Jewelry Laser Welding: Filling Porosity
Tips for Filling Porosity with a Laser Welder
Porosity on Surface
Porosity when viewed from the surface, may appear to be a hole or pin-hole. Below is an example of deep porosity viewed from the surface of a ring shank.
Cross Section of Subsurface Porosity
Deep porosity may actually be an open pocket under the surface of the metal and may also contain impurities. Below is an example of a cross section of deep porosity.
Clean Out the Hole and Probe for Additional Porosity
Set the LaserStar for the porosity setting in the alloy you wish to fill. Fire the LaserStar at a 90° angle into the porosity hole. Larger holes may need several shots. This process will burn out any remaining investment or impurities trapped within the porosity hole and will also expose any other subsurface porosity. This step will also reshape the hole for easier filling.
Hold the LaserStar filler wire of the same alloy at a 30° angle or less making sure the tip of the filler wire touches the base metal. Fire the LaserStar at a 90° angle to the hole.
This will “puddle” the filler wire into the porosity hole filling the hole from the bottom up.
Make sure the hole is completely filled to slightly above the base metal. This ensures that the gauge of the base metal is not compromised during final finishing.
Hammering and Smoothing
It is now necessary to increase the Beam Diameter (Ø); this will reduce the depth of the weld resulting in a “Surface Weld.” Also, increase the Hertz (Hz), this will enable the LaserStar to fire more rapidly keeping the metal molten for ease of smoothing. Fire the LaserStar moving the item slightly in a back and forth motion. This will “feather” the metal across the fill zone resulting in a smooth hammering effect.
Clean up the area by filing, sanding or using a rubber wheel. Then polish and clean accordingly. Sample of finished ring shown below.