wrote:

On Wednesday, October 3, 2012 4:41:46 PM UTC-7, Existential Angst wrote:

Looking to patch up my stone walls, between stones. Was at
HD today, must be a half-dozen or more types of mortar -- or,
iiuc, "sandmix". Is there any type/brand particularly good
for patching stone walls? Any particular prep? I figger I'll
clean out the patch areas with a garden hose, etc. How to get
the stuff on/in the vertical wall face is the next challenge.....
Any tips? 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.

Mortar is usually sold in grades M (strongest), S, and N (weakest), and building walls generally need type S.

Leave that to drive the point home--

-snip-

I found it was easier to fill the joints from a grout bag (like a cake decorating bag, only
much bigger and made of naugahyde vinyl upholstery) rather than pushing it in with a
trowel from a hawk, especially vertical joints. Most grout bags are sold with a steel nozzle,
but its opening is so small the mortar won't flow out, so I use the bag without it. Finish
the joints the normal way, with a striker or trowel tip.

I like the grout bag, too.

If there isn't much to do-- I like this stuff, too.
http://kk.org/cooltools/archives/4031

Quikrete mortar in a caulk tube. It was the nuts when I repointed
my chimneys 6 years ago. I haven't gone up there, since, But I've
checked it out from the ground with binoculars and you can't tell what
is patch and what is original. [I used 10-15 tubes on 2 chimneys-.]

If you've got a huge job you might look at pointing guns- I think they
run 50-100 bucks, but are easier to handle than a mortar bag.

Jim