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Tips on Welding Sheet Metal

Welding sheet metal is a complicated job that necessitates precision, accuracy and safety procedures. One of the common problems often encountered by welders working with sheet metal is that they can easily make huge holes instead of welds. Without the proper skills and techniques, the heat can immediately melt the metal and the liquid metal will fall out of the part that is being fabricated.

When welding thin sheet of metal, the primary goal is to prevent distortion, burn-through and extreme heat-affected zones while making sure the weld has enough strength for the application. Contrary to popular belief, welding is not as simple and easy as heating the metal then fabricating it to the desired shape or size.

Specific types of sheet metal need specific control over heat. There are numerous welding processes that can be done to weld sheet metal such as short circuit transfer gas metal arc welding (GMAW), pulsed GMAW, gas tungsten arc welding (GTAW) and pulsed GTAW. Dissimilar components cannot be welded due to their varying melt properties and thermal conductivities. Nickel and chrome plated metals, for example, are easy to spot weld. On the other hand, sheet metals such as aluminum and tin need special preparation inherent to the coating metals.

The task of welding sheet metal starts from preparation and cleaning. Clean the metals, particularly aluminum, prior to welding. Use a solvent or degreaser to eradicate oil and dirt. Aluminum accumulates oxide layers when it is exposed to air. Before even welding it, remove the oxide using a stainless steel wire brush or chemical oxide removal solutions. Make sure the degreaser does not have any hydrocarbons.

Take note that aluminum oxide on the exterior of the material melts at 3,700 fahrenheit while the base-material aluminum will melt at 1,200 fahrenheit. Leaving any tinge of oxide on the surface of the base will hamper diffusion of the filler metal into the workpiece. Inefficiency in preparation degrades the quality of output, so be meticulous when cleaning it.

To ensure safety while welding sheet metal, you should work in a ventilated area to prevent build-up of harmful gas emission. Proper welding clothes, eyewear and leather gloves are also necessary. Sheet metal has sharp edges. Aluminum, in particular, is very springy and it can accidentally jump at you. Wearing the proper welding gloves can save you from a painful cut.

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