There is so much information out on the internet about AirCrete but I have found that many times people will show you AirCrete being made and what you can do with it. They never tell you exactly how to make it. It is like cooking in the kitchen there is a recipe for it and it has to be pretty precise or it will not turn out right and it will just be a blob of foam and cement.
We have spent the last few months experimenting with it and working to get the recipe right and for the AirCrete to be right and good enough to build with. As that is the purpose we are using it for is to build domes houses with it. This will be a long post so I may divide it up into two parts. As it will be easier for many of you to catch on too and not get info overload.
If you use a 55-gallon plastic barrel you will notice the gallon marks on the sides of the barrel. You want to use these marks and you will fill the barrel up to the 45-gallon mark on the barrel. If you use the metal barrels you can measure from the bottom of the barrel up to the top and make a mark at 27 inches. Each inch is about 1.7 gallons, so 27x 1.7= 45.9 gallons.
This is the foaming agent we used for making our AirCrete. It is from Rural King. Here is a link for you.
https://www.ruralking.com/drexel-foam-concentrate-gallon-160-1
It is 4 ounces per 5-gallons of water. The foam generator we use has a five-gallon bucket it sits on top of so that is what we use. The foam generator we use is from Domegaia .com. Here is the link!
https://www.domegaia.com/store/p38/Little_Dragon_-_115_volt.html
We also got the mixer we use from them also. Here is that link!
https://www.domegaia.com/store/p26/Foam-Injection_AirCrete_Mixer_-_115_volt.html
I make nothing from Domegaia.com for leaving the links here. This is just where we got ours at! If you want to there are other places to find foam generators at just do a search on google I am sure you will find some more for sale.
We just use a little pancake compressor with this setup and they are cheap if you can catch them on sale at Lowes or Home Depot. it needs to be at least 2.6 SCFM in order for it to work making the foam.
You get started making your foam you want to get a 1-quart container and make sure that the foam you are making weighs about 95 grams per quart. It is between 80-100 grams but we have had the best luck with 95 grams. Start with the pressure on the compressor set at 90 psi, if the foam is too heavy, turn up the air pressure till it weighs right. If it is too light then turn down the air pressure till it is right. It might take some fine tuning but be patient and get it right.
Now for the recipe for making AirCrete now that your foam is weighing out at about 95 grams per quart.
Put 6 1/2 gallons of water in the bottom of the barrel make sure you measure all water out and everything is as close as possible to the exact amounts you will need.
1 bag of Portland Cement goes into the barrel next. Use a mixer and mix this really good and once that is done turn on your foam generator and start adding the foam as you are mixing it with your mixer. Fill the barrel to the 45-gallon mark and make sure all the foam is mixed into the concrete slurry. If you want this mixture to have some more compressive strength mix in a bag of sand with this and it will be a little stronger but also a little heavier. If you want more tensile strength then add some fiber to the mix according to the directions that come with the fiber. We used about a pound to the 45-gallon batch.
Once it is mixed good pour into the forms or containers you want to and let it sit overnight and then you can remove from the molds. It will take about 30 days to fully cure. You can build with it the next day if you are careful. It will cut with regular wood cutting tools.
I will do another post on this subject and give you some ideas on how to make a mortar mix for putting the blocks you make together and also this can be used to coat the outside of whatever you build to add strength and cover the reinforcing fabric on the outside of the structure. Then you can paint it! So stay tuned for the next post on this subject! If you have questions I will try to answer them if you will leave them in the comments below.