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The EarthTainer III Aeration Bench - Torture Test (pics)

Posted by rnewste 8b NorCal ( on
Sun, Jan 23, 11 at 21:37

As "calistoga" had pointed out, the support for the Aeration Bench in the new design raised some questions. To do a stress test, I decided to "water-board" the design to determine if the support assembly will indeed hold up.


The ultimate weight "challenge" was to fill the Aeration Bench (without holes) with water, trying to collapse the Bench support assembly. As a worst-case test, I did NOT attach the two bolts that secure the upper portion of the Aeration Bench to the outer container. I then applied a maximum dead weight load by filling the Aeration Bench to the brim with water. Fully loaded, it held 21 gallons. This equates to a mass of 175 pounds sitting soley on the bench assembly:


To be expected, the sides of both (unsecured) containers flared out. But now after 10 hours the bench assembly is holding fast.

Next, I built a second 'Tainer but this time, securing the two containers with the two upper bolts as per the Guide:


Upon filling with 21 gallons of water, notice there is much less flaring of the sidewalls, as compared with the unbolted set:


I plan to let these two 'Tainers sit as is for the next 7 days to fully evaluate the strength of the bench support assembly with this load. Of course, in real use with Potting Mix loaded, I am calculating a typical load factor of approx. 80 pounds, figuring in the (light) weight of the Bark fines plus Perlite. So, as of tonight I am pleased with the structural rigidity of the EarthTainer III design.


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RE: The EarthTainer III Aeration Bench - Torture Test (pics)

A week later, and I am happy to report that neither the EarthTainer III with the upper anchor bolts, nor the worst case test unit without the upper anchor bolts failed the 175 pound weight test.


In removing the unbolted Aeration Bench to look for any deformities in the support assembly, it looked as new:


Even examining the bolt holes themselves where stress would have occurred, everything looks fine:


So, my conclusion is that securing the Aeration Bench to the outer container with just the two upper bolts as in the current Guide is more than sufficient.


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