No.2 Copper Wire (birch)

No.2 copper Shall consist of clean, untinned, uncoated, unalloyed copper wire and cable, not smaller than No. 16 B & S wire gauge, free of burnt wire which is brittle.

Hydraulically briquetted copper subject to agreement.

This is usually copper pipe that has a ‘new apparence look’ without any solder, paint or corrosion visible and no other forien material.

No.2 Copper Scrap Value

The usual commercial supplies of pure copper are used for the most critical of electrical applications such as the production of fine and superfine enamelled wires.

It is essential that purity is reproducibly maintained in order to ensure high conductivity, consistent annealability and freedom from breaks during rod production and subsequent wire drawing.

Since the applied enamel layers are thin but have to withstand voltage, they must have no surface flaws; consequently the basis copper wire must have an excellent surface quality.

Primary copper of the best grade is used for producing the rod for this work.

Uncontaminated recycled process scrap and other scrap that has been electrolytically refined back to grade ‘A’ quality may also be used.

The copper used for power cables is also drawn from high conductivity rod but to a thicker size than fine wires. The quality requirements are therefore slightly less stringent.

The presence of any undesirable impurities can cause problems such as hot shortness which gives expensive failures during casting and hot rolling.

For the same reason, scrap containing such impurities can only be used for this purpose if well diluted with good quality copper.

Where scrap copper is associated with other materials, for example after having been tinned or soldered, it will frequently be more economic to take advantage of such contamination than try to remove it by refining.

Many specifications for gunmetals and bronzes require the presence of both tin and lead so this type of scrap is ideal feedstock. Normally it is remelted and cast to ingot of certified analysis before use in a foundry.

Scrap of this type commands a lower price than uncontaminated copper.