Mortar is composed of portland cement for bonding, hydrated lime for workability,
and sand for strength and bulk. Mix only as much mortar as you can use in 1 hour;
after that the mortar becomes unworkable.
For a small job, it is easiest to buy ready-mixed mortar, which comes in packages
of 10 to 80 pounds. Mix it with water according to the directions on the package.
For larger jobs, such as building a brick barbecue. it is less expensive to
buy masonry cement, which contains only the cement and the lime. Mix it with clean
builder’s sand in a ratio of 1 part masonry cement to 3 parts sand. You can also
buy portland cement, hydrated lime, and sand separately; mix them in a ratio of 1:1:6.
Masonry cement comes in a variety of colors; if you like, buy pigments for coloring any mortar.
Making the mix
To prepare mortar, measure out the materials by the pail or shovelful in a wheelbarrow
or on a mixing board made of scrap plywood with planks nailed to its sides. For small
batches, you can use any shallow container, even a garbage-can top.
Blend the dry materials thoroughly, with a shovel, trowel, or hoe; then gradually
add water, working the mix until it is plastic and smooth. Workable mortar should
spread easily, cling to a vertical surface without smearing or dropping, and stay in
place (not flow) while stones or bricks are being placed.
To test the mortar, make a furrow across it. If the furrow holds its shape, the mortar
is the right consistency. If the sides of the furrow slump, the mortar is too wet;
add more dry materials to stiffen it. If the mortar sticks tenaciously to the implement,
the mix is too dry; add water.
Caution: Mortar is a caustic. Wear goggles, waterproof gloves, long pants, and a
long-sleeved shirt. Promptly wash splatters off your skin. Rinse clothing when you
finish working. If mortar gets in an eye, flush with clear water and call a doctor.