Hypertufa is a versatile material that will provide you with many hours of crafting fun.
Your skill level should determine how complicated your mold is. For starters, you can make a nice trough planter from two nesting corrugated cardboard boxes, or two nesting pots.
As you gain skill you can get more creative with molding in sand or making multi-part castings or embellishments like patterns of embedded mosaic tiles or smooth stones.
A good lightweight beginner recipe for small projects uses the classic proportions for mortar. The ratio is 1 part Portland cement : 3 parts aggregate.
The water used is not a cut and dry formula. If you are pouring your hypertufa into a mold, the mix will be thinner—about the consistency of thick pea soup. Large surface solid moldings like garden rocks will take a drier mix, just shy of crumbly.
Hypertufa Tips and Techniques
A bit of advice on ‘solid.’ Find ways to leave hollow space inside. Even as concrete walks have joints for expansion and contraction due to temperature changes, so, too, your hypertufa will need space to do the same.
If it is totally solid, it’s likely that during a freeze/thaw cycle, your work will crack or crumble. Leaving open space also allows the piece to ‘breathe’ during the curing process.
If your creation is a rock, or other large piece, scoop some of the hypertufa out of the middle and put a small empty box, some gallon milk containers or similar in the space.
Again, wrap your space holders in plastic, because you will be removing them, If you are making a ball, use a balloon inside. The idea is to give your hypertufa some room to move.
Planters need drainage holes. The best time to put them in is before the cure. You can use sticks or plastic bottle caps, just make sure you can get them out when the time comes. If you forget to do this, all is not lost. While it’s more difficult to do without spoiling your piece, you can drill holes in once the piece is out of the mold.
You can get concrete dyes to tint your hypertufa for a more natural stone look. Use small amounts and don’t be too thorough in mixing it in. You can even use two complementary colors. Natural stone has gradations in color, and if yours is a little darker in some places and lighter in others, it will be more realistic.