One question you see on-line a lot especially when working with slate is should you coat them with lacquer or not.

Me I always put a base coat of matt lacquer down first – this seems the make the engraving go down better to start with, and I always put a final clear coat of matt lacquer on the coasters afterwards. This final coat seals the coaster but also really makes the engraving pop.

The example below is from a customer this week both slates were treated with Rustomleum Matt Clear Lacquer before engraving. The one on the right was then coated again after the engraving had finished. You can really see here this difference it makes.