Since I last posted the Vibrating Bed Mystery Contest Update in October, I’ve tried MANY solutions to toning down the vibration that shakes me awake in my bed each night. Sleep-deprived and desperate, I pursued fixes by trial-and-error while entering into deep research into the nature of vibration, how it travels, what materials amplify it…very esoteric stuff for a lay person. (The image below of a vibration made on a Chladni Plate is a beautiful symbol of this complex problem).
I discovered that part of the extreme difficulty was due to vibration traveling from the floor UP through the bed. It is MUCH easier to tame a vibration at its source, say, from a piece of machinery under which you can put vibration-absorbing material. Since I knew it would take a while to find the source of the vibration, if ever, I wanted to get the bed calmed down and get some sleep.
An engineer who had worked at the Mayo clinic took an interest in my dilemma, which led to a BIG adventure in pouring concrete, LEAPING into unknown territory and being willing to fail.
Via detailed emails, he suggested that the bed needed weight to overcome the vibration coming up from the floor, at least double that of its normal “loaded state” of 300 pounds (platform + mattress + me): in other words 600 pounds total. He suggested I make four concrete bed legs, each around 75 or 80 pounds to make up the additional 300 pounds needed. (I could also use stacked cinder blocks or concrete pavers — “To make them act as a single mass, you’ll have to stick them together with sanded thin-or medium-set grout or construction adhesive” — or custom-make the blocks. ). Once I had those, he suggested I place two different hardnesses (duro) of Sorbothane disks, a space-age visco-elastic material I had already tried (below), one underneath and one on top of each block in the hopes of further disrupting the vibration.
A very patient product advisor at Sorbothane thought the idea had great merit. However, when he learned that the hertz of the vibration was an extremely rare, low 6 hertz — an essential piece of intel that my advisor didn’t have — he warned me that my labor-intensive fix might not work. Because Sorbothane is formulated to dampen vibration from 10 hertz and above, it was possible that it would have the effect of AMPLIFYING the 6 hertz vibration.
Well, I’d take that chance.
Fueled by the engineer’s advice to “just think of concrete as a giant batch of pancake batter”, I set out to learn to mix and pour concrete on our terrace. How hard could it be? I found a concrete calculator that would help me figure out workable dimensions that would yield 80+ pounds, then bought styrofoam shipping coolers to use as forms for the concrete. I got a local guy to deliver concrete. It’s HEAVY! Then I bought a bucket and a mixing tool and laid it all out on a garbage bag. I donned an old pair of swimming goggles and a cloth respirator mask, along with rubber gloves and set to work.
Since concrete is very heavy and dense, the engineer advised mixing smallish batches and pouring them into the form. After my first batch, the bottom of the bucket cracked. Undeterred, I turned the bucket over and patched it with trusty Gorilla tape, then kept going.
That’s when I discovered just HOW HEAVY concrete is and that it is hard work to hand mix 90 pounds of concrete in a bucket. But I forged ahead and mixed batch-after-batch until the styrofoam form was filled (and the nice clean workspace was a mess!) I tapped the side of the box as to make the concrete settle uniformly and make air bubbles rise to the surface.
I cleaned up the mess and waited to see what my first concrete pour would yield. After a few days, I turned the block out of the form and voila: my first magnificent block (here and at top).
As much as I was thrilled to have made a block, I knew that making three more would take a lot out of me, even if I switched hand-mixing to the rake and tub method we saw in a video online. Just getting four 60-pound bags of concrete up to our city apartment would be an undertaking. Thankfully, Holton Rower, whose art studio is a veritable arsenal of heavy-duty tools and materials, came by with his powerful drill that could drive a concrete paddle. Together, using his down-and-dirty-get-it-done method, we knocked out the three blocks. Holton advised me not to bother getting the air bubbles out (“they’ll look interesting!”).
Holton’s blocks did indeed look more interesting than mine…
I used a hand truck to move the blocks into the bedroom. Bruce McKenna (who originally helped devise the yoga block-and-closed-cell rubber vibration damping that worked initially) taught me how to use sheets of wax paper under the blocks to slide them easily into place at the each corner of the bed platform. We set the Sorbothane on and under the blocks.
That night, I awoke to a juttering bed. The Sorbothane had indeed amplified the vibration which defiantly came up right through the concrete.
Disheartened but not defeated, I continued to practice Improvised Life’s essential principles: Solutions lie within the moment. We just have to find them. AND
Failure teaches many lessons. I learned A LOT about vibration and now know how to pour concrete, move heavy weights, how vibration travels…
I’ve also had to maintain a practice of keeping faith that I would find an answer, perhaps the key to it all.
I have found some answers, but not at all the one I expected. Stay-tuned.