This isn’t art-related, but these sorts of projects take up a lot of my time and energy so it seems relevant. I epoxied our stone bathtub with Klass Kote (custom color Insignia Blue). It was quite the endeavor, but it came out great. If you are planning to use this epoxy or similar, for the love of god wear a properly fitting respirator with new cartridges, goggles, and chemical resistant gloves. Also move your pets out of the house and prepare to sleep outside/elsewhere for at least one night.