Heathcliff wrote:
On Dec 3, 1:54 pm, "RogerT" wrote:
blueman wrote:

The job is *real* small - basically we have an old millstone out
front as a stepping stone to our front porch (it looks really nice).

Whoever put in the millstone, filled the old central hole with
concrete
that matches the stone itself pretty well.
HOWEVER, the fill is about 1/4 -1/8 inch short of the surface, so
water still pools there forming ice in the winter which is
dangerous...

I would like to level it off with a thin veneer of new matching
concrete (erring if anything on the side of being slightly proud of
the
surrounding surface).

I plan to use a latex binder instead of water in the mix so it will
bind better to the old stone and concrete.

I probably only need maybe 8-16 ounces total to make the patch so
buying pounds of colorant seems like a waste...

For such a small batch I didn't want to starty buying and mixing up
my own batch of concrete. So my plan was to use quickrete filtered
of any of the stones plus maybe a little mortar (all of which I
have hanging around) and add a small biit of something to make it
look dirtier.

I just need to know what something to use...

Perhaps I would be best off adding some aquarium sand to the mortar
mix
I currently have.

Any suggestions?

Interesting question. Since the space is only about 1/4 to 1/8 inch
thick, I wonder how well whatever you put in there will stay in
place. Maybe the suggestion about using tile grout will work, or
maybe using concrete patch that they sell at Home Depot etc. will be
better than mortar or regular concrete.

I did a Google search of online images for millstones. To do the same
search, go tohttp://images.google.com/imghp?hl=enand type in
millstone for the search. Do any of those images look similar to the
millstone that you have?

Whatever you use to fill the patched area, would it be possible to
grind off part of the millstone in a hidden area and spread that on
top to try to do the match? Or, maybe drill some holes in the center
part to help hold the patch and the use the drill dust on top of the
patch to try to match the color?

I like the drilling or grinding idea - extra work but that sounds like
how an architect would approach it. One other thing: if it was me I
would look at using thinset mortar mix - the stuff you set tile with.
It comes in various colors, seems to be happy being in a thin layer,
and it's sticky. I would favor that over grout. -- H

thinset is very soft and would wear away. grout is stronger. the suggestion
above was to use grout to color concrete, not use grout by itself.