3 Best Ways on How to Braze Metal Like a Professional

Brazing joins two pieces of base metal once a melted metallic filler flows across the joint and cools to make a strong bond. It produces a quite solid joint, usually firmer than the base metal pieces themselves, without melting or deforming the components.

Two different metals, or base metals like silver and bronze, are ideal for brazing. Apply this method to create a bond that is invisible, resilient in a wide range of temps, and can withstand twisting and jolting motion.

Of all the techniques available for metal joining, brazing may be the most versatile. Brazed joints have high tensile strength since they’re often stronger than the two metals being bonded together.

Brazed joints repel liquid and gas, withstand shock/vibration, and are unaffected by regular changes in temperature. Due to the metals being joined aren’t themselves melted, they aren’t warped or otherwise distorted and “keep” their original metallurgical preferences.

You can braze pipes, flat metals, rods, or any other configuration as long as the pieces fit neatly versus each other without large gaps. Brazing also manipulates more unusual shapes with linear joints.

What Metals can be Brazed?

Many different kinds of metals can be brazed. Copper, and copper-based metals such as bronze and brass, are typically brazed with copper phosphorus alloys also known as AWS (American Welding Society) BCuP filler metals.

Tool, mild, and high alloy steels, stainless steels, precious metals, cast iron, monel, inconel, carbide, nickel, brass, copper, and bronze materials are typically brazed with silver brazing filler metals from the AWS Bag family.

Aluminum is brazing metal that is frequently used in the industry, but it needs different filler fluxes and metals than those mentioned above.

Why Braze Metal?

When thinking which metal joining process to opt for a particular assembly, several factors should be included:

  • strength and permanence,
  • the physical properties of the parts,
  • the shape of the joint,
  • and the production level required.

Brazing is recommended when permanence and strength are primary considerations. Since in brazing filler metal is always used and generally the complete joint area is heated simultaneous, brazing is quite a robust process.

Brazing is excellent for joining different metals with similar melting points. Hence, for many metal joining operations, brazing becomes the most logical option.

The benefits and versatility that brazing brings are fully realized when the heating process is carefully considered at the configuration design phase. Therefore, parts once visualized and fabricated as monolithic, one-piece units’ machines out of solid bar stock, now can be often manufactured more quickly and economically by brazing together one or more metal elements.
Due to a variety of metals can be utilized, brazing provides brazers to optimize joint functionality, weight, and economy.

Costly machining, casting, and forging operations can be avoided without assembling the integrity of the joint, and lower cost raw components like sheet metal, stampings, and extrusions can be applied. The producing process becomes easier, quicker, and finally more profitable.

Brazing Procedures

A brazed joint essentially can make itself capillarity, more than brazer skill enables filler metal transfer into the joint. The real power lies in the design and engineering of the joint, but even a properly designed joint can come out inadequately, if you don’t follow the proper brazing procedures.

These procedures include 6 key steps listed below:

  • Proper fit and adequate clearances;
  • Clean the materials;
  • Flux the portions;
  • Assembling;
  • Braze the assembly;
  • Clean the brazed joint.

How to Braze Metal

Metals can be joined together by inductive heating with the help of brazing filler metals. Due to the versatility of the induction heating and the matching brazing filler metals, it’s achievable to mix and join ferromagnetic and non-ferromagnetic materials mutually.
Follow these 5 steps on how to braze metal like a professional:

  • Apply emery cloth or wire brush to scrape the metal surface. Then clean the surfaces using a degreaser or soapy water;
  • Now, position the metal properly. Typically, an overlapped joint will be sturdier and braze together simpler than a gapped joint. If required, use a vice to ensure the parts in position;
  • Glow the joint where two metal sections will meet until the joint heats;
  • Apply the brazing rod to the joint as continuing to glow the metal surfaces. For large areas, heat portions of the joint to the required temperature and then proceed with the next adjoining area;
  • After brazing, take a wire brush to clean the brazed space and eliminate any residue or oxidation.

