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Xist 12-09-2017 08:10 PM

So, the other day I took a red pill on housing, freebeard told me about Aircrete, and I took a bigger red pill.

What is Aircrete?

Cement and soap foam, together at last.


AirCrete is a lightweight non-toxic masonry material that is easy and inexpensive to make yourself with Little Dragon. It is waterproof, fireproof, and insect proof. It offers good thermal and acoustic insulation. It will not rot, warp, or corrode. Unlike concrete which is hard, heavy, cold and difficult to work with, AirCrete is easy to work with. It dries overnight and can be cut, carved, drilled and shaped with wood-working tools. It accepts nails and screws and is easily repaired. It had good compressive strength to make excellent foundations, subfloors, building blocks, poured walls, domes or whatever. It can be molded or formed into practically any shape. AirCrete can cut cost of conventional methods of construction by a factor of 10 for several reasons.
What is AirCrete?

I have had all kinds of questions and it seems like nobody has answers for many of them, or one answer leads to more questions.

First of all, why is it Aircrete if it is cement and foam? Don't they know the difference between cement and concrete? Can I build a house out of it? Can I build a snowman? That same pages says "Just one liter of dish detergent with 10 gals of water make enough foam to produce about 2 cubic meters or 70 cubic feet of AC. The foam expands the volume of cement by a factor of 5 - 7. It eliminates the need for aggregates, gravel, sand, or rock."

A ratio of 1 liter of dish soap to 10 gallons of water.
Who mixes units? How does soap foam replace gravel, etc.?
So, a ratio of 1.05669 : 40. Cool.

Dome Gaia sells a foam machine for the bargain-basement price of $500, although they will ship you the kit for $360, and plans for $39, but they say it will probably cost you more to source the parts yourself. Little Dragon - 115 volt This guy sells plans for $8 and says the parts will cost $30, but apparently people complain it cost them over a hundred. They will send you the parts for $80, or the complete unit for $125

I am not sure about the Little Dragon, but the Etsy one requires an air compressor, which is fine if you have one.

I firmly believe in using the proper tools, but I am not spending hundreds of dollars out of curiosity.

What about...

at least for proof of concept?

It says to take a 55-gallon drum, add a crazy-heavy bag of cement (94 pounds. Weird number!), seven gallons of water, and enough foam to make 45 gallons.

So... how much foam?

Ninety-four pounds of cement is one cubic foot, which is 7.48 gallons, so a ratio of 1.06864564: 1 of cement to concrete.

Right, so what is the total volume?

How much shaving cream is in a can? Nobody knows.

I bought a 12-ounce can from the dollar store and got just over a gallon from it. I mixed 28 ounces of cement and 30 ounces of water, which yielded about 48 ounces of concrete.

7:48: 45 is about 1: 6, which would have required 288 ounces of foam, 2.25 gallons--two cans would not have been enough!

I bought some plastic toolboxes from the dollar store, 4.5 x 11 x 3 inches. Each can made about 1.25 shavingcrete bricks, although with 2.25 cans of shaving cream it would have been 2.8 bricks.

The toolbox has been in the bathroom with the heater on for hours. I do not have any idea how long it will take to harden. It is taking forever!

oil pan 4 12-09-2017 08:21 PM

94lb of Portland cement is 1 cubic foot.
That way if you are like me and mixing up ballistic concrete you are looking for about a 1:1:2 mix or 1 part cement, 1 sand 2 large aggregate you know how much stuff to buy or how much concrete I can make with the stuff I have and how much it will cost.
Furthermore how much water to use. The more water you use the weaker you concrete will be.

The aircrete I was looking at not too long ago mixed soapy water with Portland cement.

freebeard 12-09-2017 08:45 PM


I bought a 12-ounce can from the dollar store...

I bought some plastic toolboxes from the dollar store...
Good for you. I thought this would be about wood shavings.

