Concrete tiki for the yard

After reading this thread from Gwen http://www.tikicentral.com/viewtopic.php?topic=45047&forum=18
on building tikis with hypertufa I really wanted to give it a try. Today, I finally did. For those who are interested, here was my process:

I mixed equal parts Portland cement, peat moss and sand using a little bucket for measuring. Then I added water to my wheelbarrow and mixed everything until it was wet. Not super wet, kind of a peanut buttery consistency. I shoveled it into a 8" diameter cardboard form that is sold in the building dept of Lowe's. We've used them to make footings. Before filling I had my husband cut it in half lengthwise and then cut it again from top to bottom so it would be easier to remove later. We taped the seam but it didn't really hold, but the concrete was kind of dry so it ended up not mattering at all.

There were some differences in the recipe from Gwen's instructions and I guess that's why the timing of the project was WAY different! She removed her cardboard after 18 hours. If I had waited that long I would have made a concrete log!!!! After an hour (!) the top was pretty hard and the seam we gaping open so I pulled off the cardboard and it was standing strong.

At the 2 hour 15 min mark I started carving. It carved pretty easily but the concrete is a little crumbly. It gives the piece an aged look, which is cool. It's very dark at the moment but it's going to get lighter as it dries. Too bad, I like it dark.

This was a couple of hours ago. The carving looks better in person, I'll try to get a better pic. The only part I'm a little unhappy with is the teeth. Poor guy lost some due to crumbling! But here's solid proof of how good he looks: my husband just went out to the garage to check him out (I did this all on my own) and he said "looks good, we need to make a bigger one." High praise, indeed!

I think that for the next one we're just going to do a cement and sand mix and eliminate the peat moss. I think that's why it's crumbly. That, and the fact I probably didn't pack the mixture as tightly as I should have in the form.
I don't know if this picture is any better but the carved parts are really quite deep and in person, easy to see.

Hi Lori! I am tickled to see that you did it! Looks good. Yes, any concrete mixture with sand will start to set up in hours- I was just doing one today (see my lamp thread for). Three parts sand to one part portland cement makes a dandy carving mix.
Should you at some point want to do one that dries slowly and gives you time to work in detail, you can try 3 parts vermiculite to one part portland cement. It costs a lot more, because vermiculite is pricey in large quantities, but it is the Rolls Royce of concrete for carving. I wish I could buy it in serious bulk.
If you lash a rope around your tube before pouring in the concrete, it will stay together. Also, if you want to keep the tube from moisture damage so that it can be used more than once, you can make a big tube from plastic sheeting and line your cardboard with that. I have used the same tube repeatedly now.

I like this project and information. I hope you'll post as you set it up in your yard. Terrific, Wendy

Thanks Wendy, I will post pics of the backyard soon. I'm excited that a banana I cut down is coming back up and I replanted another one that over wintered in my kitchen and survived.

Gwen, I bought my portland cement in a 96 lb bag so I have more to use and if I mix it with 3 times as much sand I'll be able to make 2 more tikis! I have a slightly larger form (10") so I'm going to use that next. I think I can use this one again too. Since it set up so quickly the carboard didn't absorb much of the moisture. I'll go check out your other thread to see what you've been up to.

Thanks again for the inspiration to try something new!

Cement ROCKS!

Get it?
:)

Cool thread .... the cardboard is a great idea .... I know the idea of the moss was to make it lighter and I think that is the idea for the vermiculite. Wonder if there are any other fillers that worked as well but are cheaper . You know you can stain cement if you want it darker. I know some folks you some kind of acid etch as well. This is so clever .... Gene

On 2013-05-05 20:42, Gene S Morgan wrote:
Cool thread .... the cardboard is a great idea .... I know the idea of the moss was to make it lighter and I think that is the idea for the vermiculite. Wonder if there are any other fillers that worked as well but are cheaper . You know you can stain cement if you want it darker. I know some folks you some kind of acid etch as well. This is so clever .... Gene

Gene, two inexpensive options are sand and plain potting soil with no added fertilizer. I have done two now using three parts potting soil to one part portland cement. The soil makes a very crumble prone mix, but it looks really cool when it dries, and it is inexpensive and light weight. A sand mix carves wonderfully, but it dries quickly, so you have to move fast. And of course it is quite heavy.

I hope you do more, Lori!

Gwen, I'm definitely planning on doing more concrete tikis.

Gene & LLT, thanks for checking out my project.

I'm going to experiment with different "recipes." For my purposes, weight doesn't really matter. In fact, it gets quite windy at times so if it's heavy at least I won't have to worry about it blowing over. This one is drying darker than I thought it would, I guess that's the peat moss. (YEAH) When we make one out of just sand and cement my husband wants to use concrete colorant but I have used concrete stain in the past so one might get that treatment.

So when it dries, is it still crumbly or is it pretty solid at that point?

It's pretty solid when it dries. It's out in the yard now. It did, however, get lighter now that it's pretty much dried. I'm going to use the liquid concrete colorant for the next time. I'd like it to be black but I think they only sell charcoal. Perhaps after that I'll try a concrete stain that goes on the cured project.