Hey dchall-

I don't think you will want to make a container meant to hold water out of hypertufa. The organic aggregate will eventually rot leaving you with a container that leaks slowly or very fast, depending on your mix.

Are you building this water pot in place or transporting it? If you're building in place, then it might not matter how heavy it is and you can use regular old concrete mixes which will not leak once cured.

If you plan to build in one place and move the finished object into place, then I will defer to others as to their opinions, but I know that both perlite and vermiculite are susceptible to moisture to some degree. Whether they would give you a water-tight end product, I just don't know.

This link is to a type of water tank that you might want to emulate. Keep in mind that they had to use a crane-like technique to get the parts into place, but it's pretty elegant looking, IMHO. www.rdic.org/balltankinfo.htm

This link is to a woman who built a concrete water tank on her property. www.backwoodshome.com/articles2/ainsworth101.html

I hope this helps!

Jo

Well it is the shape I want, not the medium, and the effectiveness of the barrel is not all that important. I expect it to overflow and will design the water escape route away from the house. The purpose of the jar (or barrel) is just to break the fall of the water. But I don't want the jar to dissolve on me.

It will be poured in place.

If I went with concrete I guess I would still use a PVC core. Unless someone has better thoughts on it.

dchall, You would have the best chance of it holding up made from concrete. The PVC core is a good idea. Or what about a large plastic trash can for a wider opening instead of PVC? You could attach wire lathe or chicken wire to flesh out the shape. With a wider opening you'd be sure that the water would hit it but would it attract kids and critters so be considered a hazard? I do remember some pics that someone posted of enormous pots/urns (5 or 6 feet tall) from Texas or New Mexico, I think. Keep us posted. Billie

I would make one like your picture in two halves using forms made from boat dock styrafoam floatation. The mold can be made by shaping it with a knife or saw, then rubbed or sanded to round off the high spots. Cover the mold with dry cleaner bag plastic. Always plan on how the form will be removed. Make the bottom half upside down over the form. Make the top right side up. After removing from the mold mate the two halves together by bonding with soupy mix. Smooth the joint. It will help if the two pieces are cured only enought to be removed from the molds.

I made a big stone jar once by putting 'tufa directly over a wicker vase from Goodwill. It's about two feet tall. It was a pretty iffy structure to build a jar over but it's held up well.
If I were to do it again, I'd put lathe over the basket shape and form it to fit with needle-nose pliers. It would supply more strength, especially when the basket eventually rotted away.

I'm pretty sure Dena made a tall vase over lathe and put it on a horizontal pole while she was working on it so she could turn it to cover all the sides. Maybe she'll see this discussion and have something to add.

Deb

These are great ideas. I'm glad I asked. And the thought about attracting kids and critters is an important consideration I had not had. Hmmmm... Mosquitoes are another factor I had left out of this project. The jar might not work at all. Our mosquito season runs from now through November. Now I'm thinking 'flagstone' or something flat that I don't have to tend for critters.