foam concrete

[david s]

Re: foam concrete

No, probably not as it's a 50/50 vermicrete, air brew, which would presumably be better than all vermiculite vermicrete. I wouldn't expect the difference to be great, so I won't bother. I'm more interested in it being cheaper, taking up less water and easier to pour and finish.
Perhaps when I make up the next batch I'll try a 5:1 foam, cement and test it's insulating capacity against a regular 5:1 vermicrete sample. Guess we can call it foamcrete.

[david s]

Re: foam concrete

I experimented today by making a 50/50 foam,clay slip mixture. As expected it made a very light mix that had half the specific gravity (density) of normal casting slip. The mix poured beautifully and is drying in the mould as I type. I have high hopes for this stuff and hope to be able to cast and fire a suitable insulating panel for the door. It will be easy to adjust the ratio of foam to clay and therefore the strength and insulating capacity of the panel.

[wotavidone]

Re: foam concrete

It works with clay? that's awesome. It's got pretty good qualities if it can make clay particles do what you want.

[cobblerdave]

Re: foam concrete

Gudday Dave
Interested to know what clay slip is exactly. Now the panel is the insulation for a door right....is it just dried or are you going to fire it like pottery? Could you cast the bolts in the insuated panel so when you bolt your front wooden face on ( i know you like the wood look) the heads remain cool?When I first stared to read this the foam cement sounded a lot like like hebel.....but this clay panel takes it to another place completely. Interested to see where you take this
Regards dave

[david s]

Re: foam concrete

Clay slip is basically water and clay mixed together. If you want to know more look up slip casting. You can pour it into moulds and then fire it to make it permanent, but of course you need access to a kiln.
Having experimented way too much in an effort to create a suitable insulating panel a really good safe solution still eludes me. I'm hoping this could work well. I've tried dense castable both fired and unfired, Hebel, lightweight castable fired. All have failed in the long run as they're either too heavy, don't insulate well enough or they're too weak and abrade too easily.
My current door weighs only 2.4 Kgs and I want to retain the lightweight so it can easily be used one handed.
The finished foamcrete product is essentially the same as Hebel, although it uses a different process. With the foam it is easy to control the density. By using clay it is possible to overcome the problem of Portland cements inability to handle high heat.

[david s]

Re: foam concrete

I cast another foamcrete slab tonight and was more aggressive with the foam. I used 70% foam and 30% perlite to make the 5:1 brew. I mixed it in a 20L bucket using a drill with mixing stirrer.it was ridiculously easy. Laurentius I kept enough to make a sample and may do some tests against a 5:1 standard vermicrete sample to see how they compare as insulators.
I also tried adding foam to clay slip 50/50 by volume and used it to make some slip cast bowls. while worked up to a beautiful consistency, just like a chocolate mousse, poured, set and emptied well, on drying it did not release wel from the mould surface and they also all cracked badly. Shall have to experiment more with it. I'll try to post photos, someone may be able to give advice, particularly potters.

[Laurentius]

Re: foam concrete

What about coating the mould surface with saran wrap or waxed paper, if its a flat surface?

[david s]

Re: foam concrete

No, the clay slip needs to be in direct contact with the plaster mould. The plaster sucks the water out of the clay slip. That is how it dries the casting. A moisture barrier between the two materials won't allow this process. I think the foam makes the material too weak. I might try adding a layer of normal sip first, then the foamed slip and then maybe a final coat of normal slip again so it's like doing a fibreglass foam sandwich. Also might try adding polypropylene fibres to give it mechanical strength.

[david s]

Re: foam concrete

I have been using this foam concrete for a while now and I am convinced of its superiority over perlcrete or vermicrete, it is cheaper, easier to level, requires way less water, faster to dry and a marginally better insulator. I did do some testing of its drying and insulating capacity but my phone line and Internet have been down for over a week and my computer hard drive is being replaced, so limping along with the mobile phone only. I shall post results of my tests when I get reconnected.

[Gulf]

Re: foam concrete

Keep us posted David,
I am someone who has looked into various forms of foamcrete for uses in home insulation to Hypertufa. I'm very interested in your research.

[david s]

Re: foam concrete

Keep us posted David,
I am someone who has looked into various forms of foamcrete for uses in home insulation to Hypertufa. I'm very interested in your research.

You would need an inner and outer mould to do hypertufa as the mix turns out really fluid. It won't work up to a plastic mix. This is one of is drawbacks. It also does not release from the mould surface as easily as normal concrete

[Laurentius]

Re: foam concrete

Hi Dave,

How's it absorbency? Is it more or less that of p-vcrete?

[david s]

Re: foam concrete

No where near as absorbent as vermicrete. It took about half the time to dry compared with vermicrete. I shall test its absorbency by placing the samples in equally measured amounts of water and let you know.

[david s]

Re: foam concrete

I tested the absorption rate of the two samples and was surprised at the results. Each sample is 500 ml in volume and I placed 200 ml of water in a container, then placed the sample in it. The vermicrete sample had absorbed all of the water in 10 mins, while the same test with the foamcrete left 71ml of water (ie it had only absorbed 129 ml) in the same time. It proves that perlcrete takes up more water and at a faster rate and then takes longer to get rid of it. That's a big winner.

[david s]

Re: foam concrete

OK here are the results of my tests on this stuff. I am thoroughly convinced of the superiority of this material. I hope someone else will be keen enough to try it and verify my results.