We are pleased to announce that Online Metals is now carrying tin plated and silver flashed copper bars! These bars are copper alloy c110 H02 (Half Hard), with full-round edges and a thin covering of tin or silver flashing.

WHAT IS FLASHING?

Another term for “flashing” is weatherproofing. Simply, flashing is the process of plating a metal with something else. Usually, a different metal is used. This serves to protect the base metal from corrosion and oxidation. Consequently, aluminum, copper, galvanized steel, lead, silver, stainless steel, tin, and zinc are used for flashing. Historically, lead and even birch bark were two of the most popular materials used for flashing!

flashed copper

Tin flashed copper bar

WHAT IS FLASHED COPPER BAR USED FOR?

Tin and silver flashed copper bar is often used as busbar in circuit breakers, panel boards, and electrical switch gear.  Busbar is a highly electrically conductive bar. High current power is concentrated in the bar for distribution. Due to the large amounts of electricity running through these bars, they become very hot.

However, bare copper bar begins to oxidize at higher temperatures and copper oxide has poor electrical conductivity. Therefore, copper busbar is usually plated. The tin and silver flashing are more resistant to oxidation than bare copper. Hence, the flashed bars can reach higher temperatures without degrading and losing their conductivity.

Flashed copper busbar in an electrical substation, Bruchsal-Kändelweg.

Examples of flashed copper busbar at an electrical substation in Germany.

TIN OR SILVER?

You are probably asking yourself what are the virtues of the two types of metal used in flashing. Good question!

Silver flashing is normally seen as the superior flashing material due to the fact that silver conducts electricity as well as heat extremely well. Also, silver is more wear resistant and better for sliding contacts.

The main advantage that tin flashing holds over silver is that it is more cost effective. Even more, tin is more corrosion resistant in certain industrial environments that contain Hydrogen Sulfide. Specifically, silver begins to grow “whiskers” when exposed to Hydrogen Sulfide, whereas tin does not. Furthermore, these whiskers can cause electrical shorting, fires, and are extremely hazardous in general.

Silver Flashed Copper Bars Exposed to Hydrogen Sulfide.

This is bad. Don’t expose your silver flashing to Hydrogen Sulfide.

CHEMICAL AND MECHANICAL INFORMATION

Chemistry

Copper (Cu) – 99.9%
Oxygen (O) – .010-.050%

Mechanical InformatioN

Silver (Ag) Flashed

Tensile Strength – 38 KSI
Elongation – 18%
Hardness – HRF 80
Meets ASTM B187

flashed copper

Tin (Sn) Flashed

Tensile Strength – 40 KSI
Elongation – 18%
Hardness  – HRF 80
Meets ASTM B187

flashed copper