Masonry Magazine April 2004 Page. 47
Tinting a Mortar
VERY FINE PARTICLES, like cements and pigments, have the greatest effect on mortar color. Not all cements have the same color; there will be variations in shade depending on raw materials and manufacturing processes. White cements - Portland or masonry-lead to the truest mortar colors, especially for lighter shades or pastels.
Pigments for mortars need to be compatible with cement and lime and be color-fast and stable. Natural or synthetic mineral oxides generally meet these criteria. Pre-mixed colored cement products are preferable, but if blending cements and pigments on-site is necessary, pre-weighed pigment packages are available. Job site blending is not as easy as using premixed materials, but yields excellent results as long as strict attention is paid to consistent proportioning.
Sand, too, has the ability to lend color to a mortar, especially as the cement paste wears away and exposes the sand aggregates. When color is important, you can use the various available cements and sands in your area to make comparative mortar samples.
Getting the Best Color
THERE ARE SEVERAL practices that improve color uniformity. Using the same materials throughout a project is ideal. If there is adequate storage on site, all of the sand can be delivered ahead of time. Cement should be from one source, too, and if bags are used, they have to be protected from moisture: Store them on top of pallets and cover them with tarps.
Field procedures affect mortar color. Accurate batching and thorough mixing lead to consistent color. A box of known unit volume can be used to calibrate sand additions to the mixer (such as shovel counts) and as a periodic check for workers to be sure they are adding the right amount of sand. Controlling the sand addition is a simple check on proportions.
Mortar should always be considered in designing a wall for maximum architectural impact.
Ambient temperature and humidity conditions affect mortar workability. Add enough water to get constant consistency from batch to batch. Small water adjustments should have negligible effect on mortar color. Mix only as much mortar as can be used in a reasonable period of time. Cover the mortar to minimize evaporation and retain workability. Re-tempering colored mortars should be avoided.
Normally, mixing times from three to five minutes are adequate once all ingredients are in the mixer. With colored mortars, the longer mixing times assure thorough blending and give better results.
Tooling and Curing
LIKE OTHER ASPECTS of colored mortars, timing the tooling of joints should be consistent over the entire wall surface. Early joint finishing generally The Voice of the Mason Contractor
THE "POST"
SPEED LEAD
Quick set up. Quick take down. Fewer parts. One bracket assembly. Ideal for all applications of brick veneering. Inside, outside, quion, and angled comers. Invented and patented by a bricklayer.
For information write or just call (800) 525-8287
Marv Post Enterprises Inc. 2858 Sibley Hills Drive Eagan, MN 55121
SOLAR POWERED
NO WIRING Allows installation ANYWHERE
Automatically turns on and off at dusk and dawn
Shines all night long (up to 12 hours) with one full charge
Completely waterproof
Can be driven without damage
Colors Available: amber, green, red, white, orange
Sizes Available: 8" x 8"x 2 3/8" and 4" x 8"x 2 3/8"
ALL CONSTRUCTION SUPPLY
TOLL FREE 877-432-7387
April 2004
Masonry 45