Silver (jewelry)

Silver (jewelry) Known since ancient times: it is mentioned in Genesis . Debris deposits in Asia Minor and the Aegean islands indicate that man learned to separate it from lead around 3000 BC It represents 7.5×10-6% by weight of the earth’s crust.


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  • 1 Jewelry cleaning
    • 1 Soaps to clean it
    • 2 Liquids to clean it
    • 3 Paste to clean it
    • 4 Powders to clean it
    • 5 Stained Silver
    • 6 Cleaning trims, gallons and silver applications
    • 7 Cleaning the coins
    • 8 Cleaning silver items
    • 9 Cleaning silverware
    • 10 To clean German silver
    • 11 Cleaning the Silver with household products
    • 12 Quick cleaning
    • 13 How to prepare rags to clean the silver
    • 14 Carved silver
  • 2 Silver Alloys
    • 1 Silver and Copper Alloys
    • 2 Alloys for silversmiths
    • 3 Gui – shi – bu – ichi or Guishibuichi
    • 4 Silver-copper-nickel.
    • 5 Swiss divisional currency
    • 6 Chinese silver
    • 7 Japanese Silver (gray silver)
    • 8 Mousset Silver
    • 9 Ruoltz Silver
    • 10 Silver – tin
    • 11 Alloys for dentists
    • 12 Silver – Iron
    • 13 Silver – nickel
    • 14 Imitations of silver
    • 15 Silver – palladium
    • 16 Silver – lead
    • 17 Silver – zinc
    • 18 Silver substitutes
  • 3 Silver cleaning at the time of casting
  • 4 Formulas to skate the silver
  • 5 Skate at room temperature
  • 6 Silver patina with chlorine
  • 7 Antique or old jewelry
  • 8 Silver Solder Formulas
    • 1 Simple formula
  • 9 Otas Soldering Formulas
    • 1 How to weld jewelry with boric acid
    • 2 How to weld jewelry with boric acid
  • 10 Boric Acid
  • 11 Silver stain removal
  • 12 Analysis of Fine Silver – Pure
    • 1 Note
  • 13 Sources

Jewelry cleaning

  1. a) Silver objects attacked by sulfurous gases are cleaned by rubbing them with a borax solution and saturated and boiling. A solution of caustic potash with zinc chips also works very well.
  2. b) Ammonia carbonate 1 part, water 4 parts, plaster 16 parts; This mixture is applied with a dry cloth.
  3. c) Colcotar and prepared chalk, equal parts: this mixture is applied dry.
  4. d) Chalk 2 parts, zinc oxide 1 part, calcined deer horn 1 part.
  5. e) Acid baths composed of equal parts of sulfuric acid and water are also used, in which the silver objects previously heated to almost white red in a gas burner are kept for half an hour. Finally they are dried in boxwood sawdust. This procedure is only applicable to very solid and resistant silver objects.
  6. f) Add 40 drops of nitrobenzene, 50 parts of chalk, 10 parts of calcined deer horn and 10 parts of soap, in very fine powder, all very well mixed, to 40 parts of petroleum jelly.

Soaps to clean it

  1. a) to obtain delicatessen, dishes, etc. well scraped white or yellow soap 80 parts, calcined magnesia 18 parts, cover 2 parts, water enough. The soap is dissolved in the least amount of water possible, in the heat, and then the other ingredients are incorporated.
  2. b) white or yellow soap in fine scrapings 80 parts, Tripoli 8 parts, alum 4 parts, tartaric acid 4 parts, lead carbonate 4 parts, water sufficient quantity.
  3. c) well scraped white or yellow soap 100 parts, tin ash 4 parts, ammonia carbonate 8 parts, chalked chalk 16 parts. If you want you can color this soap with a pink pigment.

