Brazing Rods

For clean and professional joints, brazing rods provide an economical solution to metal joinery. Forming a crucial part of the reliable brazing process, these filler metals create strong joints and are suitable for brazing by hand or in an automated process.

At Cromwell.co.uk you'll find high-quality and cost-effective brazing rods from the likes of GoGas International® and Sif®

Why brazing rods?

Using brazing rods for joining together two pieces of metal produces an extremely strong joint that can repel gases and liquids, withstand temperature changes, impact and vibration. Joints from this form of metal joinery have a clean and professional finish and allow for good control and flexibility over the materials used.

When are brazing rods used?

Used as the filler metal for brazing two or more metal pieces together, brazing rods are heated until molten and drawn into pre-set joints to form a strong metallurgical bond during cooling.

Brazing rod types

Brazing rods are identified according to the alloy they're made from. Each has its own melting range and advantages in use.

• Aluminium   -   Used to braze aluminium only

• Copper   -   Used in a vacuum, argon, and nitrogen atmospheres to braze steel and stainless steel

• Gold   -   Suitable for hydrogen and vacuum atmospheres to braze stainless steel

• Nickel   -   Same as Gold

• Silver   -   Melts at a low temperature, brazes steel, stainless steel, copper and nickel

Considerations when choosing a brazing rod

• Material - brazing rods should be chosen to suit the material to be brazed. For example, aluminium brazing rods can only be used to braze aluminium workpieces.

• Thickness - most effective at lower temperatures, brazing is, therefore, best to use with thinner materials and joints.

• Flux - brazing rods are bare, or flux coated. If purchased bare, then flux must be added separately to the joint. Flux can be purchased according to the brazing material, for example, Sif® supplies aluminium flux, and bronze flux in tubs of 500gms.

Brazing rod jargon buster

There are quite a few names and terms banded about when it comes to brazing. We want to make it easy for you, so we've described some of the most commonly used to help you find just what you're looking for.

• Acetylene - a hydrocarbon gas used in welding and brazing applications

• Propane - Liquified petroleum gas used to fuel hand-held torches for brazing applications

• MAPP® gas - Methyl Acetylene Propadiene Propane is a liquid gas that is safer to use than acetylene

• Flux - a chemical cleaning and purifying agent used to prevent the oxidising of brazed joints. Available as flux paste, flux powder, or as a treatment on brazing rods

• Butt joint - a brazing joint where two pieces of metal are butted up to each other

• Lap joint - an overlapping brazed joint that provides a strong bond

• Butt-lap joint - a combination of the two main brazing joints, this joint is self-supporting and benefits from the best of both the butt and lap joints

• Open-air - the name for brazing in a normal oxygenised setting, such as a workshop

• Controlled atmosphere - an inert atmosphere for brazing, often achieved using an atmospheric bell jar or vacuum furnace filled with a gas like Argon, nitrogen or hydrogen to improve the quality of joints brazed and prevent issues of scaling and oxidisation.

• High vacuum/high pressure - achieved using a fully sealed chamber, brazing in this atmosphere provides the highest quality results and is mostly used for medical and aerospace components.

FAQs

What's the difference between a brazing rod and a welding rod?

The difference is technique. Welding melts the base metal and fuses the joints together, while brazing melts the filler metal (provided by the brazing rod) to fill the joint between the two pieces via capillary action to join them together.

How do you use a brazing rod?

The brazing rod is heated to the required temperature before it is applied to the join of pre-positioned, braced parts. Once molten, the filler metal will naturally flow towards higher temperatures, so heating the opposite side to where this metal is placed draws it into the joint.

What equipment is needed for brazing?

Other than brazing rods to suit the material you wish to join, brazing requires a heat source, such as a brazing torch or furnace. Sometimes an induction heating system is used. If the brazing rods you've chosen are bare, brazing flux will also be needed.