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User Manual
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Palladium can be welded using the Orion welder, however, cracking can occur .
Palladium cracking is an especially difficult phenomenon to overcome with laser or pulse arc
welding . If only one weld spot is made, cracking will typically not occur unless the weld joint
is stressed by hammering, etc . This means that welding over porosity in a (Pd) piece can be
accomplished with the Orion to help clean up the metal during the finishing process . However,
welding more than one overlapping weld will inevitably lead to cracking (laser or pulse arc welder) .
Palladium cracking can be thought of as a combination of hot cracking and new weld puddle
crystal structure problems . After a weld, the molten (Pd) re-crystallizes, typically forming a large
and weak metal grain structure . When welds overlap, the new crystal structure in the last weld
puddle is weak compared to the original metal . The result - a crack will start at the edge of the
new weld where it overlaps with the old weld joint as the new weld cools and is stressed . The
crack will then run along the middle of the weld puddle in the direction of the overlapping joints .
This cracking is due to the stresses created during the weld puddle cooling process as described
above with hot cracking . However, this time instead of geometry causing the cracking, a rip starts
in the old crystal structure and propagates during the cooling process, much like ripping a piece of
paper . The result – (Pd) is difficult to weld successfully without breakage . Typically, single spots
of porosity can be welded and fixed but overlapping welds will crack .
There is a welding solution that can stop this cracking process . The addition of gold fill wire to
the weld joint creates a new alloy and stronger crystal structure . The gold can discolor the weld
joint . However, by welding over the joint several times the gold will diffuse into the (Pd) . Another
possible solution is to use a high gold content white-gold (Pd) alloy laser wire .
Silver (Ag)
Silver is an interesting metal with several properties that must be considered during the welding
process . First, silver is highly reflective over a large range of light wavelengths . This metal
characteristic makes welding silver difficult for a laser, but poses no problems for a Pulse Arc
welder . Second, silver is a very mobile metal when in a liquid state and has low surface tension
when compared to other metals . Because of these properties, how the weld energy is applied to
silver is important .
When welding silver it is important to understand the concentration of your weld energy relative
to the size of the silver being welded . For very small welds, a sharp electrode poses no problem .
This means that in the Orion’s arc mode, silver will typically behave well even with a concentrated,
focused beam of energy (i .e . a very sharp electrode tip point) . However, as the desired spot size
gets larger (bigger arc mode welds and almost all pulse arc mode welds) the liquid silver is easily
pushed around by the welding pulse . This will lead to large blobs of material being displaced
from the weld site resulting in a noticeable hole . To avoid this problem, simply un-focus the weld
energy by creating a truncated electrode tip flat . The size of the flat depends on the size of the
weld . For relatively small welds a small flat is all that is required . For very high energy welds the
electrode may be completely flat (1mm diameter) .
Resistance welding silver in tack mode is very difficult because of silver’s high electrical
conductivity . Sterling silver has a high electrical conductivity very similar to that of copper .
However, Argentium silver is approximately 30% less conductive . This means that more heat
can be generated during the spot welding process due to the additional material resistance . Use
Argentium silver if your application requires spot welding as opposed to pulse arc welding . Even
while pulse arc welding it may be desirable to use Argentium silver because of its superior tarnish
resistance . Thin Argentium silver parts can be welded directly using copper electrodes . Thicker
