Hard Soldering Glossary

Talk the talk with these three charts all about the hard soldering jewelry-making technique. First learn about the materials used, then the necessary tools and finally a list of helpful terms.

Soldering Materials	Description
Acetylene	A gas used with torches. Acetylene can be used with ambient air, oxygen or compressed air. An acetylene/ambient air combination reaches 3270 degrees Fahrenheit. An acetylene/oxygen combination produces a flame up to 5080 degrees Fahrenheit. An acetylene/compressed air combination reaches 3848 degrees Fahrenheit. This is not a clean burning fuel, so you may find that deposits of blackened carbon are left behind.
Anti-Flux	This is quite literally the opposite of flux. Anti-flux is a material that is applied to deliberately dirty a specific area of the metal being soldered. This application keeps solder from flowing to the coated area. Almost anything that is non-flammable and will adhere to your metal can be used as an anti-flux.
Binding Wire	Used to hold pieces to be soldered. Binding wire is also wrapped around charcoal blocks to prevent cracking. Use 304 type stainless steel or iron wire in a dead soft temper--this is soft enough to easily manipulate yet can still stand the temperatures used in hard soldering.
Butane	The primary fuel used with micro torches.
Flux	A solution that keeps metal clean, allowing the solder to flow properly. The application of flux also prevents the buildup of oxidation, reducing the chance of firescale and cleanup time. Flux should be applied to both your metal pieces and your solder to ensure no contamination. Flux is available in liquid and paste forms and can be brushed or sprayed onto your pieces. Flux is not usually needed when working with syringe forms of solder, as it has already been added.
Natural Gas	A readily available fuel option for torches. Natural gas can be used in tanks with a regulator. Many cities provide natural gas through municipal lines as another supply option; a regulator isn't usually needed in this case. Check for local regulations and hook-up procedures to ensure safety when using a direct gas line. A natural gas/oxygen combination produces a flame up to 5120 degrees Fahrenheit. A natural gas/compressed air combination reaches 3,565 degrees Fahrenheit. Unlike acetylene, natural gas burns clean and does not leave stains from blackened carbon.
Oxygen	This is not the "oxygen" that you are currently breathing (which is actually made up of over 10 different gasses, including oxygen). This is pure oxygen that is presented in a pressurized tank. Oxygen is not a fuel, but is used with acetylene and propane in dual tank systems to create hotter flames. As the tank is under pressure a regulator must always be used.
Pickle	A solution that removes oxides from metal pieces after soldering. Pickle solution works best when warm, but should not be boiling.
Propane	This fuel may also be known as LPG (liquefied petroleum gas). Propane can be readily found at hardware and general stores in many areas. In most cases this is a less expensive fuel option for soldering. This fuel can be used with ambient air or with oxygen.
Solder	A metal alloy that is specifically formulated to have a lower melting point than precious metals. This is used to join pieces of metal together. Solder is available in wire, sheet and paste forms. There are different grades of solder; each has a different flow point.

