Aluminum Soft Solder Kit.

The service technician is frequently confronted with the task of repairing or joining aluminum to aluminum and aluminum to copper or brass.

A common repair problem occurs when an Air Conditioning System's evaporator coil develops a small pin hole leak.

Uniweld's P4KD9S is an excellent product for this repair due to it’s low melting point of 500 °F (260 °C) and 20,000 PSI tensile strength.

For best results, carefully read and follow the steps listed below:

(1.) Prepare the tubing by cleaning the surface and removing any oil, grease and oxides.

To remove the oil and grease, use a chemical solvent.

The oxides should be removed using only a stainless steel wire brush or emery cloth.

Tubing surfaces MUST BE CLEAN.

(2.) When making a repair on an evaporator coil, it will be necessary to preheat the tubing prior to applying the flux.

A common mistake when making this type of repair is to apply the flux and then begin heating the tubing.

The evaporator coil disperses the heat and the tubing never reaches the melting temperature of the alloy.

The flux overheats and burns which then acts as an inhibitor that doesn't allow the alloy to bond properly to the base metal.

Preheat the evaporator tubing and then apply the flux using the metal tip flux applicator.

(3.) Continue applying heat until the flux starts to bubble and then apply the solder into the area being repaired.

(4.) NOTE: If the solder is having difficulty flowing or the area has been overheated, “do not panic”.

Simply apply more flux using the metal tip flux applicator.

Reapplying the flux will clean the surface and allow the alloy to flow and bond with the base metal.

Allow the assembly to cool down slowly.

Remove flux residue with hot water and clean using only a stainless steel brush.