Liquids to clean it

  1. a) Vienna lime or prepared chalk 2 parts, ammonia 2 parts, water enough to make 8 parts.
  2. b) oxalic acid 1 part, saffron 2 parts, gypsum 4 parts, water enough to cook 15 parts. Shake before using this mixture, which if you want can be used dry (removing the water), or applied with a little oil, then rubbing the object with plaster.
  3. c) Creta prepared 240 gr, turpentine 60 gr, camphor alcohol 16 gr, ammonia 8 gr. It is applied with a sponge and once dry the object is rubbed with a soft cloth.
  4. d) Potassium cyanide 240 gr, alcohol 30 gr, ammonia 30 gr, copper sulfate 15 gr, sodium sulfate 30 gr, water 8 liters. You have the silver for a few minutes in this bath, then wash it with clear water, and polish it with a piece of suede or flannel.
  5. e) For jewelry and filigree objects. The objects are washed in a solution of 1 part of potash in 20 parts of water, rinse and have five minutes in a mixture of 1 part of salt, 1 part of alum, 2 parts of saltpeter and 4 parts of water; they are then washed in cold water and dried with a piece of suede .

Paste to clean it

A fine paste is made with levigated chalk (not precipitated) and sodium hyposulfite in equal parts, and a sufficient amount of distilled water; This paste is applied with a soft brush, then the object in question is washed with clear water and dried in sawdust. Some people prefer to let the paste dry on the object and then rub it and wash it with hot water.

Powders to clean it

Very fine chalk 15 parts, soda 1.5 parts, citric acid 0.5 parts. Everything is reduced to fine powder, which is applied with a little water.

Stained silver

  1. a) Very stained silver is cleaned by bathing it in a solution of 1 part of potassium cyanide in 8 parts of water (very poisonous). Afterwards, wash well with water and dry; to re-shine it is rubbed with suede and coat.
  2. b) If the silver is not very stained, rub it with a brush and a paste made up of 3 parts of purified and levigated chalk, 1 part of white soap and enough water.
  3. c) A very effective mixture is levigated chalk and ammonia solution, forming paste, but it has the drawback of giving a very bad smell and irritating the eyes a lot.
  4. d) How to remove ink stains from silver. Silver objects for domestic use, especially silver or silver inkwells, are often frequently stained with ink. These stains cannot be removed in the ordinary way, but with a paste of lime chloride and water. Soap water also works very well.
  5. e) How to remove egg stains from silver. The most intense egg spots are easily removed from the silver by rubbing them with your fingertip, after having covered them with a little common salt.

Silver Trim, Gallon & Trim Cleaning

A concentrated solution of soft soap and water is prepared, the decorations or objects in question are placed in it and the solution is boiled for a few minutes, five in general. The decorations are removed from this solution, the solution is placed in a basin, and as soon as it cools down enough to resist it by hand, the objects are well rubbed with a brush dipped in the solution. They are then washed with boiling water and placed on a porous body (a brick, or a piece of unglazed tile or tile) until dry. Finally they are carefully rubbed with a piece of suede, leaving the decorations as new.

Cleaning the coins

A 10 part sulfuric acid and 90 part water bath is made, and the coin is left in this bath until the silver sulfide crust dissolves. Ordinarily a five to ten minute immersion is sufficient, after which the coin is washed in running water, then rubbed with a loose brush or brush and Castile soap, washed again, dried with a rag and finished carefully rubbing it with a chamois.

Cleaning silver items

Pour the following mixture into a wide-mouthed jar: cream of tartar 2 parts, creta levigada 2 parts, alum 1 part. The alum is sprayed and mixed with the other two ingredients, after which the jar is tightly capped. When you have to use these powders, wet enough of them and rub the object with a thread plug, but without pressing too hard on it, because doing so can damage the silver layer, always very fine. It is then washed with hot soapy water and then with clear water, drying it with sawdust.

If the object is very blackened with silver sulfide, and it is small, it can be immersed for a moment in hydrochloric acid and immediately wash it in running water. Larger objects can be treated like coins, that is, immersing them for two to three minutes in a 10% aqueous solution of sulfuric acid, or quickly wetting their surface with a nitric acid-soaked pad, and immediately washing it with running water.

