Where would you get aluminium powder? Does it have an industrial application?

Hi Dog
It's my understanding many concrete products redimixes already contain aluminum powder.
I recall reading why they add it but can't remember.
It must be all these Xylene fumes.
I'll be lucky if I can remember my own name.:)

Found this link - scroll right down to the Chemical Foaming section, it gives the proportions.

Here is a link that might be useful: How to use aluminium powder

Thanks Dog

I wonder though what foamed concrete looks like.
I'm imagining something light and porous like sponge might be possible.
I'm wondering how 'lacy' in texture you can get a piece of concrete using a foaming agent. Lava like concrete would be very cool, I could work with that as a finish.

It was also interesting that animal blood is used as a foaming agent.
Yet another use for a dead cat!:)

"Foamed Concrete" is otherwise known as AAC...Autoclaved Aerated Concrete. Been around since 1914 and in use in Europe for 50 years, but, just really getting a foothold in the US in the last 15 or so. One of the world's largest plants is in down in Mexico and I have used some of their products as "fillers" for some of my Faux Bois furniture.

It's mostly made in enormous blocks (about the size of an 18-wheeler trailer), then "sliced" to various sizes or cast into forms for special applications. Basically it is just a micro-aggregate concrete that has powdered aluminum added into the mix which makes it foam up and expand. Only weighs about a fourth of what regular concrete weighs but has similar compression strength. It is, however, very fragile under tension or torsion. You can make like a Kung Fu master and smash a four inch slab in two with ease.

The thing I really like to use it for is sculpting. You can cut it with a regular wood saw and use most wood working tools to shape it. A hand-held grinder or wire brush can whip right through it. Very messy and dusty, but very cool to work with. Check out the link.

Here is a link that might be useful: Aerated Concrete Info

Hi Tango
Any idea where to buy a foaming agent like aluminum powder?
This sounds very entertaining.
I love making bread, so rising concrete might be fun.
I wondering if I can get a surface covered with bubbles that when broken might resemble rough lava.

Based on what I have seen, it is a pretty involed process that requires laboratory level controls in order to avoid disaster. The forming equipment has to withstand the pressures of the expanding 'crete, which from what I was told, are extreme. As for the alumina formulation, I have no idea what it might be. Never looked that far into it.

tufaenough - it gave directions at that link I posted earlier
"Portland cement and lime slurries and mortars are foamed chemically by adding material which causes the evolution of bubbles of gas throughout the mix which may swell to several times its original volume, the expansion occurring after casting. A common method is to add 0.05 - 0.15 mm flake aluminium powder, depending on the pore size required in the proportion of 0.1-to 0.7 percent by weight of Portland cement and lime used in the mix, the expansion within limits, varying directly as to the amount of aluminium. (The use of too much aluminium causes rupture and subsidence of the expanded mass.)"

Then it's steam-cured afterwards to bring it up to full strength.

That's exactly what I want, a bunch of big bubbles on the surface, like bread made with too much yeast.
Some day I'm going to get me some of that aluminum powder. hehe.
Signed FrankenTufa...deep down in the lab.

The aluminium powder seems to be easy enough to buy - I googled and found a supplier immediately. You'd probably have to ask for a tiny sample :)