The chemical side of jewelry making

Various chemicals are used in the field of jewelry production.

Today, I will write about two of them, mainly the chemicals used for brazing.

For example, when making a ring, after bending the metal wire, make sure that the ends fit perfectly.

After the surface is filed, a type of welding called brazing is performed.

At that time, a chemical called flux is used so that welding can be performed neatly.

flux

Metals oxidize as long as they are in contact with air, forming an oxide film.

Since the oxide film interferes with the flow of the brazing material (metal for welding) during brazing, it is necessary to remove the oxide film to make the brazing material easier to flow.

When heated, flux has the effect of removing the oxide filed, it is applied.

Flux is a strong chemical whose main component is chloride, fluoride, boride, and borate.

Therefore, if flux remains on the brazed part, it may corrode from that part or change to a glassy type of material and interfere with polishing.

Therefore, it is necessary to soak the brazed metal in diluted sulfuric acid to sufficiently remove the flux.

Diluted sulfuric acid

Diluted sulfuric acid used to remove flux is a strongly acidic chemical, so care must be taken when using it.

If it splashes onto your clothes, you will get holes, if you touch your skin, your skin will be sore, and if you get it in your eyes, it will lead to blindness.

You must avoid accidentally immersing the hot metal after it has been heated to make it easier to handle or has just been brazed into diluted sulfuric acid instead of water because it is extremely dangerous.

Since the gas emitted by evaporation of diluted sulfuric acid is also harmful, it is necessary to ventilate well when using diluted sulfuric acid which has been warmed, and it is important to properly close the lid of the dilute sulfuric acid container after use.

And if the metal is soaked in dilute sulfuric acid for a long time, not only the flux but also the metal itself will dissolve in the diluted sulfuric acid, and the metal will be ragged.

In addition, the copper mixed to increase the strength of silver and gold dissolves in diluted sulfuric acid, which causes the copper to sulphurize and cause a chemical reaction, causing the transparent dilute sulfuric acid to gradually turn light blue.

The darker the light blue, the slower the reaction when the metal is put into diluted sulfuric acid to remove the oxide film, and it takes longer, so it is necessary to properly neutralize the dilute sulfuric acid before discarding it, and replace it with a new one. 

Even if you take the metal out from the diluted sulfuric acid in a short time and wash it with water and leave it as it is, diluted sulfuric acid will remain on the hand of the next person who touches it and if this person eats and drinks as it is, it will affect the person's health. Also, the acid erosion will progress and the metal will also be weakened. Therefore, it is very important to neutralize the oxidized metal by moistening the surface a little and scrubbing it with alkaline baking soda after soaking it in dilute sulfuric acid.

It's very diluted when making jewelry, but it's important to remember that it's still a dangerous chemical.

How was it?

At first glance, it is a glittering world of jewelry, but in reality, it is made using various chemical reactions and chemical property changes.

If you are interested, why not look up the chemistry used in jewelry making.