Silverware Cleaning

Silver or silverware is cleaned with any of the following compounds:

  1. a) Equal parts of precipitated ferric subcarbonate and prepared chalk.
  2. b) Calcined ferric oxalate.
  3. c) Mercury and lime in equal parts 15 gr, prepared chalk 60gr. When using this mixture, add a little alcohol and rub it with chamois. Its result is not always satisfactory.
  4. d) Iron sulfate is poured into a large tobacco pipe, and it is put on the fire for a quarter of an hour, after which it is mixed with a little powdered chalk. It is used dry.
  5. e) Add 240 g of finely powdered chalk, little by little, to a mixture of 60 g of camphor alcohol and 8 g of ammonia; apply this mixture with a sponge and wait for it to dry before rubbing the silver to polish it.
  6. f) Fine chalk 30gr, cream of tartar 60 grams, Tripoli 30 gr, almagre 30 gr, alum 20 gr, alum 20 gr, everything is pulverized in a mortar. This mixture is applied moistened, rubbed on the silver, and when it dries, rub with a dry flannel, or clean with a brush.
  7. g) When the silver is to be stored for a long time, it prevents blackening by giving it a thin layer of collodion.
  8. h) Mix 1 part of colcotar with 12 parts of magnesia carbonate.
  9. i) Powdered tin ashes 2 parts, chalked chalk 10 parts.
  10. j) Equal parts of common salt, alum and cream of tartar; everything is dissolved in hot water and boiled with the dishes inside.
  11. k) To clean commonly used silverware or silverware, slightly blackened from being stored, they are covered with a layer of white from Spain melted in water, which is applied with a brush. They are left to dry in the sun for a few hours and finally the layer is separated with a brush or suede.

To clean German silver

In addition to the general formulas for cleaning silver and other metals, levitated pure iron peroxide, mixed with a little oil, is used with great results. If the object is very dirty, rub this mixture with your finger, and if it is only slightly dark, rub it with a piece of suede and a little dry iron peroxide; then remove the powders with a brush or fine brush.

Cleaning the Silver with household products

The following methods can be used to clean silver objects: Make a mixture with alcohol, clean materials and water, in equal parts; Bismuth oxychloride dissolved in alcohol is another very effective formula. In both cases, a creamy liquid should remain, with which the silver objects will be rubbed and polished.

Silver objects can also be cleaned with the water used to boil potatoes or spinach. It is especially suitable for brightening objects that do not have many stains.

On the contrary, if they are very dirty, soak them in a solution of ammonia and hot water, in equal parts, let them rest for a few minutes, and then dry them well with a cloth and rub them to make them shine.

Another very effective formula consists of: a tablespoon of alcohol vinegar, a handful of coarse salt, a splash of dishwasher detergent and a liter of hot water. The parts to be cleaned are immersed in this product for fifteen minutes and then rinsed with soapy water.

Cutlery: if they are excessively dull when removed from the case, a good remedy is to boil them in a saucepan with hot water. Dirt will rise to the surface and the cutlery will be clean and shiny.

To prevent scratches from silverware, they should be kept in a case containing soft fleece. They should not be placed in a dishwasher, unless they are protected by a special varnish.

Candlesticks: If they have traces of wax, you should never try to remove them with your fingernails, the only thing that will achieve is scratch them. Bring two pans of water to a boil and dip it, first in one of them to remove dirt and then in the other to make it shiny. Dry with a cloth and polish with a cloth.

Quick clean

How to clean the silver: immerse the objects in a container with a little soda and several pieces of aluminum foil ; add water to cover them all (dust and dirt will settle on the aluminum), then cover them with hot water and dry them. Then clean them with a cloth soaked in a specific long-lasting protector.

Quick cleaning: to quickly shine, put a few drops of turpentine on a piece of cotton and float the objects with it. Then rinse very well.

Another option: put one part of soda for every 20 of water and pour the mixture into an aluminum saucepan. Dip and remove the silver in the solution, then rinse it in hot water and dry it.

How to prepare rags to clean silver

Make a solution of 10 parts cold water, 2 parts ammonia for home use, and one part of a long-lasting silver polish. Cut several pieces of cotton and soak them in the mixture, then let them dry. This system is ideal for cleaning jewelry and cutlery.

Do not use homemade product on silver objects that have stones; the crimp could be loosened. If you use and wash silver regularly, you don’t need to polish it often.

