Aircrete is collapsing
I have never had the problem of foam collapse my self. I have seen poor foam that turned to light and airy quickly though when the water pump is priming. Personally I don’t trust the foam weight method so much. I tend to test my air pressure with displacement ratio. I have found that if you can expand 1 gallon of water/ foaming agent to 10 gallons of foam you will typically be at the desired weight.. I could be wrong, but I feel there is a point where a bad mix can weight the same as a perfect one.. With practice you will notice the amount of water used will vary largely by batch with very small air pressure changes. I just happened to notice the strongest batches all have that 10:1 ratio when complete
mundane9 last edited by
we witnessed this during the feb 1 day workshop here in Kalapana. That can happen when the mix is not right - usually with the foam density when mixed, not mixed evenly enough, or if it is not poured quickly enough when setting. What kind of soap are you using? There is a specific concentration of a chemical needed that varies greatly depending on the brand of soap used.
ach2oman last edited by
@mundane9 I am using Drexall 160. The directions call for a 160:1 mix however I did go to a 120:1 mix @ 3.0 oz per qt. but noticed a rapid separation of soap and water in the 1 qt weigh container. I think I may have a water quality problem to be honest.
pappythesailor last edited by
I'm happy to report my second aircrete pour went pretty good and I am quite happy with results.
Here is how it happened:
I built a new 18" x 72" form using nominal 1x4x8' on top of a scrap piece of plywood. I laid a piece of plastic on the plywood. Then I screwed my 4 pieces of the edge form together and set the form on the plastic, squared it up, and screwed it to the plywood base. Then caulked the bottom of edge form to the plastic.
Next day after the caulk had time to dry I set up my tools and materials. Doing my calculations I figured I needed 20 gallons of aircrete so I just cut Domegaia's recipe in half.
So I put 3 gallons of rain water into a 20 gallon galvanized trash can I bought for $20. Then I mixed up my foaming agent using the Drexel F/M 160. Using a bathroom scale I weighed out my portland to approximately 48 lbs. (1 gal. H2O = 8 lbs. X 3 = 24 lbs. With 1:2 ratio cement weighed 2 x 24 = 48 lbs.)
When I bought my 1x4s I also purchased some bamboo tomato stakes. There were (6) 6 ft each in a pack and I bought 2 for $3.17 ea. I wanted to use them for reinforcement instead of steel rebar. So I cut them to length where they would fit into the form both transverse and longitudinal.
Having everything set up poured the 3 gallons of rain water into the trash can and added the 48 lbs of portland cement while mixing them together. The trash can leaked some but not enough to make a difference. Next I started my compressor and made the aircrete, mixing and adding foam and mixing and adding foam. It is a little tough when you do not have a helper. But I managed.
Having everything mixed I filled my form up. I ran a little short so the panel ended up only 2 1/2 inches thick. I put my bamboo reinforcement in and troweled the surface. And cleaned up.
Next morning it was set and pretty hard. I could not poke my finger into it like the first test block. I poured water on it several times that day and also the next three.
Fourth day I unscrewed my form boards and tilted the panel up and lifted it and took it out to my garden where it is going to be the walls of my raised beds.
I think it was a great success and I want to thank everyone here for the knowledge and expertise shared to help make this a better world to live in.
PS. I have a cousin who lives about an hour away and earlier this year she offered to give me some bamboo plants out of her yard. So I think I am going to take her up on the offer! :- D
@kimo How do you measure that, how do you know your gallon of water is getting you 10 in foam? Are you using the little dragon and mixing inline, as the foam is produced, or do you produce the foam into a 10 gallon total and pour it into the cement mixture, and blend?
My wife and I are getting amazing foam with the Drexel but it is frustrating as we blend with the cement mixture. There is a point where we are trying to pump the foam in to get the recommended quantity for a bag of cement, but it won't quite get there. It seems to start to collapse while mixing, especially when trying to finish up the mixing by blending some surface remnant foam in, while not infusing fresh foam. Just plummets.
You're right, the tiniest adjustments in air pressure drastically change the weight. I feel like the "shaving cream" like foam I am most proud of weighs only 2oz/qt or so , not the recommended 3oz/qt. So we keep adjusting until the weight is right, but that foam is less thick, more watery.
The foam itself, you can see it separates to water some in a clear bucket and does some collapsing in a relatively short time. Maybe this foam quality is why my experience is so bad when blending into cement. We just can't get a batch that resembles the lightweight but dense concrete we want...all are far too airous and brittle. You can poke your finger right into it after several cure days.
Yeah that’s not right at all... any time after the 2nd day it should be pretty difficult to stick you finger in a block... the way I check my foam expansion ratio is by just checking the amount of water I have left after a batch, but that’s more because I have it dialed in already. If I end up with 1 1/2-2” of water in my bucket I assume I’m still in the ball park for the next batch, if not I make a small adjustment for the next one ;)
Starting from Zero.. fill your foam generator bucket 1/2 way, make a mark.. then add 1 gallon of water and make a new mark.. prep 2 empty 5 gallon buckets for foam filling.. after filling the 2 five gallon buckets with foam see where your foaming agent bucket is in relation to the starting mark.. my guess is that your air pressure is too low and you will be using over one gallon of solution to fill these buckets..
There is certainly a point where the water content is too high and it gives an indication that your mix is correct by weight.. This is why I moved to the expansion method. There is only one pressure that makes a 10:1 expansion :)
Oh! And as far as what I do with the test foam.. toss it out, wash the car or something.. foam that’s not injected directly into the slurry will not ever be as good.
