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We will be at the Georgia World Congress Center in Atlanta January 14 through January 16 for the 2019 AHR Expo.  Technical experts will be on hand to discuss your newest brazing projects and troubleshoot brazing issues.  Learn more about the ChannelFlux family of alloys, aluminum brazing, and the latest changes at Bellman-Melcor!

Bellman Christmas Party

December 26, 2018

On December 21 our annual Christmas party was held at Gatto’s in Tinley Park.  We held a raffle, enjoyed fabulous food (and drinks!!), and had our ugly Christmas sweater contest.  Contestants were judged via applause and Marshawn came out on top!  As the winner, he went home with a gift card.

We are a proud returning exhibitor at AHR Mexico 2018 and are thrilled to announce our inaugural exhibit at Chillventa 2018 in Nuremberg, Germany!  We will have technical experts at both of these shows ready to troubleshoot your brazing issues.

The biggest problem faced by operators new to aluminum torch brazing is the close proximity of the brazing alloy’s melt temperature to the melt temperature of the assembly.  This can be especially problematic when brazing air-conditioning coils, where there are many braze joints in one concentrated area.

Aluminum base metals present a number of challenges during brazing.  First, the low melting temperature of aluminum base metals requires more precise heat control, and the lack of color change that occurs during heating doesn’t give braze operators any visual indication that the base metal has reached the proper brazing temperature.

Cutting tools like drills, dies, and machine tool bits as well as masonry, rock and mining drills are frequently made with carbide.  At fast cutting speeds, carbide increases the life of the cutting edge.

While many mechanical fastening methods have been tried to secure carbide to tools, brazing with a silver alloy is the most successful and widely used method.  Using silver brazing shims, carbide can be attached to the shank on as many or as few sides as necessary, requires no additional space, and can be replaced or salvaged by melting off and re-brazing.

We are pleased to welcome Creed Darling to Bellman-Melcor as our new Director of Technical Services!

Prior to joining Bellman-Melcor, Creed spent 5 years in operational roles including Plant Manager and Director of Operations in the power sports and metal joining industries respectively.  Creed also spent 10 years in applications engineering and product management roles, where he was responsible for directing efforts in applications support and product development. 

There are a variety of reliable metal joining methods.  Why choose to braze your application as opposed to any other method of joining?  Evaluating the appropriateness of brazing for your metal joining application requires consideration of the part’s end service requirements, such as corrosion resistance and stress level the part will encounter.  Before you choose brazing, consider the following:

Although it requires practice, brazing of aluminum to copper can be successful using a tightly controlled process.  The most appropriate technique to use when joining these two base metals is flame brazing, using a low-temperature melting flux and brazing alloy.  While the process of brazing aluminum to copper is similar in nature to the process of brazing aluminum to aluminum, certain steps must be taken to insure a quality braze joint.

Milk of Magnesia, which is readily available at most retail outlets, can be as effective a braze stop as any stop off products.  A typical stop off is a mixture of metallic oxide powders and a liquid; plain Milk of Magnesia is a suspension of powdered magnesium hydroxide in water. When Milk of Magnesia is heated, the water boils away, leaving the solid magnesium hydroxide. Continued heating (to just above 600° F) releases the water from the magnesium hydroxide crystal structure, leaving plain magnesium oxide. Together these components form a suspension or slurry that can be applied to the area where you do not want braze to flow. While it’s common for manufacturers to add color to their particular suspension for marketing purposes, the results are the same.

On a basic level, brazing aluminum is similar to brazing other base metals.  However, aluminum’s low melting temperature, lower melt temperature brazing alloys, and specialized fluxes make brazing aluminum a unique process.

3000 series aluminum is the most frequently brazed aluminum base metal, but certain 6000 series aluminum may also be used.  Very few cast aluminum and 5000 series alloys can be brazed, and extra care must be given during the brazing process to insure success.

Identification of an application’s function, selection of materials, definition of an application’s shape, and selection of an appropriate brazing process are the four essential engineering decisions contributing to a successful brazing operation.  If there is a problem with your brazing operation, it can be avoided or resolved by manipulating any of the four aforementioned variables.

A preform, a manufactured shape of brazing filler metal, may be pre-placed in an assembly prior to automated brazing. Made from bulk wire or strip, preforms include rings, washers, discs, shims, edgewounds, and custom shapes.

Addressing the narrow thermal processing window is perhaps the biggest concern when considering an aluminum brazing project.  The problem, simply stated, is that the aluminum base metals melt at about the same temperature as the brazing filler metal.  

Brazing Carbide

January 26, 2017

Silver brazing shims have proved the best way to secure carbide to tools.  Shims require no additional space and can be replaced or salvaged by melting off and re-brazing.

Torch and induction brazing are the most adaptable processes for joining carbide tips:  torch brazing for occasional work or in cases of varying size, and induction brazing for a production environment.

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Silver
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