Soldering natural titanium zinc
There are various brands of soldering flux “suitable for titanium zinc”, which can produce good soldering results. We recommend using soldering fluxes for new and old zinc.
These soldering fluxes must have the following properties:
• The zinc is scarcely or not corroded after the soldering.
• Do not produce harmful vapors.
• The flux residue can be easily removed.
• Do not cause rust on tools.
Soldering flux application process:
• Apply soldering flux to the top of the bottom sheet where the soldered joint is to be made. Make sure there is a 10 mm overlap to create a strong joint.
• Apply soldering flux to the bottom surface of the top sheet.
• Place the top sheet on to the bottom sheet and apply the top sheet with soldering flux. Make sure that you also cover the joint.
• Solder the materials together using a hot bit and 50/50 or 40/60 solder. Use a bit with a weight of 500 to 750 gram.
• Carefully remove any remaining soldering flux with a damp sponge or cloth.
It is especially advisable not to work with hydrochloric acid whether or not mixed with soldering flux, as this is harmful to the health, tools and the zinc. Before applying the soldering flux, ensure that the zinc surface is clean and that the lap to be soldered will close properly. The maximum permissible gap is 0.5 mm. When the soldering has been completed, the joints must be cleaned as quickly as possible with a damp sponge or cloth.
For soldering the zinc two alloys are recommended:
• Tin-lead 50/50, low in antimony, melting range 183-216 °C.
• Tin-lead 40/60, low in antimony, melting range 183-235 °C.
A lower temperature results in insufficient heat transfer, which causes ‘clumps and blisters’ to form between the joint. A higher temperature results in the tin burning or the zinc recrystallizing (annealing). The lead in the alloy is just a filler. The percentage of tin determines the melting area and the tensile strength of the solder. Solder with a low level of antimony must be used to solder zinc. Antimony causes a granular solder joint and increases the melting area.