@kimo Thanks, brother. Super helpful. I was just about to try my test with Cement All last night and the little dragon pump jammed... it's toast. Magnet around the copper coil is cracked and broken. Nice.
I'm pretty sure the cement all is going to work well. They have a set time increasing additive as well as a thinning flow additive and they work well with the product. Add foam and a lightweight, strong and fast curing product should be the result. Expensive, sure...but when you're making furniture, who cares. I'm normally buying 6 dollar a board foot Black Walnut for my designs.
I ordered a new pump this morning, but it looks like they have the little dragon one made just for them, and I can't see how to buy another from them. The one I ordered should be the same only with a max psi of 70, not 90. Should be alright as 70 is where we seem to be in our Drexel foam production.
Any input on this? Thank you again, Kimo, for your expertise.
@MADE I think the rapid set is a great idea! Really looking forward to seeing how that works for you!
I would be a little sceptical of a 70psi pump though... It’s going to change your air pressure also.. Think about the pressure adjustment as a differential between air and water pressure. If you lower the water pressure 20psi, you must also lower your air pressure to match. Not much foaming action happening at 40psi. I curious where they recommend you buy this pump in the diy instructions? I looked at the aquatec site for quite a while and could not locate the part number of the original pump.. the kicker being the “h” pressure code.. none of the 5800 series go beyond “f” (70 psi). You might try Inquiring with aquatec directly?
Right, agreed. And I am a bit worried about it. It appears from another thread that he says they have Aquatec custom make that spec'ed pump just for them, which explains why we can't find it. I can't afford to purchase an entire new Little Dragon system from them, parts apparently can't be purchased, they don't seem to want to talk to me about my supposed "warranty" (I've tried writing @hajjargibran )...what is a guy to do? The pump lasted less than a week and was super suspect from jump, regularly stalling foam production for no apparent reason. Usually, running clear water through would get her going again, but eventually she just jammed and was done. I think that magnet was always cracked and finally gave up. $500 paperweight and no more Aircrete. I was desperate, so I thought I would try the closet thing I could get. It looks like the new pump I ordered is actually max 60psi! I'm going to cancel. What would you do in my spot?
@MADE I would contact aquatec directly..
I would hope they would warranty the pump. Domegaia would only be an intermediary in that process if they were involved. At the very least they may point you in the direction of a reseller that stocks the correct pump ;)
@kimo Probably where this is heading, but they would be the distributor that actually purchased the pump and has a "receipt" for it, especially if it is a special unit made particularly for them. I don't think there is any way that Aquatec is going to work with me, having zero data, no purchase history to provide. I really need Domegaia to respond to me and help wherever they can. Worse case, sell me another pump if it can't be accessed anywhere else. I can't imagine that I am the first customer ever with a bad pump.
Okay, so for any who ever have a pump problem... Tracy at Aquatec is awesome. She contacted Victoria at Precision Installation Products, the Aquatec distributor that Domegaia purchased these propriatory pumps from. I'm shipping the pump back to the distributor and they will arrange a repair or replacement from Aquatec. There is a 1 year warranty and the manufacturing date is actually on the pump, along with the necessary model and serial numbers. These pumps can only be bought through Domegaia. Not even the distributor can sell one to you, although Victoria is going to contact Domegaia and relay a request to purchase a backup pump, to help us keep production going through a tough time like this in the future. Thanks for your input in all this, Kimo. I'll let you know if Cement All is a feasible product for aircrete. It's an awesome material aside from this use, hopefully it's good for this application as well, if a recipe can be figured.
@MADE Nice! Great info there! I’m sure you will be taken care of :) I wonder more now than ever what the diy plans called for pump wise? Knowing that the pump can not be bought thru anyone but domegaia I’m curious if they list a substitute pump in the material list?
MADE last edited by
I have not seen where they recommend anything but there own. It would sure be nice if they would make their propriatory pump available for purchase affordably as a single item. As a comparison, I have ebikes that have propriatory batteries to operate. I don't have to buy the entire bike again if the battery needs replacement, for whatever reason. I can just buy a battery from Blix. Maybe this experience will encourage them to do that. Kimo, have you heard of or looked into non-protein based foaming agents, synthetic ones? Such as Aerix Industries' Aerlite or Allied Foam Tech? No collapsing there! I'm communicating with them, hoping I can purchase a small amount for our use, although they normally deal with huge quantities for major industrial projects. https://aerixindustries.com/products/
@MADE After seeing what the pump really does, I think you could use any pump that can deliver at the required psi. For example, for tig welding equipment radiators, many times I have used a carbonator pump bought off ebay for 40 dollars. Sometimes these pumps goes out for even 10 dollars. They are used in carbonated beverage machines and you can adjust the psi from 0 to 200 psi. Thefunction of the pump is only to bring the water/soap solution to the inlet of the injector, where the air pressure from the compressor makes the foam, using the steel wool as a filter to make the foam. Nothing really to call home about. There are many pumps that can do this job in case you can not find that exact same pump. The problem with exclusive producst is precisely what you just went thru, so many times, it is better to look at the function and find alternatives. Check on youtube, many people have built their own systems. You could even make a gravity fed system if you put that 5 gallon bucket and a considerable high and just let the mixture into the inlet of the injector.
ach2oman last edited by
@Joe I design my own foam generator and it doesn't even need a pump, just use the the pressure from the air compressor works great.
@ach2oman Any chance on sharing your "pump-less" foam generator? My replacement pump from Dome Gaia arrives today. If it does not work I will need some alternative.