Soldering Tools	Description
Charcoal Block	Used as a surface for soldering projects. Charcoal blocks create a reducing atmosphere when heated, reflecting the heat back to your project. This shortens the amount of time needed to reach the flow point--fighting firescale. This type of work surface has a shorter lifespan than firing blocks. Be sure to wrap your charcoal block with binding wire to keep cracks away.
Cylinder	Another term for a gas tank.
Electronic Torch Igniter	A replacement for the traditional striker for lighting a torch. This tool allows your torch to be ignited using only one hand and no squeezing. The filament in place of the traditional flint provides thousands of strikes. Batteries are required.
Firing Block	Also known as a fire brick. Used as a surface for soldering projects. Fire bricks are a flame-resistant compressed ceramic that reflects heat back to your piece. This shortens the amount of time needed to reach the flow point, reducing the chance for firescale.
Fire Extinguisher	This is a safety must in any soldering studio. A fire extinguisher should be on hand, and in good condition, at all times. Be sure to have an extinguisher that can be used on class A and class B fires; as you will have ordinary combustibles and flammable gases in your studio.
Flashback Arrestor	May also be called reverse flow check valve. An absolute must for torch users. This is a device that stops any reverse flow of gas into your tank or supply line, preventing flame from traveling back to the fuel supply. This is needed to prevent damage to your equipment and yourself. In some areas flashback arrestors are required by law. Some styles also ensure that gas flow is shut down in both directions once pressure drops to a certain level--providing additional protection when the equipment is not in use.
Honeycomb	A soldering board that has a honeycomb design. Pins can be inserted into the honeycomb to help keep pieces in place during soldering. These are available in a number of soldering board materials.
Micro Torch	A small hand-held torch that generally uses butane for fuel and has built-in electric ignition. Depending on the style selected, fuel is injected into the torch canister, or a canister of butane is inserted directly into the torch. These are great torches when starting, or for someone "trying out" soldering. Since these are smaller than tank torches in both flame size and maximum temperature, there is a limit to the size and type of project that can be handled.
Pick	A tool used to place and move solder and metal pieces during soldering. Picks made for soldering are tungsten or titanium, as solder won't melt onto these materials.
Regulator	Regulators are used with torches--your hose should never be connected directly to your fuel or oxygen tank. Regulators control the flow of gas and lower the pressure as the gas moves from the tank to the hose. Be sure that you are using the correct regulator; for example, propane tanks will have a different regulator than acetylene tanks.
Reverse Flow Check Valve	Also called flashback arrestor. An absolute must for all torch users. This is a device that stops any reverse flow of gas into your tank or supply line, preventing flame from traveling back to the fuel supply. This is needed to prevent damage to your equipment and yourself. In some areas reverse flow check valves are required by law. Some styles also ensure that gas flow is shut down in both directions once pressure drops to a certain level--providing additional protection when the equipment is not in use.
Safety Glasses	A safety must for soldering--there are lots of small metal parts, molten solder and flame. Keep them in your studio and use them every time!
Screen	A steel mesh that that is placed on a tripod to allow all angle torch access to the project.
Soldering Board	A board that is heat resistant and used as a work surface during soldering. Soldering boards come in a number of materials; some absorb heat to slow the soldering process and others reflect heat to speed it up.
Soldering Iron	A tool used in soft soldering techniques, such as tinning and electronic connections. Soldering irons require electricity, not gases, to create heat. Soldering irons cannot achieve the temperatures required for hard soldering techniques.
Striker	Used to light a torch by quickly squeezing the handle. The friction on the flint creates a spark. Flint will need to be replaced periodically.
Tank Key	Also known as a tank wrench. This tool comes with new gas tanks; replacements can be purchased separately if you lose yours. Be sure to use this with your tank and hose fittings, as a wrench or pair of pliers can round out the edges of fittings.
Torch	Provides the high heat needed for hard soldering through flame. Torches use fuel, fuel/oxygen combinations, or fuel/air combinations. In most cases these have one to two tanks that are connected to a torch tip by hoses.
Third Hand	A tool that holds pieces in place while your hands are busy with other things, such as holding a pick and a torch. Third hands come with one or more locking-style tweezers. Be sure that the base of your third hand is heatproof.
Copper and Bamboo Gripping Tools	Tongs are used to move your newly soldered piece into and out of a pickling solution for quenching. When soldering, be sure to use only copper tongs or bamboo tweezers when quenching in pickle. Your steel (and other ferrous metal) tweezers will cause a reaction in the pickling solution; the result is contaminated pickle and metal that is difficult to clean.
Torch Tip	Torch tips are connected to the end of the hose on your torch system. The tip you use determines the size of the flame produced. Tips are numbered for size; the smaller the number the smaller the flame. Micro torches will not generally have the ability to change out tips.
Tripod	A three legged stand that can be used in place of a soldering board. A tripod is used with a screen to allow heat application on all sides of a project.
Tweezers	Tweezers are used to move and hold metal pieces and solder. Prior to firing up the torch, you may find non-locking tweezers the best choice; control is easier when picking up tiny pieces. When soldering use cross-locking tweezers; they don't require a squeezing action to stay closed. Also make sure that your cross-locking tweezers have a fiber grip to provide additional protection from hot metal for your fingers.

