@zander Zander thanks for the info. This will have significant effect on my bottom line and let me build more. I greatly appreciate those of you who are posting actual experience. I hope to be joining you soon with detailed documentation of my build experience.

@zander said in aircrete vs. ferrocement:

We walk on our domes frequently.

Interested in the block thickness. You walk often on 3.5 thick blocks. I presume at the density DomeGaia publishes i. e. 19lbs cubic foot. My dome will be 21foot dia internal and I was thinking I needed 5" block thickness. If I can go 3.5-4 that would certainly help out in material cost. Has anyone figured out the ratio of needed block thickness to dome diameter?

Zander, this is why I am a member of this forum. Bright creative inventive people come up with great ideas. I have wondered if the amount of Portland which did not get mixed up in the bottom of my drum had a major effect on my first bath failing. It was maybe 2-3 cups of Portland not mixed. I think that may well have been enough to throw the pour off.
I will be making the famous Zander whisk before mixing my next batch.
Thanks for the clever idea.

I will be documenting and posting my build and experiences. I want this tech to spread. We are all relatively new to this and we are all learning. I will be soaking up all knowledge and experiences I can get.

My thought on this is to run the conduit along thew base perimeter of the arch. It would be covered by the internal finish or a small accessible base plate. It would be the simplest and most cost effective I think. Less excavating in the floor.

Wish you luck Brian. I am disappointed so far with my results using shampoo and dish soaps. You can see my results below.
I am hoping the data will assist others who have been successful to critic my findings and help me out. I know others have done this repeatedly. I just don't know what I am doing wrong.

@anthonydjones Note in the excel pic. the Jar used is the constant weight of 14oz and the numbers to the left are the weights on my digital scale. The spreadsheet subtracts that constant from the weights and produces the actual foam weight in oz per quart.

I made my first full batch pour of 94lbs Portland type I/II and my 30oz Suave/5galbuck foam solution which had given me foam denser than the 3oz Domegaia recommends. It did not turn out well but almost completely collapsed. Am I using the wrong Portland? I later tested my rain water I used and found it to be between 6 and 6.5 pH.
it seems the variables is Portland solution and water. I am using the solution mix which has worked for most who have tried it and presumably good Portland. The only thing left is the water unless someone knows other factors like water/environment temp, humidity etc

@Martin10 My thoughts on how to do this.

1. Slide two diameter EMT lengths one inside the other and screw them together like a set screw.
2. attach a threaded rod to one end of your compass with a couple of nuts so you can adjust for each course. The added distance should not be much and this should work great. You just have to determine how long that threaded rod needs to be. Or you could just add a length of EMT to the compass when your threaded rod is too short. EMT is cheaper than rod.
   Things may change in real practice and I will of course share all findings with the tribe.

@Martin10 This explains how the compass works. He is dimonstrating how to make the conical shape. It's used on sand bags but the same thing can be used on Arcrete blocks.
iVideo](https://www.youtube.com/watch?v=NFctQvmfsys)
The compass explanation starts at the 15:10 mark in the video.