How do I get rust stains out of granite?
To determine how do you get rust stains out of granite you must first determine the source of the stain. Was this rust stain caused by rusting metal on top of the granite absorbing into the stone or was the rust due to the iron oxidizing from within the granite?
Granite Rust From External Reactions
Rust stains caused by rusting metal absorbing into the surface of the stone can typically be removed using a specific rust remover poultice like Lustro Italiano Rust Remover Powder. The rust remover poultice contains a special blend of chelates for removing rust stains from stone. By utilizing the stain process reversal technique the Lustro Italiano Rust Stain Powder draws the stain out of the stone.
Many stains require multiple applications of the poultice to completely remove the stain. Calcium based stones such as marbles could become etched requiring repolishing. It is always recommended to reseal the stone surface with a quality penetrating sealer after the stain is completely removed and any necessary polishing has been completed.
A "Deeper" Look at Granite Rust
When rust stains occur due to iron oxidizing with the granite, the results are not always positive and proven. Using the rust remover as described above, the poultice may lighten or remove the surface staining. The issue is that there is rusting going on inside the stone and it may come back. After using the poultice, if the stain has been removed, you may reseal the granite with a penetrating sealing to help slow the rust stain from appearing on the surface again, but this is not a proven technique. To remove rust from granite in this manner we are still in the research and development phase.