Electroforming Copper Feedhorns Using Aluminum Mandrels

Chemistry, Technology
[caption id="attachment_24084" align="alignright" width="480"] Copper electroforming bath, with growing electroforms and bagged anodes. Pump and continuous bath filtration are essential, though they are not shown for clarity.[/caption] The electroplating laboratory technician may be asked to grow a metal object from scratch, rather than merely plate an existing part. The result, before final external machining, is called an electroform. Electroforming involves much more than merely plating a long time. Critical issues need to be addressed to ensure success. While electroforming involves science, it is truly an art. Definitions and Basics [caption id="attachment_24085" align="alignleft" width="300"] A microwave feedhorn is similar to an old-fashioned ear trumpet. Image National Archives.[/caption] Microwaves are electromagnetic waves with a wavelength in the range of 0.001–0.3 meters. When creating a microwave feedhorn via electroforming, the scientist will grow…
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Fireworks Chemistry – Start With a Bang, Add Some Color

Chemistry, Entertainment
Pyrotechnics, often called fireworks, has a long history dating back to the days of gunpowder (black powder), developed in 9th-century China. Whether it is a sizzle, an explosion, or a showy display of colorful lights and sounds, the chemical reactions involve oxidation/reduction (REDOX) chemistry. What Is Oxidation? Oxidation is essentially the removal of electrons. Consider a very simple example. An uncharged sodium atom (symbol: Na) has 11 negatively-charged electrons. The atom has no net charge, however, because in its center part or nucleus, there are 11 positively-charged protons. Sodium can lose one electron to form a positively-charged ion called a cation. Now we can look at this process as if it were a mathematical equation. If we have the number 4 and we wind up with the numbers 3 and…
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Cuprous Sulfate: A Disagreement with My High School Chemistry Teacher

Chemistry, Education
[caption id="attachment_17698" align="alignright" width="440"] Classroom[/caption] As a kid, I was excessively shy and retiring – except when it came to matters of science and math. When it came to them, I was generally quiet but I could become quite outspoken if the occasion arose. During senior year, I approached my math instructor and told him an entire chapter in our textbook was wrong. He was reluctant to hear me out, but when he did, he acknowledged I was correct. On one occasion during junior year, I was listening to my chemistry teacher attentively when he spoke of cuprous sulfate. For those who are unacquainted with terminology, this would have been the old name (the name I still use) for copper(I) sulfate. I informed Mr. D’Alesandro that the only existing copper…
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Mummy Ötzi and the Bible

Bible, History
[caption id="attachment_13034" align="alignright" width="300"] A reconstruction of Ötzi's axe. Image by Bullenwächter, CC by 3.0.[/caption] Mummy Ötzi and Tubal-cain have what in common? Most scientists do not know. But it has to do with his axe. It also has to do with the Bible. The oldest and best-known naturally preserved mummy was discovered and uncovered in 1991. He had been frozen in ice for more than 5,000 years. Nicknamed Ötzi, a copper axe was found in his possession. What is so special about the axe? Scientists had previously believed metal objects would not be introduced for an additional 1,000 years. Mummy Ötzi Many new things were discovered in connection with mummy Ötzi. But the thing that should most interest sincere Bible students is the axe. Why? Because the Bible informs…
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Random Electroform Art – How It Can Be Created

The Arts
[caption id="attachment_14086" align="alignright" width="480"] Gold-plated dendritic copper electroform art.[/caption] Art takes many forms. As a chemist, I was assigned the task of forming high frequency electrical devices. I "grew" them from water based solutions of copper salts. I then electroplated them in gold baths. I'd found my kind of art - random electroform art! No one can say it is unoriginal. Preparation A form, or mandrel, was made of machined aluminum. A sodium zincate dip and rinse followed. Copper was grown over that. Not all areas received growth, though. Forms were masked to prevent growth in certain spots with a vinyl coating. This was applied by dipping and "painting." Growth After drying, the mandrel was inserted into the bath. Electricity was applied. Copper deposition began. After growth completion, the piece…
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Why Electroless Plating and Electroplating?

[caption id="attachment_6370" align="alignright" width="440"] Nickel Plating[/caption] Many items need require a coating of metal. Such can be applied in a couple of ways. One way is electroless plating. Another way is electroplating. Chrome handles on car doors are plastic with a veneer of metal. When you look in a mirror, you see your reflection in a sheet of glass with a metal film on the back. If you wear gold eyeglasses, there is a super thin coat of gold over base metal. Most plating uses a water solution containing metal salts. If an electric source is used to deposit the plate, the process is electroplating. If no electric source is used, it is auto-catalytic or electroless plating. How do these work? We will discuss the basics, beginning with electroplating. Electroplating…
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