Regulatory issues: Difference between revisions

Most electronic solder has been made with the same formula since World War II (and before, in the case of some manufacturers like Kester). Scientists knew that a mixture of 63% tin and 37% lead was the eutectic mixture, meaning it had the lowest melting point. Since it's difficult to mass produce solder to such a close standard, most solder manufacturers simply get it as close as possible and call it 60/40 solder. The difference is not critical. Tin and lead are the least costly metals that can be used in a solder, and give very reliable results when used properly, so the 60/40 mixture became the standard for electronics manufacturing. Solders made of bismuth can have a lower melting point, but are more costly and can have problems with reliable wetting of a wire or [[PCB]] pad. Indium solders are excellent, but indium is extremely expensive. Solders carrying a high percentage of silver are also costly and are prone to oxidation. So the 60/40 tin/lead solder has been the most reliable, cost effective mixture for more than 90 years.

 

 

 

There are attempts being made by legislators in other countries to outlaw the RoHS substances. The US Congress has considered it, though with no action to date. The State of California will probably outlaw lead solder soon, with other states likely to follow.