Many older bathtubs are made of an enamel or porcelain coating over a metal base. Over time, this more delicate topcoat can become cracked, exposing the metal layer beneath. Once this metal is exposed, it can be prone to rust. It's in near-constant contact with water and air, so it's no surprise it will oxidize very quickly.
Many think that when an older bathtub becomes rusty, it's time to replace the entire unit. But there are actually methods of do-it-yourself rusted bathtub repair that can help restore your tub to its former glory.
Cleaning a Rusted Bathtub
The first step to repairing an old rusted bathtub is a thorough deep cleaning. It's worth beginning by giving your entire tub a thorough deep cleanse with a bathroom cleaner and a cloth. Any grease, grime or soap scum will interfere with the later stages of restoring your bathtub, so starting with a clean slate is the best way to go.
MaidSailors.com suggests using a product like Bar Keepers Friend for cleaning the specifically rusty areas. You must open a window when using products like this for ventilation and to ensure moisture can escape from the room, as any humidity in the air could cause more rust.
Removing Rust From a Bathtub
The first step for removing rust from a bathtub is to sand down any excess. Landmark Home Warranty recommends using fine sandpaper or a steel brush to create a smoother surface. You want this surface to be as flat as possible to allow the epoxy to form a watertight and airtight seal over the area.
If the rusted area has also left a stain on the surrounding enamel, this can be lightened using standard household products. GC Plumbing recommends using either lemon juice and salt or vinegar and baking soda applied in a paste to the affected area. The mixture should be left to dry then removed with a cloth and warm water.
Repainting a Rusted Bathtub
Once your bathtub is totally clean and your rust patches are as smooth as possible, you can begin the cover-up process. So long as the structural integrity of your bath remains sound, Today claims that reglazing is a perfect method of covering up minor scuffs and rust patches. You should always wear safety gear (a respirator mask rated R95 or above, gloves and safety glasses) when reglazing a rusted tub. Plus you should cover your floor and your bath's taps.
You'll first want to apply a layer of primer to help your new glaze apply smoothly and last a long time. Apply one or two layers of acrylic polymer paint to the affected area, allowing for adequate drying time in between. You can finish with an extra layer of bond sealant to protect your paint job and keep your new coating watertight.
In order to prevent future rusting issues, there are a few techniques PlumbWorld recommends to protect your bath. Not allowing metal cans to sit along the edges of your bath can help, along with making sure to treat limescale and mineral deposit buildup quickly and efficiently. Generally, wiping down your bathtub after use can be the best way to minimize rust issues in the future.