I bought a Carbide Grout Scriber tool thing from Wilkinsons today--that is ok, works well.
Went along with Brian C's nail in a piece of wood--that was ok too. Either way, the Carbide Scribe Tool or the piece of wood with a nail is easy(ish) going up and down the wall ... side-2-side is hard work.
How deep do I need to go? My tiles are about 6mm thick.
I guess the Adhesive would be 2 or 3mm thick. So do I need to scrap away all the Grout back down to the wall or will just taking off say 5mm of Grout be ok and would the new Grout bond ok?
i hate removing grout and have found that using a grout scraper just gets all clogged up too quickly, i just stick to using a stanley knife with a new blade, i do have to change the blade around a couple of times depending on how much grout is to be removed, i use a decent stainless steel stanley and you can get the blades cheap.
I purchased a Plasplugs (pro-series) Tile Scribe which has a Tungsten Carbide tip .. the "main" use for this is to scribe ceramic tiles up to 6.5mm but have found this a great tool for removing grout.
I've used this for more than 2 hours today and after all the work, the tip is still as-new! I gently 'scribe' the Grout up and down and for the horizontal I go from left to right to left .. and so on. After a few light scribes apply more pressure and this takes the Grout clean out.
I'm getting there!
But, I do have one question I'd like to ask you 'professionals' on here ...
My tiles are about 6mm thick and I guess the Tile Adhesive would have been applied approx. 2-3mm thick. So that's 8-9mm of Grout in depth approx?
How much Grout do I need to remove before applying the new Grout? All of it (i.e. right back to the wall) or would taking away say 5mm of Grout be ok?