I'm a new welder, but I grind the bad stuff with a grinding wheel, then shine it up with 80 grit flap wheel, then spray it down with brake cleaner. When completely dry, I weld.
Clean wire wheel on the grinder dedicated to metal prep. Spray w/ brake cleaner (the fast evaporating kind) and weld away. Works great.
Very old thread, but it's never to late to learn about safety, NEVER weld on metal that has been cleaned with brake cleaner, here's a quote from the 'thefabricator.com" web site,
Quote " In the May/June issue I talked about common solutions to pinholes. While I was focused on the question at hand, I inadvertently neglected to address a particularly dangerous practice that Marv B. mentioned.
He stated in his question that prior to welding he “tried cleaning them [the components] with brake cleaner.” This is disturbing as the combination of welding and brake cleaners can lead to serious illness, permanent damage to your internal organs, or even DEATH!!!!!
Many warnings are found on the chemicals that we use every day. Often I simply assume that if it’s sold over the counter surely it must be safe, but that’s just not the case this time. The Safety Data Sheet (SDS) for a can of brake cleaner reads:
“Do not use this product near open flames, welding operations, or excessive heat. Vapors may decompose to harmful or fatal corrosive gases such as hydrogen chloride and possibly phosgene.”
This can be debilitating or even deadly to the welder or those around him or her. According to the Centers for Disease Control and Prevention (CDC), phosgene is an industrial chemical used to make plastics and pesticides. It does not occur naturally and was used extensively in World War I as a choking agent.
It is poisonous at room temperature and can cause coughing, burning in the throat and eyes, blurred vision, shortness of breath, nausea, vomiting, and pulmonary edema. Some of the more serious effects can show up 48 hours after exposure, and those include difficulty breathing, low blood pressure, and heart failure.
Chronic bronchitis and emphysema are reported permanent side effects of phosgene exposure. In other words, if it doesn’t kill you, it’s going to alter your health significantly. "end quote
Just a little more info, even after the brake cleaner has dried on the part that your cleaning, if that area is welded on it will still produce phosgene gas ,
When it says that phosgene was used extensively in World War 1 in the above info, most people know that product as mustard gas, not something you want to mess with or take lightly,