Maybe the tile project had to be halted in a hurry to care for the little things that get in the way of big projects. Maybe the project got away from you and the mortar has stuck to your otherwise pristine tiled surface. No matter the reason, removing dried mortar from slate tiles isn't a difficult task to complete. Depending on the time it has had to dry and the area of the job, there are a few ways to remove dried mortar and let those slate tiles shine.
First Line of Defense
If you don't have a large area or the mortar is just a few hours or days old, there are many ways to wipe away the dried mortar in a small amount of time. A cloth can be used to rub away the dried mortar, but that can add up to hours of tedious work. A Dremel rotary tool with different sized bits can get into the crevices without damaging the surface of the tile or cracking it due to pressure from the tool. If you use a Dremel tool, be careful around the edges. A 1/16 or 1/8-inch carbide rasp or diamond-coated blades are preferred over the wheels to expedite the removal and lessen the probability of scratching or cracking the surface of the slate tile. The bit can wear down the sides if they are exposed or are not sealed. If the mortar is relatively fresh, less than a week old, a razor blade can whisk away dried mortar in a few simple swipes.
Serious Mortar Removal Tools
When the job of removing dried mortar seems more involved, there are a few tools you should consider using. A wire brush can be used to scrub away dried mortar from the area, but that can take quite some time if you do it by hand. A wire brush attachment for a hand drill cuts the time in half and gives the slate a clean surface in no time. Simply attach the wire brush bit to the end of the drill, clamp it down and remove the mortar gone from the surface and any nooks and crannies that can be problematic when using handheld tools.
Safety Tips & Tricks
When working with tools that will create fine dust particles always wear an appropriate face mask to keep the grit out of your air passage ways. A small workshop vacuum is handy for cleaning up the dust as it collects in piles around the project. The mortar will leave trails of dust for days from the removal process if not tidied up quickly. A damp cloth is ideal for cleaning the surface and giving you a good idea of how far you've come and where you need to focus your efforts.