Soldering: Joining metals by heating them to a suitable temperature and using a filler metal having a liquidus not exceeding 450°C (840°F), and below the solidus of the base materials. The filler metal is distributed by capillary attraction

Soldering is used to join metals. Dissimilar metals may be joined by soldering. When molten solder leaves a continuous, permanent film on the base metal surface, it is said to wet that surface. Without wetting there can be no soldering action. In order for wetting to occur, there must be a stronger attraction between certain atoms of the solder and the base metal than among the atoms of the solder itself. Intermetallic reactions usually take place at the interface between the base metal and the solder. Wetting is facilitated by the ability of a solder to alloy with the base metal. -- Soldering Manual 2nd Edition, Revised, American Welding Society, 1978

Johnson Manufacturing Company provides

to assist you in your soldering operations.

Johnson`s Soldering Fluid is recommended for general purpose soldering, but we also make a wide range of fluxes covering a variety of applications.

We produce both Lead Free solders, as well as Tin Lead Solders in a variety of wire diameters, bar solders and ingots.

We also offer a selection of Tools to assist your soldering processes including Brushes for flux application, Torches and Soldering Coppers.


Basic soldering steps

Joint fit up

Solder joints should be designed so solder can be drawn into the space between them by capillary action. A clearance of 0.15mm (0.005 inches) is suitable for most work.


A clean, oxide-free surface is required for a uniform quality and sound joint. Grease, oil, dirt and oxides should be removed prior to soldering


Apply flux to the surfaces to be soldered. It should accomplish the following:

  1. be fluid and remove the oxides and other non-metallic materials at soldering temperatures
  2. Provide a barrier to re-oxidation of the metal surfaces
  3. Permit displacement by the solder
  4. Promote wetting by the solder

Apply Heat

Apply Solder

Cool the joint

Cool the joint to room temperature to prevent failure of the joint prior to solidification of the solder.

Remove flux residue, if required

  -- Soldering Manual 2nd Edition, Revised, American Welding Society, 1978