Summer 2016 (Issue No. 31) Contents:

1. Eutectic Composition

2. Resistance Brazing

3. Plumbum - Regular Leaded

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A Eutectic Composition

Soldering and brazing alloys are commonly used in eutectic composition since doing so allows the bond to be made at low temperature compared to parent metals.  If you work with solders or brazes, it is important to understand properties of a eutectic and non-eutectic composition.  Please click on the link below to download a pdf document on this subject.

Eutectic Compositions (pdf)

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Resistance Brazing

Resistance brazing is a process that uses resistance welding equipment to produce a brazed joint.  Because of the uniqueness of the heating source that forces mating parts to be pressed against each other, the resistance brazing process has subtle differences compared to conventional brazing.  To read more about this topic, please click the following link and download a pdf document.

Resistance Brazing (pdf)

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Plumbum – Regular Leaded

Lead, which is the other half of the tin-lead system commonly used for soldering, gets its elemental symbol “Pb” from the latin word Plumbum; most likely due to its extensive use to make pipes and other connectors for transporting water in ancient Rome.  The word plumber is still in use today as someone who works on piping.  Lead is one of the first elements isolated in pure form almost 9000 years ago and found extensive use due to its malleability, low melting point, and high density.  Uses included sinkers for fishing, glazes, enamels, coins, and printing.  During the 20th century, Pb found even more uses including paints, gasoline additive, lead-acid batteries, solders, and additive to plastic insulation on electrical cords.

Lead is toxic to almost every part of the human body; much of it stems from the fact that the body confuses Pb ions with Ca ions.  Lead poisoning can happen by breathing dust, eating contaminated food, and skin contact.  While adults frequently get lead poisoning from industrial fumes and dust, children mostly get it through paints and toys.  Toxicity of lead has been recognized since a long time ago even during the Roman Empire when an engineer named Vitruvius advised against use of lead for drinking water pipes after observing illness of laborers working in lead foundries.  Many researchers attribute fall of roman the empire to cynicism, psychotic behavior, and dementia of emperors due to lead poisoning.  2000 years should have been a long enough time for us to eliminate lead from our lives; hopefully we will get there in the near future.

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