Discussion Overview
The discussion revolves around the issue of removing a brown chalky residue from steel after cleaning aluminum with sodium hydroxide. Participants explore various chemical and mechanical methods for cleaning without damaging the steel, including the use of electrolytic methods and the effects of different cleaning agents.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- One participant describes a brown chalky layer remaining on steel after using sodium hydroxide for cleaning aluminum and seeks a chemical removal method that does not affect the steel.
- Another participant questions the term "affecting" and suggests the possibility of etching.
- A participant mentions using sandpaper to remove scale residue but notes that it damages the steel and that alcohol and degreasers have been ineffective.
- There is a suggestion that sodium aluminate should have dissolved in alcohol, indicating it may not be the residue in question.
- One participant proposes sanding with fine grit sandpaper in the presence of a dilute sodium hydroxide solution to potentially dissolve some of the residue back into solution.
- Another participant agrees that oxidation is likely the issue and expresses a preference for sanding over using additional chemicals.
- A participant recommends using a concrete driveway cleaner or an electrolytic method for removing corrosion, noting that the electrolytic method can be adjusted for different types of rust and oxides.
- One participant expresses interest in trying the electrolytic method when time permits and mentions having most materials needed for the process.
Areas of Agreement / Disagreement
Participants express differing opinions on the best method for removing the residue, with some favoring mechanical methods like sanding and others advocating for chemical or electrolytic approaches. No consensus is reached on a definitive solution.
Contextual Notes
Participants acknowledge the potential for damage to the steel when using mechanical methods and the uncertainty surrounding the chemical nature of the residue. There are also concerns about the safety and handling of chemicals involved in the cleaning process.