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Blog archive

2012, September

TIG Welding Aluminum

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Although many metals are TIG welded, the metal most frequently associated with the TIG-welding process is aluminum, especially with metals of a smaller thickness. Any other processes, of course, can join aluminum, but in the lighter gauges, the most acceptable process is TIG. The popularity of aluminum in automotive applications has brought TIG welding to a new golden age. Mechanically strong and visually appealing, TIG Welding is the #1 process chosen by professional welders for professional racing teams, auto enthusiast, and hobbyists.

That Confusing Thing About Aluminum The process is well-suited for aluminum, but there are a few character issues of the metal that bring up points that must be considered if this material is to be welded with consistent ease and quality. The pure metal has a melting point less than 1200°F and does not exhibit the color changes before melting so characteristic of most metals. For this reason, aluminum does not tell you when it is hot or ready to melt. The oxide or “skin” that forms so rapidly on its surface has a melting point almost three times as high (3200°+F). To add to this confusion, aluminum even boils at a lower temperature (2880°F) than this oxide melts. The oxide is also heavier than aluminum and, when melted, tends to sink or be trapped in the molten aluminum. For these reasons, it is easy to see why as much as possible of this oxide “skin” must be removed before welding. Luckily, the reverse polarity half of the AC arc does an outstanding job of clearing off quantities of this oxide ahead of the weld! That Aluminum is Hot! Aluminum is an excellent conductor of heat. It requires a large amount of heat when welding is begun, since much heat is lost in heating the surrounding base metal. After welding has progressed a while, much of this heat has moved ahead of the arc and pre-heated the base metal to a temperature requiring less welding current than the original cold plate. If the weld is continued farther on to the end of the two plates where there is nowhere for this pre-heat to go, it can pile up to such a degree as to make welding difficult unless the current is decreased. This explains why a foot or hand Amptrol™ (current control) is recommended with your Square Wave TIG 175 or Square Wave TIG 275 – it enables you to easily change the current while simultaneously welding. Some aluminum alloys exhibit “hot short” tendencies and are crack-sensitive. This means that at the range of temperatures where the liquid alloy is slushy (part solid and part liquid) or just turned solid, it has not quite enough tensile strength to resist the shrinkage stresses that are occurring from cooling and transformation. The proper choice of filler metal and welding procedures, along with smaller beads, can help eliminate many problems of this kind. Some experts recommend backstepping the first inch or so of each aluminum weld before finishing in the normal direction. Filling the Gap The metal produced in the weld pool is a combination of metals that must have the strength, ductility, freedom from cracking, and the corrosion resistance required by the application. Correct choice of filler alloys minimizes the presence of intermetallic compounds and brittleness in aluminum fusion welds. See table below for recommended filler metals for various aluminum alloys. Maximum rate of deposition is obtained with filler wire or rod of the largest practical diameter while welding at the maximum practical welding current. The wire diameter best suited for a specific application depends upon the current that can be used to make the weld. In turn, the current is governed by the available power supply, joint design, alloy type and thickness, and the welding position.
NEW! K22 Motorcycle Wheel Balancer
The K22 Motorized wheel balancer has a fixed shaft, enabling the wheel to rotate freely on its own bearings. This simulates the assembly of the wheel on the motorcycle and eliminates all the assembly inaccuracies which are inevitable with traditional balancing machines for car wheels, where the adapter is put in rotation with the wheel. Improvements have been made to the K22 include electronic sensors, which automatically detect the wheel diameter and offset. Entering wheel dimensions is now super-fast and error-free with the K22. It has an unbelievably fast set-up and balance time due to the advances in mounting simplicity and updated electronics. The “Fixed Shaft” allows the motorcycle wheel to spin on its own bearings, exactly reproducing the conditions of the wheel when it’s on the bike. Balancing is much more accurate; wheel bearing defects can be detected and putting wheels on the balancer is far quicker and easier than converted automotive balancers. The K22 will handle wheels up to the 240/250 size right out of the box, and an adaptor is available to balance 280’s, 300’s & 330’s. Balancing wheels from singled sided swing-arms is accomplished by the Universal Adaptor for bearing-less wheels. Features of the CEMB K22 Motorcycle Wheel Balancer BALANCING BOTH PLANES: Static (regular) and Dynamic (wider than 4") ULTRA-FAST SETUP: Stationary shaft. (No adapter drive forks/arms to adjust) DIAGNOSE WHEEL BEARINGS: Stationary shaft allows tech to hear noisy bearings DETECT OUT-OF-ROUNDNESS: Abnormal vibrations are felt through control lever FREEDOM FROM ERRORS: Digital electronics guarantee accuracy and reliability Specifications of the CEMB K22 Motorcycle Wheel Balancer RIM DIAMETER: 10" to 24" DISTANCE BETWEEN WHEEL BEARINGS: Phone for Current Specifications POWER REQUIREMENTS: 120V, 1 phase; or 12V DC ULTIMATE ACCURACY: ±1 gram, 1/10oz.
New Transmission Fluid Exchanger!

We have recently added the Symtech ATF1 Transmission Fluid Exchanger to our product line. It features free shipping and no sales tax. The new ATF 1 Automatic Transmission Fluid Exchanger incorporates the most advanced technology of today. The ATF1 features Cooler Line and Dipstick modes of operation, and includes an onboard battery. This unit is structured so that new and used fluids never come into contact with each other. The Power On/Off switch prevents battery arching hazard. Another great feature, is that it includes level sensor technology, so it never needs calibration. The fluid measurement capability is precise, right down to the tenth of a quart. It also includes an external mounted filter for easy maintenance. Comes complete with audio and visual prompts and warnings for ease of use. Note: Adapter kit is included.