Getting Rid Of The Oxide Layer
Once you begin to TIG weld with your Everlast AC/DC PowerTig, no doubt, you’ll want to begin welding aluminum at some point. Try to resist jumping right into aluminum first if you can. One of the problems with welding aluminum is that it isn’t very forgiving. Welding aluminum before you learn to TIG weld steel is like jumping into an advanced calculus course, before you learn algebra. Starting on steel first is recommended. Steel allows more forgiveness in the weld technique, and melts more controlled so you have more time to add the filler. It also changes color, where aluminum does not offer much indication when it melts.
But with that said, welding aluminum is not impossible of course. One of the biggest issues that presents problems is the fact that aluminum oxide layer is quite heavy, and resists melting. In fact it’s melting point is twice that of the aluminum hiding under it. This should be cleaned off with a stainless wire brush before welding, so that the aluminum can be exposed. Further cleaning with acetone or aluminum cleaner is recommended. It’s not necessary to grind away the metal itself, but a thorough brightening of the metal is required. This aluminum oxide layer will appear as a gray film on the surface of the metal while it is being welded if it is not cleaned. In fact, the metal will actually melt completely and blow out a large spot if the weld still has it’s oxide layer intact, and you will not know it until it happens, because the layer under the oxide has already melted and a thin stubborn layer of oxidation will “pretend” that nothing has changed.