1.What tools and materials are needed before processing?
Rust removal tools: sandpaper (coarse sand 60-80 mesh is used for large-area rust removal, fine sand 120-180 mesh is used for fine grinding), wire brush (manual or electric), rust remover (such as oxalic acid solution, special metal rust remover), rag or cotton yarn.
Anti-rust and repair materials: anti-rust paint (primer, such as red lead anti-rust paint, epoxy zinc-rich primer), topcoat (matching the original coating color of the color steel plate), sealant (silicone weathering glue or butyl glue, used for screw hole sealing), new screws (if the original screws are severely rusted and need to be replaced, it is recommended to choose galvanized or stainless steel materials), rubber gaskets.
Auxiliary tools: wrench, screwdriver, gloves, mask (avoid inhaling rust dust).
2.How to determine the degree of rust?
Mild rust: Only a small amount of rust appears around the screw hole, the coating on the steel plate is not damaged, and the screw is not loose.
Moderate rust: The rust spreads to 5-10cm around the screw hole, the coating peels or flakes off, the screw surface is rusted but can still be turned.
Severe rust: The steel plate around the screw hole is rusted or pitted, the screw is rusted and cannot be removed, and even the plate and the base are loose.
3.How to deal with mild rust?
Rust removal: Use fine sandpaper to gently polish the rust around the screw hole until the original color of the metal is exposed (avoid damaging the surrounding intact coating); if the rust is hard, spray a small amount of rust remover first, let it stand for 5-10 minutes before polishing, and finally wipe off the dust with a rag.
Reinforcement screws: Check whether the screws are loose. If so, tighten them with a screwdriver (pay attention to the strength to avoid screwing the threads). You can add 1-2 layers of rubber gaskets under the screw cap to enhance the sealing and fixation.
Anti-rust sealing: Apply a layer of anti-rust primer (thickness of about 0.1-0.2mm) to the screw hole and the surrounding 2-3cm range. After drying (about 2-4 hours), apply a layer of topcoat in the same color as the color steel plate. Finally, apply a circle of sealant (width 1-2mm) along the edge of the screw cap to prevent moisture from penetrating.
4.How to deal with moderate rust?
Thoroughly remove rust: Use a wire brush or electric rust removal tool to remove all rust and peeling coating around the screw hole. If the screw is severely rusted, spray the rust remover and try to remove it with a wrench. If it cannot be removed, use an angle grinder to grind the screw cap flat and then re-drill the hole.
Repair the base layer: If small pits appear on the surface of the steel plate due to rust, fill them with putty and polish them flat with sandpaper after drying to ensure a smooth surface.
Replace screws: Remove the old screws, replace them with galvanized or stainless steel screws, tighten them again, and add rubber gaskets.
Coating and sealing: Apply anti-rust primer first, then topcoat, and finally apply sealant to the screw holes and joints. The glue layer must cover the entire edge of the rust repair area to ensure a complete seal.
5.How to deal with severe rust?
Local repair: Use an angle grinder to cut off the severely rusted area. Cut a piece of color steel plate of the same material and thickness as a patch, and grind the edge to a 45° bevel. Apply sealant on the back of the patch, cover the cut, and fix it with rivets around the periphery to ensure that the patch fits tightly with the original plate. Grind the edge of the patch, apply anti-rust primer and topcoat, and then seal the entire patch with sealant.
Replace the plate: If the rusted area is too large or the plate has been deformed, it is necessary to partially replace the color steel plate, and at the same time check whether the base keel is rusted, and replace it if necessary.