Anyone tested with foam density?
Posts made by chuckj
Ratios And What they Affect
I have my foamer down well and have numerous blocks, planters etc made. To me they are fragile, not brittle really, just fragile. I am using .64 gal water and 9.4lbs cement in 5 gallon bucket and fill it till full with 88g / qt foam made w Drexel and water. I see that stucco, when applied to the outside, makes a tremendous difference.
My question is in the ratios.
what does heavier foam density (100 or 120) vs lighter foam density (with all other ratios the same) affect? Does heavier foam / qt create stronger or less strong bricks?
what does water ratio affect? Going to 5 gal water per 94lb bag or going to 9 gallon per 94lb bag. Is the 5gal stronger or the 9 gal stronger?
This site (https://naturalbuildingcollective.wordpress.com/tag/compressive-strength/) provides field tests to identify MPa for compression and tensile on adobe bricks. I would guess these field tests would work on these block types too!? They say 1.3Mpa or 190psi compession and 1.8 tensile is strong enough to build with.
I realize I could keep doing tests to figure out my answers above as to what affects what but thought I would ask and see if someone has already done that.
RE: Average Cost Per Sqft
There are too many variables to reply to I think. Wall thickness for instance, wall height etc. The question you ask is all about volume.
Here is something, 94lbs if cement yields a 50 gallon drum, roughly 7 cubic feet of material. A 94lb bag is say $11. Assuming water is free and you just need foam, the foaming agent is $45 for 160 gallons or roughly .30/gallon. I am not 100 percent sure but let’s say it takes 3 gallons water/foam for 50 gallon drum, so 3 gallons at .30 per gallon and we need 3 so we can round up and say $1 per barrel in foam. So we are at $12 for 7 cu feet of material.
You can figure the rest out from there. Just multiply total length of walls and total height of walls and total width of walls to get volume used and use numbers above to get cost. This doesn’t give outside coating cost.
Say a 100 sq ft room 10x10 has 40 linear feet of wall, roughly. 8’ high gives 320sq ft of wall space say 6” thick is 160 cubic feet of wall volume. I think my math is right here. So 160 cu feet divided by 7 cu ft per barrel is 23 or so unique 50 gallon barrels of aircrete. So 23 barrels of product * 12 a barrel is $275 in cost or so.
So $2.75 per ft not counting a roof. $5 a ft for 1’ thick walls.
I did all this this way cause I don’t know nor want to look up the math for a volume of a sphere but you get the point. It’s cheap. :) i hope this helps.
RE: Aircrete is collapsing
@HandyDan hi. Yea I was wondering if I was using the wrong mix. I am using concret mix. 10.5lb bag of quickrete. So it is a mix of cement and aggregate. Wrong stuff I guess. No wonder. I have anothe idea too. I am going to mix in crusaded scoria (lava rock) to add strength and still give good insulative value and light weight. Off to get the correct mix now :). Thanks!!
RE: Aircrete is collapsing
@FoamAir I followed this recipe with my own foam that weighs 85g / ltr made with reverse osmosis water and 7th gen foam. My slurry seems thinner and runnier than yours but maybe that is the pictures not showing up well. Also, there is sand sitting in the bottom of the mix. The cement mixes but there is sand at the bottom in the slurry and after the foam is added as well. Did you have a bit of sand sitting at the bottom too?
I have formed it and can hear my foam reacting one in the form, it is gassing off and collapsing. I will go buy a small foamer and try. I have Drexel on the way. This is all with reverse osmosis water, foam and slurry. Thoughts?
RE: Mini batches
What i like to do is simple math and divide by 10. 94lbs of cement becomes 9.4 (and you can buy 10lb bags at true value hardware in states). 7 gallons water becomes .7 gallons water. 50 Gallons foamed becomes 5gallons foamed. So there is a mini batch. This still requires same density foam.