, but if you don’t correct the problem, it will get worse in subsequent soldering steps. If you have to clean up, do it after each soldering.
To clean up pooling and sinking scars, use sanding disks in a flex shaft. The disks come in coarse, medium, and fine grits. Use the edge of a new sanding disk to clean minor pools along the secondary metal’s join. Once the edge of the disk softens, it won’t get in crevices as well. Use the flat side of the sanding disk to smooth ridges along the silver’s surface, and then use consecutively finer grits to smooth the metal. You can also use burs to get into tight spaces, but take care not to create a bigger problem. Small files of assorted shapes are useful too; remember to use emery paper to smooth
over the file marks when you’re done filing.
Sometimes the secondary metal has melted so much that cleanup won’t be effective. Removing the secondary metal completely usually produces a deep scar in the silver backing that’s difficult to repair, but as a last-ditch effort, it’s worth a try. If removing the secondary metal is no longer an option, try hammering the secondary metal element into the backing metal and then sanding the top so it looks like an inlay.