Hypertufa Mix by Kathy Woolsey
Remember this is not rocket science. Aggregates can be peat moss, coco peat, and perlite or vermiculite. I do not like perlite because it is white. The peat moss or cocoa peat must be sifted through ¼ inch hardware cloth to remove lumps and sticks. Hypertufa made with the classic proportions for mortar (1 part cement: 3 parts aggregate) has a composition of
· 3 parts Type I Portland cement
· 4 parts peat sifted
· 5 parts vermiculite or perlite
For pots 1 parts cement: 3 parts aggregate or 1 quart Cement, 1 ½ qt. Vermiculite 1 ½ qt. Peat 1 qt. water
For stepping stones & bird baths 1 parts cement: 2 parts aggregate 1 part water more or less
To increase strength and longevity, polymer-fibers, liquid acrylic fortifier, and fiberglass fibers may be incorporated into the mixture. Add the fibers to a quart of water and mix thoroughly and add to the mix. Other aggregate such as sand, pebbles, sea glass and crushed oyster shells can be add but they increase the pots weight. Powdered or liquid concrete dyes can be added to the water first to tint the hypertufa to resemble natural rock. Buff, red and brown are the best colors to use. Fibers that protrude from the pot after it is finished can be burned off with a lighter.
Day 2 -Distressing ( making pots look old or wore) After you manage to get your pot out of the mold take a wire brush or file and go over the outside of your pot. This will expose the vermiculite and peat. If you do not do this your pot will look like concrete and not like aged stone.
Carving and drilling holes. The pots are still soft enough to carve with power tools such as angle grinders, dremels and electric drills. Handle with care it will be easy to break until cured. Use a tile cutting bit on the dremel.
Curing – Keep your pot damp covered with plastic in a cool place for about 2 weeks or longer. Occasionally re-wet your pot as it cures. Leave your pot sitting out for a month before planting. The slower concrete dries the stronger it will be.
Recommended reading: Making Concrete Garden Ornaments and Creative Concrete Ornaments in the Garden by Sherri Warner Hunter. My Blog http://cypressgardener.blogspot.com/
We have a 2 day workshops every year in late summer at Cypress Gardens www.cypressgardens.info