To make a high quality TIG weld, cleanliness of the material is equally as important as proper technique. And when I say ?material?, I?m talking both the base material you are welding on AND the filler material you are using. The following are some good points to remember when preparing to make your weld:
Make sure to remove all paint in a wide enough area around your weld zone. The ability to control how much heat you put into material is definitely one of TIG?s best features, but heat travels pretty quickly through thin material. I know you probably want to minimize the amount of paint touch-up that you do, but repairing burnt paint takes time too and it?s really not worth the potential health risk from the fumes.
Make sure to wipe off all oils and their residue. Left in the weld area, these materials can cause porosity (that Swiss cheese look in your welds) that weakens the weld. If you choose to use a chemical degreaser, make sure to use a substance that completely evaporates off and doesn?t leave a residue behind. Don?t just grab your brake cleaner and think its ok! Check the container label to make sure that there aren?t any warnings against its use around a weld arc.
Remove all surface rust and oxides off of the base material and filler rod. Just like oil, rust and other oxides can contaminate the weld. Use a wire brush or abrasive pad (like Scotchbrite?) to remove these. When welding aluminum, make sure to use a dedicated (used only for this material) stainless steel wire brush or pad. This prevents contaminating this material with the carbon from a mild steel brush or other materials.
Keeping your material clean will help you produce those pretty, high quality welds you are looking for when using TIG!