I forgot to mention, my plan is to rent a small power mixer to mis this all up in one batch.

Have you ever worked with hypertufa? This is a big project if this is your first project.

Does what I have stated in paragraph 3 seem relatively accurate? I am sure you found this formula on the internet. There are many combinations using various other ingredients. The one you have will work, I like to use perlite in my hypertufa mix.
Unmold after 24- 36 hrs and work the damp hypertufa with a wire brush, then wet and cover with large garbage bag, keeping moist for a few weeks.
My suggestions would be to start with a small project. Learn to mix. Too much water is not good, too dry a mix will cause the hypertufa to crumble.
Also It will be heavy when you unmold, so make this project right where you plan to use it.
Finally, you dont mention where you live. You should not make hypertufa if the temps go below 50o F , it will not cure properly, resulting in cracks. Good Luck

Plantman, could you call me anytime. 928-580-7971

Steve

Have you made your millstone? I make them from concrete with no problems.
I wouldn't recommend 'tufa for a millstone on a fountain.'Tufa is supposed to absorb water, not sure how well that would work in the long run for a fountain.

Yes, I did. it came out gorgeous, actually better looking than the concrete one I made. It's been running a couple of weeks and is just fine. You can read what I did ad see a pic in the following link:

http://forums2.gardenweb.com/forums/load/gardart/msg102150229927.html

It does not seem to be absorbing water at all and is hard as a rock. I did change my formula slightly: 2cf cement, 3cf vermiculite, 1 cf strained peat moss, 1 gal acrylic fortifier and half bag of polyester reinforcing fibers.

Fantastic!

Hi, I have made mill wheels in both htpertufa and concrete. The hypertufa ones have sat outside my door for about 4 years now and not aproblem with them. The concrete ones (photo attached) are two years old and don't expect to have any problems with these in any way. I use a latex mould inside a wooden former to support them due to the weight and not wanting the latex mould to spread once filled. The wheels are about 2 foot across and about 2 to 3 inches thick. The concrete ones I can turn out the next day but the hypertufa I leave for about 3 days and have damp sacking material on top but again not a problem if left. The main problem is lifting the flaming things and turning them over to remove the mould, getting to old for it.

Sorry photo did not upload so here's hoping it works this time