Let me qualify this by saying I have never used mortar as a grout so I have no experience BUT! (hah) I can't see anything to stop you from using a concrete colorant to get where you want to go, However the charcoal colorant for concrete will only get you a darker shade of grey, you could then use black Tintsall to go darker.. so that's my 2 cents worth..

Checking in after all the T Day company just left. My 1 cent in this is: I've used mortar as grout several times. I've used 1/2 mortar and 1/2 grout as grout a few times and that's a nice mixture. When I used that method I mixed half black and half pearl gray for a nice charcoal. Don't know your reason for using total mortar for grout, but IF I were to do that again, I'd use a black powdered colorant in the mixture. In all my experiments, I've become comfortable w/just using plain black grout. It is perfectly safe w/the elements.

Thanks, Nice and Slow. My reason for planning to use mortar as grout was, I thought that's what I needed to do because of it being outside in the elements. But if I can use plain black grout, then that's what I'll do! Yay! I have a bunch on hand already because of the space mosaic. Thanks so much for your comments.

Or you could go with that epoxy grout as an option

I've seen another artist who uses mortar for grout, and that's why I tried it. It's very messy and gooey. When I used half mortar and half grout, it dries too quickly to clean up large projects. Just plain cement-based sanded grout is perfectly safe for outdoor projects, and it's easier to apply than the mortar. Like you, SILVA, I use Mapei's products and love them. Remember, if anyone has questions re this subject, Mapei's 800 number w/get you a nice customer service person to answer any and all questions.

I use grout on my outdoor items and it gets pretty cold here -30 @ times and it's all still together!!!

I use grout on all my out door thing some have been out for years.no prob..

You guys know me and my Black Grout!lol! Luv the stuff and buy the mapei outdoor now for all of it. Soooo, Silvamae, where's the WIP pics????heh heh! I want some EyeCandy girl!!!!ha!

Will post pics tomorrow. Tried to get some good pics just now and there's too much glare on the sign and it's too heavy for me to move. We just cut out the Wedi today and we used an old, old sabre saw from Montgomery Wards and it worked like a charm. Had to piece the sign together out of 3 3'x5' pieces of Wedi.

I was gone all morning so there was a glare from the afternoon sun again today by the time I got out there, but here's a picture of the sign, and the second picture is of the Wedi with my tissue paper design on top. The sign will be done in black and white stained glass, and I will probably use white grout some places and black grout other places, haven't decided yet. May use black only.

Oh wow that will be so cool!!! I'me going to start a sign for my husband..for his golfing hill.. He calls it Fenton Hill Park!!! Thought it wud be cute to have a sign.

ooo that's a cool logo

WOW - that'll be soooooooome project. Looks huuuuuuge.