Small scratches: removed with iron oxide. Never wrap silver objects in plastic as the condensation could tarnish it, do it on newspaper, especially when you are going to store it for a long time.

Carved silver

When cleaning silver objects with a chemical, take care not to leave residues of it on the silver, it will tarnish more quickly. Always clean it near an open window, since cleaning silver gives off sulphurous gases that are very harmful to health. To clean carved silver pieces use special brushes that are sold only for silver cleaning and use only for this. Never use a toothbrush or a brush. It could scratch the surface.

For plating, use a special brush that you can get at a jewelry store, or a children’s toothbrush to get to the gaps in large objects. To clean deep grooves, wrap the end of a toothpick in cotton, soak it in a silver cleaning liquid and run it through all the nooks, then rinse thoroughly with clean water.

Silver alloys

Silver and Copper Alloys

When silver is alloyed with copper, only a ratio is known that of a homogeneous foundry, which is 72% of silver to 28% of copper. With more than 72 percent silver, the center part of a cast bar is richer than the edges, which harden sooner; on the other hand, with a percentage of silver less than 72, the axis of the bar is poorer and the sides richer. This characteristic property of silver and copper alloys is known to metallurgists as “segregation”.

The bleaching of silver and copper alloys is best achieved by tempering the alloy until the surface begins to turn black. The alloy is quenched in a mixture of 20 parts, by weight, of concentrated sulfuric acid and 1000 of distilled water, leaving it immersed in this mixture for some time. Instead of sulfuric acid, potassium bisulfate can be used, in the proportion of 40 parts per 1000 of liquids. If necessary, the tempering process is repeated.

Alloys for silversmiths

  1. a) Silver 77 parts, copper 6 parts. b) Silver 40 parts, copper 3 parts. c) Silver 4 parts, copper 1 part. d) For chains: silver 3 parts, copper 2 parts.

Gui – shi – bu – ichi or Guishibuichi


It is the name of the material with which certain glasses, containers, etc. are manufactured, coming from Japan; It consists of an alloy with 50-70 percent copper and 50-30 percent silver; This alloy is then colored in gray-green by treatment with a special mordant. Embedding the metal with materials not attackable by the mordant (for example, noble metals) produces especially beautiful effects. The Gui-shi-bu-ichi or Guishibuichi is analogous to Shakudo.


When nickel is added to silver and copper, several good alloys result, such as the following, made in France:

Metals TO B C
Silver 33 40 twenty
Copper 37-42 30-40 45-55
Nickel 25-30 20-30 25-35

Swiss divisional currency


These alloys, by the metals that go into their composition, can be defined as silver or German silver, with a certain proportion of silver; They have been used to make small coins, as was done before in Switzerland. As these alloys are quite hard, they have the advantage of wearing very little, but instead lose their Argentine whiteness very soon and take on an unpleasant-looking yellowish tint, similar to that of poor bronze. The silver contained in these alloys can only be recovered by a very laborious process, which constitutes a great disadvantage for its use in minting coins. The composition of Swiss fractional coins is as follows:

Metals 20 cent 10 cent 5 cent
Silver fifteen 10 5
Copper fifty 55 60
Nickel 25 25 25
Zinc 10 10 10

Chinese silver

  • Copper 65.24 per 100,
  • Tin 19.52 per 100,
  • Nickel 13 per 100,
  • Silver 2.05 percent.

Japanese silver (gray silver)

In Japan they prepare an alloy made up of equal parts copper and silver, and they take a nice gray color by boiling in an alum solution to which copper sulfate and verdigris are added. The alloy called Mokum or Mokume Gane, also Japanese, is prepared by placing, on top of each other, thin laminates (foil or loaves) of gold, silver, copper and the alloy that we have just indicated, joining them with hammer blows; the cross sections of the thin plates that result are presented in the colors of the different metals from which they are formed, which gives them a nice striped appearance. the “Mokume Gane or Mokum” is used mainly for ornaments on articles of gold silver .

Mousset Silver

  1. a) Copper 59.06 parts, silver 27.56 parts, zinc 9.57 parts, nickel 3.42 parts. This alloy is yellowish with a reddish tint, but white fracture. It takes the immediate place of Ruoltz silver, which also sometimes contains a certain amount of zinc, and which in this case can be classified together with the alloys we are working with.

