lhtown wrote: You might also be able to make them corrugated or wavy allowing for a bit of bending....If the tank were too large, it seems to me it would start to act more like a flat panel and loose a lot of it's strength particularly when it was empty.
Feral wrote:I use Zeer Pots to cool food with in the summer. Is unsealed ferrocement porous enough to where a ferrocement container could be utilized for a big zeer pot?
If you are really into it, search around for papercrete and let us know if you come up with anything. I can't imagine much reason to mix the two technologies, but they are both fascinating.
I've never worked with Ferro Cement. Suppose one wanted to build domes or barrel vaults. Do you think Ferro Cement might be superior to other types of form work?
The magic of domes and barrel vaults is that a good design might potentially eliminate any tensile load on the material. They can be built from masonry with no reinforcement.
I've done a lot with ferrocement, including vaults, domes, water tanks, buried homes, etc.
One thing I can tell you is that IT IS NOT WATERPROOF. That's right folks, it will leak, or at least, seap. But, depending on the water source, the leaking can actually cure itself, as minerals get deposited in the cracks/pores, and the leak eventually stops.
To make it completely water proof, you need a final coating of Thoroseal or just cement, water, and acrylic.
Very fine sand and/or fly ash helps with the waterproof issue.
Cold joins are the biggest problem with water tanks, you need to reduce them as much as possible.
We've done a lot of ferro-cement, especially for roofs. The Ferro-Cement discussion list mentioned above is a very good resource. We.....
Sugar Mtn Farm
Thanks. What type of cement is it that has the qualities you mention? What type of steel is best to use?
Walter, are you going to build a pop bottle icehouse, as described a few months ago?
We've done a lot of ferrocement. We don't really use many additives, but a few are worth mentioning:
Fly Ash - you can substitute a bit of cement with this. It is super fine and really helps with water penetration. Usually like 5% per mix, though some folks substitute up to 50% of their cement.
Acrylic - this is great for water proofing and really helping with flexibility. Replace up to 50% of the water in a mix for a super sticky, really nice mix. This will adhere well to even old concrete (cold bond).
Mesh - I like layering different sizes of mesh, down to something very fine. Nylon is good, but for the main, base layer galvanized is good. I usually go rebar, remesh, galvanized lathing, then nylon screen.
Neat cement - mix cement, water, and a bit of acrylic to a paint-like consistency. Paint this on as the final coat for exteriors. I like to paint it on after the wall has cured for a few weeks - months. It helps with small cracks and filling voids.
Tools - If you can get a mortar sprayer, it makes things go faster. For mesh, use hog ring clamps and pneumatic pliers. You're armature/mesh eats at least 70% of your time, so get fast at tying things together.