How to Braze Aluminum

Brazing of aluminum can be a valuable skill for anyone who is challenged with various at-home repairs. Brazing aluminum is a fast and inexpensive solution for repairing holes, leaks, or cracks in aluminum, and is most commonly used in air-conditioning repairs.

When compared to welding equipment, aluminum brazing gear is low-cost, mobile, and doesn’t need high amounts of voltage.
In case you don’t know how to braze aluminum, just read these 8 brazing aluminum steps with detailed description:

  • Wear non-flammable gloves, clothing, and safety glasses before you start the brazing operation;
  • Clean all dirt, oil, paint, or other residues from the space to be fixed by aluminum brazing. Apply a degreasing solvent to eliminate oil and grease. Depending on the size of the repaired surface, you may need to sandblast the surface or use a file or an emery cloth;
  • Use a vice to support the aluminum to be brazed;
  • Take a brush to apply the flux suitable to the temperatures and the metal. An all-purpose flux envelops a wide range of temperatures and is practical for general purpose brazing. Add flux by immersing the filler rod into the flux. You may also utilize flux-coated rods to skip this step. The flux-coated rods use the flux during the aluminum brazing;
  • Heat the fixed area with an acetylene or propane torch until the aluminum shows an orange bloom. It occurs when the metal gets very hot. Once you use a flux, it should alter colors or turn clear all over the surface;
  • Use the filler metal by running a brazing rod along the joint or the crack. The metal heat will melt the filler into the surface requiring the repair. Use the flame of the brazing torch as necessary to melt the rod;
  • Pull off the flux after the filler material has hardened through immersing the part or pouring hot water on the repair. The flux will peel off. If it doesn’t flake off, apply a wire brush to softly scour the brazed surface while wet or still in the warm water;
  • Polish the surface with an emery cloth after the joint has cooled entirely.

How to Braze Steel

Brazing is an excellent method for joining two different types of steel, or when you don't need as strong physical bond, and aesthetics or low distortion are important. So, keep track on these 6 steps and learn how to braze steel:

Step #1 Preparation

The steel must first be cleaned, so dirt and grease are eliminated. Emery cloth or wire tool are the most suitable abrasives.

A powder is combined with water to make a paste which is brushed along the joint. Flux “blocks” oxidation process on the metal surfaces as this would stop brazing being successful.
Step #2 Use Brazing Torch

The brazing torch is turned on, and this pressurizes the air and gas. While the gas-air control is slowly turned on, gas is fed by the nozzle, and it's kindled via a pilot light on the nozzle with a match.

Step #3 Flame adjusting

Once ignited the gas-air control is turned to let more air/gas into the nozzle which provides a longer, more intense flame. The flame’s length can be adjusted with the control until the desired amount of flame is accomplished.

Like a rough guide, a blue section of flame will come out close the nozzle, and the end of this is the hottest fraction of the flame.

Step #4 Making the Joint

The two pieces of steel should be positioned on the rotating table. Fire bricks should also be located at the back and sides of the metal so that heat doesn’t release and is reflected back.

The steel provides gentle overall heating which increases the temperature slowly. It enables the steel to extend gradually and for the water in the flux to vaporize without moving out of position. The flame is transferred around the joint quite promptly during this first phase of heating.

Step #5 Joint heating

The flame is then transferred forward with the blue tip of the flame nearly touching the steel. The focal point of heat should now be on the joint, as the flame is slowly moved forward and backward along it.

The joint will become fairly hot and occurs in red color.

Step #6 Rod melting

A brazing rod is then pushed smoothly versus the joint, and if the temperature is proper, the end of the rod will melt and start to run along the joint. The rod is fed into the joint until a brazed joint is finished.

Now, brazing steel is allowed to cool slowly. If cooled quickly, like quenching in water, the joint can crack or become distorted.

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