The following alloys can be cut into sheets or stretched into wires: b) Silver 33.3 parts, copper 41.8 parts, nickel 8.6 parts, zinc 16.3 parts. c) Silver 34 parts, copper 42 parts, nickel 8 parts, zinc 16 parts. d) Silver 40 parts, copper 44.6 parts, nickel 4.6 parts, zinc 10.8 parts.

Ruoltz Silver

It is made up of 20 parts of silver, 50 of copper and 30 of nickel. These proportions may undergo some variation.

Silver – tin

A very small amount of tin makes silver very brittle. According to Guettier, these alloys are hard, sour and brittle. The one that contains 80 percent tin has a hardness equal to that of bronze: that of 52 percent tin is somewhat malleable. All these alloys are easily oxidized, and their specific weight is less than the average of the component metals. Tin can be separated from silver by fusion with corrosive sublimate, leaving the silver pure.

Dentist alloys

  1. a) Dentists use an alloy of 60 parts pure silver and 40 parts tin, with some mercury, for fillings. b) Tin 91.63 parts, silver 3.82 parts, copper 4.4 parts. c) Tin 36.78 parts, silver 48.32 parts, copper 14.72 parts.

Silver – Iron

These two metals are not alloyed. Stoddard and Faraday have experimented with silver and steel, concluding that the best alloy is that obtained with 1 part steel and 300 parts silver. These alloys are of no practical interest.

Silver – nickel

Berthier silver. Berthier describes an alloy of these two metals, with 13.5 percent nickel , white, capable of acquiring a good polish and that can be rolled very well. The alloys of these two metals have so far been little studied.

Imitations of silver

  1. a) Silver 480 parts, nickel 491 parts, copper 969 parts. b) Silver 180 parts, nickel 93 parts, copper 181 parts, zinc 30 parts.

Silver – palladium

This alloy, made up of 9 parts palladium and 1 silver, is used almost exclusively by dentists, serving very well to make false teeth, as it is stainless. Another alloy, used even more than the previous one, consists of 10 parts platinum, 8 palladium and 6 gold.

Silver – lead

These alloys have application in industry. Silver and lead come together easily in all proportions. Very little lead is sufficient to decrease the malleability and ductility of silver. Molten lead dissolves silver, like mercury, the mixture being homogeneous only for as long as it remains liquid.

Silver – zinc

Silver and zinc have a great affinity for each other, which is why their alloys are easily made. The necessary amount of zinc, wrapped in paper, is poured into the molten and very hot silver, stirring the dough very well with an iron rod and pouring it immediately with the molds. Silver and zinc alloys can be made to be both flexible and ductile. An alloy composed of 2 parts zinc and 1 silver looks silver for its color and is quite ductile; with a higher proportion of zinc, the alloy is brittle. When preparing the alloy, it is necessary to use a somewhat greater quantity of zinc than it must contain when fining, since a small amount of this metal always volatilizes.

The 80% silver Berthier alloy can spread on very thin sheets and is stiff, tough and elastic. The Godfrey alloy is prepared by pouring molten zinc over molten silver in these proportions:

Metals TO B C D
Silver 8.16 22.47 49.72 67.58
Zinc 91.84 77.53 50.28 32.42

Alloy (a) is bluish-gray, hard, brittle, and scratched with a razor; the fracture is bluish gray, finely grained, not very bright.

(B) is bluish-gray surface color; harder than the previous one, fragile, and scratches less easily; its fracture is bluish gray, shiny and fibrous.

(C) is copper-red on the surface, after solidification; it is hard, brittle, and friable; his cold fracture is white, shiny, and somewhat stringy.

(D) has a reddish yellow surface color; it is hard, fragile, with a white fracture, very bright and quickly miscible; its structure is fibrous.

The 2 part zinc and 1 part silver alloy is very ductile, finely granular and almost as white as silver.

Silver and zinc alloys have been tested for minting. Piligot prepared alloys with 5.0, 10 and 20 percent zinc respectively, which were white, with a slight yellow tint, resulting in elastic and voiced coins. These alloys do not blacken as easily as those of silver and copper due to the effect of hydrogen sulphide.

