Existential Angst wrote:
"dadiOH" wrote in message
...
Existential Angst wrote:

Along these lines (and of a previous post), I bought two different
types of grout, sanded and unsanded. Sanded is like a fine mortar
(iiuc), and unsanded is, I presume, very fine particles that don't
quite qualify as sand. The former is for gaps 1/8 to 1/2", the
latter up to 1/8". So that should cover various slate-type, step
repairs, with fine-ish cracks.
Someone had suggested thinset, but the cart was already getting hard
to push....

You should have put back the two bags of grout - neither of which is
what you need - and gotten the thinset.

Well, I didn't open them yet....

The reason I didn't get the thinset was because there were *so many*
versions, I just didn't know which one to get.
They made a lot of pre-mixed thinset in buckets, along with the bags.
What in particular should I look for?

Bear in mind that I have three types of repairs:
missing mortar in a stone wall, on the order of cubic inches of
volume per patch;
spaces in flagstone on top of a stone wall (1/8-1/2" wide), and slate
walkway cracks of about the same;
and very fine cracks around existing slates/mortar in the walkway,
patio, porch.

Will thinset do ALL of this, or just the finer cracks?

I originally suggested thinset because you were having a problem getting
regular mortar to stick on your vertical surfaces. I do too. I used
thinset 2-3 years ago to stucco over a concrete block garden wall to hide
the joints. The wall is about 7' tall by about 50' long. The thickness of
the thinset is probably no more than 1/4". It worked well and there have
been no problems. As explained earlier, I used it to repair some parts of
cap blocks on a garden wall. Pieces had been knocked off by falling limbs
during a hurricane. Those repairs were up to 1 1/2" thick and 1-2" wide.
Length varied from maybe 1" to 7-8". That was at least 5 years ago and
those repairs too are just fine.

Thinset should work fine for all your repairs; the one possible exception is
the very fine cracks in the walkway, patio, porch. Whether or not it will
work for those depends upon how fine and deep they are...if you can get
thinset in them to a reasonable depth it will work just fine.

There is no such thing as pre-mixed thinset. Thinset is a cementatious
material and when water is added the water starts a chemical reaction and
the thinset hardens. It will be hard overnight but will take about a month
to reach maximum strength. The stuff in buckets is an organic paste
material. You don't want it.

Regular type m/n/s mortar has sand in it and has a gritty appearance when
dried. Thinset dries smooth. If you need a gritty appearance in the larger
joints to match better with the existing material, add some sand to the
thinset. Or, do the repair and rub some sand in while the thinset is still
plastic.

As you noted, there are various versions of thinset; they are thinset with
additives. I have never encountered a need for any additive and buy plain
old thinset. At Home Depot, it is called "Custom Blend" and sells for about
$6.00 per 50 pound (down from 60#) bag.

--

dadiOH
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