SOLDERING Processing Manual passion vision innovation

In the past, present, and also in the future, "soldering" as a joining technique has been and will be an important part of dental-lab procedures. Soldering is the most frequently used joining technique for metals. In order to obtain a soldering joint, the necessary materials must be processed with utmost care. It also involves thorough knowledge of the materials and their correct technical application. This Manual will provide you with the most important information about soldering before and after ceramic firing. In this way, you will be able to fabricate even more successful restorations for...

Past / Present / Future Joining Technique "Soldering" 4 Surface Tension / Diffusion Solder Joint Soldering Accessories Torch and Flame Control Surface Preparation Pre-Soldering (Before Ceramic Firing) Post-Soldering (After Ceramic Firing) 1 Alloy Table Solder Table Trouble Shooting Short Instructions: Pre-Soldering Short Instructions: Post-Soldering

Past The ancient Egyptians melted gold and used the material to fabricate beautiful artifacts as testimony to their sophisticated culture. Soldering has also been practiced since the earliest days of history. The soldering technique of those days involved copper ore and helped goldsmiths fabricate the finest jewelly. In dentistry, soldering has been used for more than 100 years. Present Given its universal application possibilities in dental-lab technology, soldering has not lost its importance despite modern welding techniques and adhesive procedures. In dental laboratories, the number of daily...

Soldering is a procedure to join metal components with the help of a molten joining metal with a processing temperature below the solidus temperature of the alloys to be joined. The solder wets these alloys without melting them during soldering. During the soldering procedure a reciprocal diffusion between the liquid solder and the solid-hot alloy takes place. mThe decisive factors for the long-term success of the solder joint is the bond strength (quality of the diffusion structure) and the corrosion resistance.

Solders Given the required resistance to the oral environment, only hard solders are used in dental-lab technology. Depending on the designated use, solders are classified as high-fusing solders with a processing temperature of approximately 950–1,200 °C / 1742–2192 °F and low-fusing solders with a processing temperature of approximately 700–900 °C / 1292–1652 °F. A high fusing solder should always be selected first. To allow additional repair procedure to be accomplished with a flow fusing solder. The solder and alloy must be compatible with each other. Please refer to the solder table in the...

Surface Tension / Diffusion Good wetting of the alloy with the molten solder is a prerequisite for a successful soldering procedure. With optimum wetting, the solder spreads out evenly over the alloy, wets both surfaces, and fills the soldering gap. The formation of droplets by the solder is a sign of poor wetting. As a result, the solder does not flow and diffusion does not occur. Diffusion refers to the process in which certain metals of the alloy and the solder are mixed. A diffusion structure is formed at the interface. A sufficiently high temperature of the framework elements to be joined...

A "solder gap" is an even distance of 0.05 to 0.2 mm between the framework elements to be joined by soldering. For that purpose, the soldering surfaces must be parallel. Wider gaps are not suitable. During cooling, the solder contracts more than the soldering base and the framework element expand during heating. This is due to a solidification shrinkage of the liquid solder. The consequences are torsion of the framework elements, inadequate flow of the solder and solder joint crack. To maximize the capillary effect, framework elements should be parallel to one another with the recommended gap...

Oxidation Soldering requires heating of the alloy, which always results in oxidation. Oxidation is a reaction with oxygen. It occurs in all the alloys. The higher the base metal content, the more pronounced is the oxidation. In order to prevent oxide formation, an appropriate flux may be used. The flux breaks down the oxygen compound of the alloy surface. During this dissolution procedure, the oxides are absorbed by the flux and protect parent alloys from further oxidation. A non contaminated surface then enables optimum wetting by the solder. To optimize the use of flux the soldering procedure...

Soldering Accessories The prerequisites for a sound soldering procedure are as follows: clean metallic surfaces, a flux that will dissolve the oxides, framework elements that have been evenly preheated to the processing temperature, and a soldering gap (0.05–0.2 mm) with walls as parallel as possible. High-fusing Bondal™ Flux Bondal™ Flux Flux for solder with a high processing temperature: > 960 °C (soldering before ceramic firing) Flux for solder with a low working temperature: < 900 °C (soldering after ceramic firing and for universal solders) Magic wand A torch system with a safety valve enables...

Torch and Flame Control For dental soldering procedures, mainly propane torches with compressed air or oxygen are used. Open flame Carbon rich zone Reduced zone – optimum zone for soldering Oxidizing zone The correct setting of the flame, oxygen/propane or air/propane mixture, and the selection of the burner nozzle/ burner head are critical for reliable soldering. Multi-orifice torches produce a large, soft flame. In conjunction with a propane-compressed air mixture or a propane-oxygen mixture, these torches are suitable for even heating of the object to be soldered. Single-orifice torches produce...

Clean soldering contact surfaces are a basic requirement for optimum wetting. The surfaces of the soldering contact areas have to be prepared by grinding and/or sand blasting. Evenly roughen the soldering contact surfaces in the direction of flow of the solder using a suitable (ceramic-bonded) grinding instrument. The soldering contact surfaces may also be blasted with 50 micron AhOs. The soldering contact surfaces should have dimensions adequate for the intended stressbearing situation.