Silver substitutes

  1. a) Iron 65 parts, tungsten 4 parts; they melt together and granulate. In a separate crucible melt: 23 parts nickel, 5 parts aluminum and 5 parts copper, adding a piece of sodium to prevent oxidation. These two granulated alloys are then melted together. The alloy obtained resists the action of the sulfurized hydrogen.
  2. b) Copper 75 parts, zinc 7 parts, nickel 16.5 parts, iron 1.25 parts, cobalt (oxide) 1.75 parts, tin2.5 parts. Zinc is first melted with 12 parts copper; then nickel with the same weight of the zinc alloy, in a graphite crucible, and finally iron with the rest of copper and cobalt, mixed with coal. The mass is covered with charcoal and subjected to an elevated temperature; once the mass is melted, and maintaining the same temperature a little longer, the rest of the copper-zinc alloy is added, the temperature being sufficient to melt the latter. The crucible is removed from the heat and stirred with a hazelnut rod, and then the tin is added in pieces wrapped in thick paper, the total mixture is shaken a little and poured into the molds. This alloy is cold worked like silver, with which it has great similarity in its properties. Zinc almost completely volatilizes during melting.
  3. c) Sterlin metal. It is a white metal much like silver, containing 68.52 percent copper, 12.84 percent zinc, 17.88 percent nickel, 0.76 percent iron, and traces of lead. Silver and manganese have not been found in any analysis; however, a little of this metal should be added to facilitate the incorporation of iron. According to Sperry, if an alloy of 4 parts iron and 1 part 1 part manganese is melted with copper and nickel, iron is incorporated into the latter, resulting in a perfectly homogeneous compound, proving that manganese disappears completely after a or four fissions of the alloy.

Next we insert a table with the composition of the main alloys that give good white metals to replace silver in many of its applications.

Silver cleaning at the time of casting

  • Introduction:

Silver Foundry

This procedure allows silver to be cleaned of oxides and allowed to come out clean and bright in color after casting into the crucible.

  • Materials:
  • Baking soda
  • Boric acid
  • Saltpeter
  • Process:

In the crucible where the silver is going to melt, smear the walls of the same with bicarbonate since this will cause all the material to peel off and detach from the walls. To spread the walls of the crucible with bicarbonate, it is in the form of powder, that is to say, passing it with a dry sponge or with your hands.

Then at the time of melting the silver when this liquid is made with bicarbonate and boric acid in amounts of 2 grams for 3 times in intervals, later the same is done with the saltpeter but in a smaller amount 1 gram for 3 times, this will achieve that the Material comes out clean and brightly colored.

The proportions of bicarbonate and boric acid are in equal parts (2 grams by 2 grams) simultaneously at intervals of 3 times per melt.

Silver skating formulas

The process of giving color (oxidation) to silver is called patina. The potassium sulphate (known as liver of sulfur) is used to skate old color (black) silver.

This solution is bought mainly in old apothecaries and they know it like Sulfur Liver .

Process: 1g of Potassium Sulfate is dissolved in 400 ml of water and heated in a pewter container (lined with porcelain), not allowing the solution to boil since the vapors become toxic. The jewelry is immersed using a plastic strainer, and left until it acquires a uniform black color.

Subsequently, it is rinsed in running water, dried and polished with a blanket and paste to remove excess patina, thus leaving the bas-reliefs of the jewelry design dark and old-looking.

Store the Potassium Sulfate stone in a tightly closed plastic bag and place it inside an amber glass container which should be stored in the dark and in a cool place. Light and heat decomposes Potassium Sulfate.

It is very important that patinated or oxidized jewelry in this way is not cleaned with liquid jewelry cleaning solutions as the patina will be removed resulting in a grayish finish to the jewelry. If the piece of jewelry turns slightly yellow it can be polished with a flannel impregnated with a little commercial polishing paste.

Skate at room temperature

A formula that can be used to apply patina at room temperature without having to heat the solution is:

Water = 3.8 Lt Ammonia = 8 ml Sulfur Liver = 56 g

Water = 200 ml Ammonia = 0.3 ml Sulfur Liver = 2.5 g This solution can be applied with a brush or brush at room temperature.

