Kemppi Max WeldClean Multi Large Parts FAQs
Practical answers on the brushes, sleeves, bushes, adaptors, fluid and containers used with large-head electrochemical weld cleaning attachments.
How does an electrochemical weld cleaning brush work?
A carbon fibre brush carries electric current into the weld area while it is kept wet with a cleaning fluid, normally a phosphoric acid solution. The current and fluid together remove the heat tint and oxide left by welding on stainless steel, which helps restore corrosion resistance. The brush is the part that touches the work, so it is the main wearing part.
The brush and the surface must both stay moist. In some systems, the power cuts out automatically if the brush lifts off the work, which helps prevent burn marks. Always follow the instructions for your particular cleaning system.
How do I know when to replace a carbon brush?
There is no single wear figure that applies to every brush, so use the maker's guidance for your system. In practice, replace it when it has worn short, frayed or damaged, when the finish becomes patchy or slow, or when the brush no longer sits firmly in its holder. A brush used at higher current generally wears faster, and welds that need more current can mean more frequent changes.
Some sleeved brushes can be adjusted or trimmed to expose fresh fibres, but only do this if your maker's instructions allow it. Keep spare brushes to hand so cleaning is not interrupted.
What is the cleaning fluid and what safety precautions does it need?
Weld cleaning fluids are commonly a phosphoric acid solution, chosen to suit the job. They are acidic, so follow the safety data sheet for the product. Wear eye, face and hand protection, including chemical-resistant gloves, work in good ventilation and use respiratory protection where needed.
Treat the fluid as a hazardous substance. Suppliers generally provide a safety data sheet, and your chemical risk assessment should cover use, spills and first aid. Never mix it with other chemicals.
What should I do after cleaning a weld?
Turn off the current and lift the brush, then neutralise and rinse the area as your system's instructions call for, and wipe it dry. Use clean cloths so that the acid is not spread to other parts of the work. If acid is left on the surface it can leave white blotches or staining, so do not skip this step.
Also wash and rinse the cleaning equipment thoroughly after use, which avoids acid damage and keeps the equipment in good condition. Wipe up any spills straight away and dispose of used cloths and waste as your safety data sheet and chemical risk assessment advise.