What I took away from the videos that I watched was that it gets crumbly if the foam bubbles are too large. IIRC somewhere in the 5-10 micron range(?). Using shaving cream is a good kludge, maybe you can find out about what size the bubbles are.

Curing time isn't going to be hours. Concrete is stiff enough to walk in on 48 hours and continues to gain strength for a month. Eventually you will have some test samples. :thumbup:

Earlier today I was reading about carbon neutral/negative concrete:

The material that built the modern world is also destroying it. Here’s a fix

Yesterday it was:

When AAC is mixed and cast in forms, several chemical reactions take place that give AAC its light weight (20% of the weight of concrete) and thermal properties. Aluminum powder reacts with calcium hydroxide and water to form hydrogen. The hydrogen gas foams and doubles the volume of the raw mix creating gas bubbles up to 3mm (⅛ inch) in diameter. At the end of the foaming process, the hydrogen escapes into the atmosphere and is replaced by air.

rmay635703 12-09-2017 09:38 PM

A similar effect can be accomplished by making cinderblocks

Aircrete sounds weak and water permeable but who knows maybe it’s weight to strength remains fair?

Further cement with bubbles won’t insulate well, the cement conducts so well heat will just bridge around the bubbles,

Maybe a small increase in insulation r value similar to paper concrete made from paper mill tailings?

oil pan 4 12-09-2017 09:54 PM

You can always coat the concrete products to make them better in some way. Say epoxy coating them.

freebeard 12-09-2017 11:52 PM


Aircrete sounds weak and water permeable but who knows maybe it’s weight to strength remains fair?

Further cement with bubbles won’t insulate well, the cement conducts so well heat will just bridge around the bubbles,
Concrete is weak and water permeable. Depending on the mix, the ancient Romans had it down. Modern concrete relies on steel reinforcing, which rusts with water penetration leading to spalling.

You can find Youtube videos of someone holding a block of aircrete and holding a blowtorch on the other side. It's like the Space Shuttle's tiles.

Let's imagine for a moment. An telescopic robot arm at the center of a circular building line, with a 3D print head at the wrist. Two print nozzles; one is aircrete — as stiff a mix as can be pumped through the nozzle, the other a mortar mix with fiberglass strands or sand, with or without epoxy hardeners mixed at the nozzle.

Depending on the degrees of freedom available to the arm, the form would be approximately hemispherical.

I don't get why people don't go for this stuff. :confused:

Xist 12-10-2017 12:29 AM

I'm a people!


By the way, I was trying to figure out how to make concrete from facial hair, but I realized I needed to cut it off first.

Pity. Lappy is not letting me attach the picture of Aircrete floating in water.


Build a bridge out of it!


Dome Gaia says it is rated to 300 PSI, but concrete is far stronger than that.

oil pan 4 12-10-2017 08:41 AM

My ballistic concrete was around 3,600psi at 28 days according to my Schmidt hammer tester.
Which was almost identical to commercial "5000psi concrete".

freebeard 12-10-2017 04:27 PM

Often I wonder why Saving@Home or Eco-Renovator don't get more attention.

Just like cars need glass and rubber, a house needs more than a weather shell. Here are two things I've seen lately, one high- and one low-tech: power advances possible with new 'double-glazing' device Channel Tesla & Einstein To Invent New Double-Glazed Solar Panel

Bucky Fuller proposed triangular vacuum glazing in his 1928 Dymaxion house. It turns out Argon gas is better.
THE DYMAXION HOUSE: Dymaxion Developments

Then there is what you can do with plane trees and stainless steel screws.

Compared to the massive steel scaffolding they use with their in-the-box thinking, one could make an edge vertex half-icosahedron with planters on two full height tripods and two half height posts.

[place to add a picture when I find it]

samwichse 12-11-2017 02:57 PM

Or maybe just add a bag of this to 1cuft of portland cement?

First porosity material that popped into my head, and it looks like it's a thing:
SCHUNDLER COMPANY--Perlite Insulating Concrete

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