Silver patina with chlorine

Another way to oxidize or patina silver jewelry (in addition to the one described with sulfur liver) to give it this old-fashioned look is by using chlorine (commercial bleach solutions used to rinse clothes can be used, eg. ” Chloralex “).

Process: jewelery is immersed in a plastic container containing chlorine at room temperature and approx. 20 minutes. During this time the piece will acquire a black color.

Subsequently, the jewelry is removed from the chlorine, rinsed with water and polished with a blanket to remove excess oxidation and thus give the jewelry an ancient enhancement, and its textures will stand out much more.

Antique or old jewelry

One way to skate or make silver old is as follows:

Mix 2 teaspoons of Sulfur Flower (powder) in a cup of water and add 2 drips of liquid soap to clean junk. Subsequently, the piece of silver jewelry that you want to make old is heated and immersed in the previous solution. This operation is repeated until the desired shade is obtained. The resulting jewelry will have a completely dark finish. To finish, the silver jewelry is polished to remove excess patina and thus only leave the old finish inside the textures.

Note: The function of soap is to help powdered sulfur to disperse in water, since water and sulfur do not naturally mix.

Silver Solder Formulas

In the Silver solder, the amount of Zinc that is present is what will determine the melting point of the solder, (Ag = Silver; Cu = Copper Cd = Cadmium and Zn = Zinc).

The different types of silver solder are: Extra Hard: 80% Ag + 16% Cu + 4% Zn (Melting point at 809 ºC)

Hard: 76% Ag + 21% Cu + 3% Zn (Melting point at 773 ºC)

Medium: 70% Ag + 20% Cu + 10% Zn (Melting point at 747 ºC)

Soft: 60% Ag 25% Cu 15% Zn (Melting point at 711 ºC)

Extra Soft: 50% Ag + 15% Cu + 15% Zn + 20% Cd (Melting point at 681 ºC)

Simple formula

Silver solder can be made by mixing .925 Silver with 50% Brass. For example: to 10 g of Silver .925 5 g of Brass are added; giving a total of 15 g of Silver Solder with a medium melting point.

Note: An easy way to make Silver Solder with different melting points is to mix only Copper, Silver and Brass in the following proportions: Brass and Fine Silver. (Brass = 65% Copper + 35% Zinc). The melting point of Zinc is 419 ºC and vaporizes at 907 ºC. Hard Solder: 19g Ag + 3g Brass + 3g Cu Medium Solder: 17.5g Ag + 7.2g Brass + 0.3g Cu Smooth Solder: 15g Ag + 10.8 g Brass After melting the metals, it is recommended to laminate to gauge No. 27

Otas Formulas for welding

  • Introduction:

How to easily prepare a silver solder for silver jewelry.

  • Materials:

Pineapple silver (fine or pure silver) – 10 g Bronze – 4 g Borax Melting pot

  • Processing:

Laminate the bronze to the thickness 0.20 mm thick cut into pieces, then place the pure silver in the crucible and gradually melt the silver with the bronze, after melting it, laminate it to the desired thickness and you will have a good weld. How to Prevent Fire Stain in Jewelry Example of fire stain on silver foil. The stain is reddish or brownish in color.

How to solder jewelry with boric acid

Many times when silver jewelry is manufactured, when polishing the pieces, a dark stain or film comes out on its surface, which prevents the jewelry from having a shiny finish.

This dark stain is called “Fire Spot” and is caused by the oxidation of the copper present in silver jewelry when excess heat is used (and without using a reducing flame on the torch) when annealing or soldering the parts. of jewelry.

(Silver jewelry has a ratio of 7.5% copper to give the Sterling or .925 alloy.)

One way to prevent this stain from appearing is to cover the surface of the piece with a mixture of boric acid and alcohol .

The piece is immersed in this solution, then it is dried using the torch fire, which causes the alcohol to ignite and evaporate leaving a uniform white coating on the surface of the jewel.

Subsequently, the flux is applied to the area to be soldered.

