How to Clean Metal before Welding
The statement “Cleaner is better” can be used as a blanket statement over all types of welding. The more diligent you when cleaning metal for welding the better your weld will be and that’s a fact. We decided to go over our most common weld cleaning supplies and why you would want them.
Stainless Wire Brush
A wire brush can be a versatile cleaning tool for weld joint preparation. We suggest getting yourself a few stainless brushes to clean metal with. These brushes should be marked for the type of material you’re cleaning them with and dedicated to only cleaning for welding. A low quality mild steel bristle wire brush will tend to rust and can put contaminants on the surface over time. Our stainless wire brush kit for welding will cover you for most jobs and last for a very long time.
Aluminum Weld Panel Prep
Aluminum tends to be more porous than mild steel and can hold contaminates in the surface which will pop up as you heat the surface and can cause issues mid-weld. By using an Aluminum Panel Prep you can spray the surface and wipe it down before you begin welding. Eastwood Aluminum Prep uses powerful oxidizers to ultra-clean the surface and remove any residue or stains in the surface before welding. We suggest using it as a last step before striking an arc on aluminum.
Anti-Spatter Saves Work
Sometimes it isn’t the weld surface itself you want to keep clean and free of debris, but the area out around the weld seam. If you’re ARC, Flux Core, or MIG welding you will be throwing sparks, slag, or debris over the entire project and the debris may be hot enough to stick to the panel and can be hard to remove. If the rest of your panel or part are nice and smooth and you don’t want slag sticking to it you may want to apply a light mist of Anti-Spatter to the surface to keep the area clean. You can simply wipe off the area using PRE paint prep and a rag. This sacrificial coating absorbs the heat and impact of the welding slag and will keep it from adhering to the metal. This saves extra finish work or potential damage to the metal.
Flap discs are attached to an angle grinder and have overlapping layers of sandpaper on them. This gives you an aggressive sanding surface for doing your first round of sanding on a piece of metal. Use a flap disc to remove the mill scale on metal or to bevel a weld joint during setup. We like to keep a few flap discs on hand in different grits for our 4.5″ angle grinder as well as small 3″ flap discs for small projects. These will get a panel clean and free of debris.
Non Woven Scuff Pads
If you need to touch up a clean panel or clean up a panel you left sit overnight you may not want to use something as aggressive as a DA sander or a flap disc. We suggest applying some PRE paint prep to the surface and scuffing it with a non-woven scuff pad just before you begin welding to make sure no oil or corrosion has started on the panel. The surface should be a dull finish and the scuff pads won’t leave any major scratches in the surface that would harm paint.