Another rock background question

[jude]

Has anyone ever made rock backgrounds from hypertufa? It seems to me it would be reasonably simple to dig a shallow pit of the correct size and fill it with hypertufa mix and it would provide a good surface to grow plants on.

Would it dissolve in the water or would the peat make it too acidic?

And are there other drawbacks I haven't thought of?

Cheers

Jude

[jude]

I guess the deafening silence means nobody knows what hypertufa is :lol: :lol:

Its a mixture of cement, sand and peat used to make planter troughs, garden sculptures, planter troughs, water features and fake rocks. It doesn't weigh much and it absorbs water.

Years ago I saw a gardening programme where they dug a hole, poured the mixture in and when it was set pulled it out again - instant fake rock.

It seems to me it would be easy to pour a fake background using this, if you used a shallow hole, the lumps and bumps would become caves and overhangs and it could be made in separate pieces - which brings me back to my original questions - would it crumble in the water, would it make the water too acid or alkaline?

Cheers

Jude

[alanmin4304]

If it absorbs water it would be likely to leach from the cement and peat. This need not be a problem as gold fish live in concrete ponds and many people add peat to aquariums. It would be a matter of getting the balance right. I would think fibreglass would be a good material. Impervious and easily cleaned if you used food grade materials.

[Ira]

The acidity of the peat would counteract the alkalinity of the cement, to some amount anyway. Go give it a try and report back, Jude.

[jude]

I was thinking that Ira, and I am tempted to trial it. It seems such a simple way of making a wall.

Apparently you can lay a fine mesh through it to give it strength so that might stop it crumbling.

Cheers

Jude

[jude]

Hey Ira

I've just been sitting here watching your aeroplane take off over and over again - its hypnotic but I think the Wright brothers flew further :lol: :lol: :lol: :lol: :lol:

[Ira]

Perhaps, but the real question is, could the Wright brothers have taken off from a conveyer belt?

[jude]

:lol: :lol: :lol: :lol: :lol:

[Hazara]

Any updates? I just found this thread and looked into hypertufa... it looks so simple even I should have limited success with it!!!

Would be able to make some really cool features for my amazon bowfromt tank with it and it has a lot of other possibilities as well!

The only issue I can see is the concrete which would soften(?) the water. But I have no idea by how much. I love the idea of making little peat caves and then blasting the peat out.

From http://www.efildoog-nz.com/hypertufa.htm

How to make your Hypertufa tub: You will need the following:-


Materials and Tool list:


1. For a square or oblong tub you will need two cartons, one of them with smaller overall dimensions by at least 5 or 6 cm. Place the smaller carton inside the larger. There should be a gap of 5 or 6 cm between the walls on all sides. These cartons are your moulds. For round containers try different size plastic bags, old plastic basins, or buckets.


2. Concrete blocks, bricks or short lengths of heavy timber to fit flush against the outsides of the outer carton for support. This stops the sides bowing out under the weight of the material. For the inside of the container use any spare sand, soil, potting mix (anything bulky) to stop the inside carton caving in. Fill up the inside carton progressively as the walls are built up. If you are using plastic bags for moulds, place 4cm wide adhesive packaging tape around the outside to prevent bowing.


3. Pieces of broom handle, branch or 25mm plastic pipe about 5cm long are used for drainage holes. These can be carefully removed later on. One or two holes are sufficient for small pots, but for larger tubs and troughs at least 4 drainage holes are needed.


4. The ingredients in proportion by volume - 2 parts peat, 1 part sharp river sand, moderately fine, but not beach sand (because of salt and it is too fine) 1 part cement.


5. Tools - Plastic Sheet 1.5 x 1.5 metres, Wheelbarrow (optional), Trowel or spade, Rubber gloves, Tamping stick, 50 x 50mm about .5 metre long, Wire brush, Old hearth brush, Water container or hose. Well now we have it altogether, let's start!


INSTRUCTIONS


Lay the piece of plastic sheet on the garage floor. Place the large carton in the middle of it. 


Place the concrete blocks against the outside of carton. Mix the ingredients in the wheelbarrow or on the floor. Quantity depends on the size of the envisaged container (use your judgement). After mixing the dry ingredients thoroughly add sufficient water to make a sticky stiff mix - not runny but about mud-pie consistency, if you can remember back that far. Now stand the drainage plugs upright on the bottom of the carton and place a layer of the mix on the base and tamp it down giving special attention to the corners and around the drainage plugs. Aim for a thickness of 5cm for small to medium size tubs.


Take your smaller carton and place it on the layer of mix in the bottom of the larger carton. Make sure it is equally spaced on all sides. Then one quarter fill it with sand or whatever you have. This will stop the inside bowing in and the carton floating up. Now fill up the wall space between the cartons. Use the tamping stick to work it into the corners as you go to get the air bubbles out. Make sure you tamp the outside walls well. Keep building up the sides with mix, adding sand to the inside carton for support until you have reached the desired height. Leave it and don't come back for at least 24

hours.

Finishing: Next morning dash out and have a look at your handiwork. Yuck! Wet cartons. But that's just what you want. First, scoop out the sand from the inside carton. Then CAREFULLY peel off the inside wet cardboard and discard. Now the outside. Remove the concrete blocks and carefully finish peeling away the outside carton but don't worry about the bottom.


DON'T TRY TO MOVE OR TIP THE CONTAINER AT THIS STAGE - YOU WILL LOSE THE LOT !


Now the tricky bit. You will notice that the walls are rather smooth, in fact just like dark wet boxed concrete. This is not on. We want the walls to look aged and weather worn. This is what we do. Using a wire brush or a special scraper (see below) we very carefully roughen the sides, top and inside rim. I prefer to round off the corners and edges as well. Don't worry about a few nicks and scratches and small holes. These help to give it a natural look. You may wish to carefully scratch in your own design or special texture. Having shaped the outside to your requirements, gently give it a good brush with a hearth brush.


The container should be left for at least a week to allow it to cure and set hard. Give it a light sprinkling with water initially 3 hours after moulding and therafter every couple of days to assist the curing process. It is most unwise to lift it until it's entirely set, but if you have to shift it only do so by sliding or dragging it across the floor by means of the plastic sheeting. The mix left over can be used for stands for the containers. Either press it into pottles or plant pots or roll it into flattened balls. Using builders' adhesive these can be attached to the container base as feet at a later stage.


SO, THERE WE HAVE IT !

[jude]

I haven't tried it yet but it's on my list of things I want to do. I think the concrete would harden the water rather than soften it, but hopefully the peat would counteract that.

The instructions I read suggested using a shallow wooden tray. lined with plastic and filled with sand. You then made lumps where you wanted caves, and hollows where you wanted protrusions, and poured the mix over that. When it was set you could hose off the sand. The site also suggested you could dig a shallow trench in the garden and use that as a mold.

Cheers

Jude