This mixture of Boric Acid and Alcohol is also used to cover gold jewelry when it is to be welded or repaired to prevent the fire from affecting the finish or shine of the piece.

How to solder jewelry with boric acid

It is important to stir the mixture of boric acid and alcohol before immersing the piece of jewelry or if you are going to apply this solution with a brush to resuspend the boric acid that tends to rush to the bottom of the container.

Likewise, the vapors of the Boric Acid and Alcohol mixture should not be inhaled when lit with fire, as it is harmful to health.

Boric acid

Boric acid is a chemical compound that contains boron, hydrogen, and oxygen . It is a weak acid. It exists in the form of colorless crystals or white powder and is soluble in water.

Boric acid is a commercially important borate frequently used as an antiseptic, insecticide, flame retardant, and food preservative. It is also used in adhesives, detergents, in the manufacture of glass and paper , and to reduce the melting point of welds.

Silver stain removal

Many times when silver jewelry is manufactured, when polishing the pieces, a dark stain or film comes out on its surface, which prevents the jewelry from having a shiny finish.

This dark spot is called “Fire Spot” and is caused by the oxidation of the copper present in silver jewelry when excess heat is used when soldering the parts of the jewelry.

(Silver jewelry has a ratio of 7.5% copper to give the Sterling or .925 alloy.)

One way to remove this dark stain is by using Nitric Acid. Prepare a 50% solution of nitric acid in water (see note below) and place it in a hard plastic container. Subsequently, the finished jewelry will be immersed in the acid (before the polishing process) using a plastic strainer.

It is very important that this process is worked outdoors since toxic gases will be produced during the preparation of the acid and the immersion of the jewelry in it. Also avoid contact with the skin as it causes burns.

The immersion time of the jewelry in the acid is approximately 10 to 20 seconds. During this time, the acid will attack the jewelry, dissolving the fire stain and also part of the metal of the piece. Therefore, it is very important to be careful not to leave the jewelry in the acid for long.

At the end of the acid immersion time, the jewelry will have a gray-looking film on its surface. The jewelery is immersed in a solution of sodium bicarbonate saturated in water (see note) to neutralize the action of the acid and later it is rinsed in running water.

Finally, jewelry is polished using cotton blankets and bristle brushes impregnated with polishing paste.

As the 50% nitric acid solution is used, it becomes saturated with copper and its color becomes light blue, so its power to eliminate the fire stain becomes less.

Fine Silver Analysis – Pure

Do you know how to identify the purity of silver? How to know if the pure silver they sell us to make castings or sheets is really pure.

To know if silver is pure, the following analysis of fine, pure silver can be made:

Two small glass jars are added to each 10 milliliters of 50% nitric acid in water, and identified with a label, (+ see note +)

Subsequently, to the bottle number -2- 2 grams of pure silver are added and to the bottle number -1- 2 grams of silver are added, of which one wishes to know its purity (in this case Sterling silver .925 was used) .

Bottle number -2- is our reference or control test and bottle -1- is the experimental test. Both bottles are placed in the open air since the reaction with the acid will produce toxic vapors.

The acid and silver inside the bottles are left to stand for 45 minutes, or until the silver is completely dissolved in both bottles and the changes in the solutions are then observed and noted.

a – Pure silver does not react as vigorously – bubble production – with nitric acid as silver mixed with copper does.

b – The pure silver in the solution with the acid, does not give a change of coloration during the 45 minutes of reaction, remaining practically transparent. however, silver mixed with copper – .925 – will result in a light blue solution.

c – The pure silver in the solution with the acid does not change its color when a trickle (approx. 4 ml) of pure ammonia is added. However, a silver mixed with copper -.925- will result in a deep blue coloration when reacting with ammonia.

Therefore, if bottle -1- containing the experimental silver sample does not change color during the reaction with nitric acid during the 45 minutes of interaction, and also when ammonia is added, we can conclude that the silver is not found combined with copper or some other metal.

The described test is qualitative. if an accurate silver composition result is desired, the sample must be taken to a specialized metal analysis laboratory.


Preparation of the acid solution is dangerous. Always add the water to the container first and then very carefully add the acid. To know the precautions that must be taken when preparing an acid solution.


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