Post #731633 by tikiskip on Mon, Nov 17, 2014 10:49 AM

File this link under best thing....
Here is a link to the whole thing but will also add the recipe for this mix.
Great job on this tiki! take a look.
This idea comes from Wavy_Davy.
http://www.tikicentral.com/viewtopic.php?topic=48404&forum=18&13

To make the hypertufa used here,
I used equal parts of portland cement, peat moss, and perlite. The first big batch had equal amount of sand as well for strength. The additional batches had less sand and I kind of eyeballed it. Probably a little more than half the amount of the other ingredients. I used a big bucket that my pool chlorine came in as my measuring cup. It made it easy to keep the mixes consistent.
Here is a website that I found with some good hypertufa recipes - http://www.artistic-garden.com/hypertufa-recipes/
I used the third one and modified it slightly. I poured all the dry ingredients into a big plastic tub and mixed it up well to incorporate everything. Wear a mask- the dust is nasty. Then I dumped the dry mix in an old wheel barrel and added water to get it to a good consistency. Kind of like making mud pies. You want it wet enough to hold together but not to soupy that it will run. I put on rubber gloves and applied it to the form. The next day - 24 hrs later, you can begin to shape it with rasps, chisels, wire brushes, etc.... It is a joy to carve.

A couple of tips.

• I made a screen out of a piece of wire mesh cloth to sift out the peat moss. It is pretty chunky out of the bag. Using your hands to break up the pieces.
• Since the build required multiple applications of hypertufa, I brushed on concrete adhesive between layers.
• I kept the sculpture wet during the entire process by spraying it with water and keeping it covered in plastic.

To apply the chicken wire to the foam armature I bought a spool of standard heavy gauge craft wire at Home Depot, cut off long pieces and folded them over to make long staples. I just shoved them into the foam around the chicken wire. You can twist the chicken wire to give it shape. I used the wire to crimp and hold the shapes.

I have never worked with hypertufa so I had no idea what the final color would be. It was perfect for the first month or so then it got very light in color. I ended up sponging on some diluted Quikrete concrete stain to get the look I wanted. I called Quikrete and they did not think it would work. So far...so good. We'll see how it makes it through a New England winter.

• Wear gloves when you are doing any shaping after it dries in the first few days. The set up hypertufa carves beautifully and sometimes I would grab a chisel and make a small adjustment here or there. I was too lazy to put on gloves and...the stuff burned off my fingertips.
  I plan on scraping off some lichens from some nearby rocks, mixing it with buttermilk and brushing it on "Moe" I read that this will promote lichen growth to make it look more like a natural stone.

I now have a small MIG welder and I would weld up a wire frame instead of using the foam.

I hope this helps. Good Luck!

Dave