Soldering Terms and Techniques	Description
Applique	Also called overlay. A technique in which a metal piece is soldered to the top of a larger metal piece.
Ball	This is what solder does as it reaches the melting point. This indicates that the metal and solder are reaching the flow point.
Butt Join	A soldering technique that joins two pieces of metal end to end. This is the most common join used in jewelry soldering and can be used with both flat and curved pieces.
Cupric Oxide	A reddish oxide that forms on sterling silver when it is heated. In most cases this can be removed by immersing the object in warm pickle.
Cuprous Oxide	More commonly known as firescale. A stain that appears on your metal due to exposure to heat. Unlike cupric oxide this is more difficult to remove; the oxidation actually goes deep into the metal instead of just being on the surface. Most cuprous oxide can be removed by sanding until all the discoloration is gone; however, this may have an effect on the finished piece. Cuprous oxide appears as a dark purplesque color when working with sterling silver. When soldering brass or bronze the stain will appear copper. Cuprous oxide can be prevented, or at least held to a minimum, by using flux and limiting the heat exposure of the metal as much as possible.
Ferrous	A material that contains iron. Generally used in reference to metal.
Firescale	Scientifically known as cuprous oxide. A stain that appears on your metal due to exposure to heat. Unlike cupric oxide this is more difficult to remove; the oxidation actually goes deep into the metal instead of just being on the surface. Most cuprous oxide can be removed by sanding until all the discoloration is gone; however, this may have an effect on the finished piece. Fire scale appears as a dark purplesque color when working with sterling silver. When soldering brass or bronze the stain will appear copper. Fire scale can be prevented, or at least held to a minimum, by using flux and limiting the heat exposure of the metal as much as possible.
Flow Point	The temperature at which solder follows a join. This temperature is usually about 85 to 120 degrees Fahrenheit higher than the melting point of the solder.
Grade	A title that indicates the melting and flow points of solder. There are five grades; extra easy, easy, medium, hard, and extra hard (sometimes called IT or intense temperature).
Ghost	A term used to describe blobs of solder that flowed outside of the intended join.
Hard Soldering	The joining of metals using a molten metal joining agent (solder) and temperatures over 1200 degrees Fahrenheit. The high temperatures needed for this technique are achieved with a torch.
Join	The point of connection; this is the area where you want solder to flow and solidify.
Melting Point	The temperature at which the solder will ball. This occurs just prior to the flow point of the solder.
Neutral Flame	A neutral flame has equal amounts of fuel and air. You will see a short light blue inner cone with a slightly rounded tip. The outer area of the flame is a darker blue and has a slightly yellow tip. There is no feather shape between the outer envelope and the inner cone. A neutral flame will have a low steady hissing sound.
Nonferrous	A material that doesn't contain iron. Generally used in reference to metal.
Overlay	Also called applique. A technique in which a metal piece is soldered to the top of a larger metal piece.
Oxidizing Flame	An oxidizing flame that has more air than fuel. This type of flame is the hottest and causes oxidation on the metal. The flame has a sharp inner cone and is accompanied by a loud raspy hiss.
Pallions	Chips of solder, usually about 1 x 1 millimeter.
Point of Contact Join	A soldering technique that joins a small point of contact between two pieces. Considered a difficult technique due to the size difference normally seen between the two metal pieces.
Quench	Cooling a soldered piece by immersion in pickle solution.
Reducing Flame	A reducing flame has more fuel than air. This type of flame is generally lower in temperature than a neutral flame and helps to ensure less oxidizing on the piece. A reducing flame has a blue cone with a light blue feather around it. The outer envelope of the flame is longer and a brighter blue than on a neutral flame.
Self-Pickling	A term used to indicate that a flux will help clean the metal during the application of heat. Items soldered with self-pickling flux still need to be quenched in pickle solution.
Soft Soldering	Joining metals together with a melted metal filler (solder generally made with lead and/or tin) at temperatures under 1200 degrees Fahrenheit. This process is most often performed with a soldering iron.
Solder Station	A fireproof, dust-free, non-cluttered area in which soldering is actually performed. Be sure to put safety and comfort first when putting your solder station together.
Strip Join	Also called a T-join. A soldering technique that joins two metal pieces, generally sheets, at a perpendicular angle. The use of a third hand can be quite helpful in this difficult technique.
Sweat Join	A soldering technique that is most often used to solder one sheet of metal to another. In this process, solder flows into the join through capillary action. This process is often considered the easiest technique to master.
T-Join	Also called a strip join. A soldering technique that joins metal two pieces, generally sheets, at a perpendicular angle. The use of a third-hand can be quite helpful in this difficult technique.

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