Drexel Foam Density



  • I'm new to making Aircrete and have been testing different configurations for the last 3 weeks.
    During these tests I have had issues related to my Aircrete samples shrinking from ¼ to ½.
    Here are just some of the recipes that I used:
    Sample 1:
    1 lb Portland
    8 oz water
    1 3/4 quarts of Foam (Drexel @26 grams per a gallon of water with density of 1 quart @92grams) 20200411_110731.jpg bolded text

    This resulted in shrinkage and a poor distribution in my mix.

    After about 10 different mixes I purchased the Panel Mix recipe from HDC. This resulted in much less shrinkage but it was still shrinking.

    At this point I re-watched as many YouTube videos and started to notice one big difference.
    I noticed that the Foam that others were using looked much thicker.
    I then decreased the foam density by increasing the air pressure which resulted in a density of 1 quart @46 grams.
    This density with the HDC mix resulted no shrinkage with the exception of surface bubbles popping which is expected.

    Has any one else experienced these issues?
    Please let me know.
    Thank you in advance!



  • I ran a second test tonight and this time I used clear 5 quart container to test how long the foam would last. During this test I got my foam generator set up so the output was 1 quart @94 grams.
    I then filled up the 5 quart container and set it aside.
    After about 10 minutes I noticed that the bottom of the container had about 10 oz of water in it.
    I repeated the test again after about 10 minutes it had about the same amount of water on the bottom.
    The kicker here is that the top of the container never dropped so it looked like it was filled the entire time! The picture below shows the water level after about an hour.
    20200427_201015.jpg

    I'll try this same test using a density of 48 grams tomorrow and post the results.


  • Little Dragon Tamer

    I will be following this post closely. I have purchased the Drexel but not tested it yet. I will post when life let's me get it done. Hoping several others will post experiences as well.



  • Yet another round of testing!
    This time is set the foam density to 1 quart @42 grams.
    20200428_185449.jpg
    As before, I waited for about 10 minutes and checked the water level.
    This time I had still had water on the bottom of container but it was much less around one ounce.

    20200428_190833.jpg

    The big difference here was with the quality of the foam. The foam was much lighter and looked much weaker. It definitely did not last as long as after an hour it started dissipating quickly.

    I'm going to try another test tomorrow by increasing the amount of Drexel from 26 Grams per a gallon to 36 grams per a grams a gallon and see what the results are.



  • Foam Test Number #4:

    For this test I wanted to validate the ratios I was using with the actual instructions on the bottle (Yes I know RTFM!). After reading the instructions and comparing it to the mix I was using I realized that I was adding by far more Drexel than the instructions called for.
    I was using around 26 grams per a gallon because I found that ratio on a site somewhere and decided to use it. The actual instructions call for 1 to 160 mix. I was always plus or minus a gram when trying to measure out the Drexel so not only was I off on the ratio but off on the mix I said I was using.

    Fast forward to tonight, this time I measured out 14 grams of Drexel (I was going for 13) and then multiplied that by 160 which gave me 2,240 which was over 2 ½ quarts. While this may not seem like a big deal it it is when you are mixing up 1 or 5 gallons at a time. In this case I would have been shorting my solution that I was making before by 1 quart of water!
    To be clear, here is the Mix I used:
    14 Grans of Drexel
    2,240 Grams of water
    Foam Density was 1 quart @94 grams.
    Scale.jpg
    Thickness: Foam was still not a thick as shaving cream or like any of the Videos on You Tube.
    Right after the pour I could not see any water at the bottom of the container. FYI, the discoloration at the bottom of the container are stains from prior concrete mixes.
    Pour.jpg

    I waited for 10 minuets and check to see if any water collected.
    Not settlement at the top and just a bit of water at the bottom.
    10min.jpg

    I checked in on it again after about 1 ½ hours and did not have any settlement at the top and just a bit more water at the bottom.

    It looks as if decreasing the amount of drexel is reducing the amount of shrinkage via Water consolidation at the bottom.
    Tomorrow I'm going to try a mix of 140 to 1 and if time allows one at 200 to 1 with the air PSI at 90.



  • Correction,
    Tomorrow I'm going to try a mix of 180 to 1 and if time allows one at 140 to 1 with air set @90 PSI.


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