Vibraplane: Should it be loaded close to limit?

I too recently picked up this unit (active version with compressor - 2212-01), and would also like to know the answer to this question. The instruction manual states 275 lbs as the maximum load.

Thanks for digging this up Pete, much obliged.

It certainly is an interesting unit. Since my table weighs around 120 lbs, I've also simply placed it on top of the Vibraplane. The active system makes leveling a whole lot easier than the passive version I'd guess - mine maintains level perfectly once you set the three thumbwheels to the correct height (I'm at 3.75 inches for now). The compressor kicks on once every six hours or so, so I either have a very very slow leak, or that's just how it functions...comments on the interval of compressor cycles would be welcome. The compressor is a Jun-Air, and is the most silent air compressor I've ever experienced - you only hear it click on and off; I think they were designed for dental offices.

My initial impressions are of a drop in background noise by several orders of magnitude, not a softening of the sound, but rather a very black background. Low frequencies certainly have better control and articulation, especially way down low. My concern at the moment is the nature of the top plate itself - given that it's non-magnetic stainless steel, the same material as the cones on the bottom of my deck, I notice a bit of stridency introduced into the upper midrange, a quality that was absent with my aluminum top-plate sandbox. I'm guessing I'm getting a bit of 'chatter' due to the two equally hard materials interfacing with slight surface imperfections exacerbating the situation. I'm going to experiment carefully with intermediary materials between the deck and the Vibraplane, either substituting cone material or introducing another shelving layer between the two.

At 180 lbs, the Vibraplane is a two man lift to be sure, so haphazard swapping in and out is not on the agenda. It will be a while before I solidify my thoughts on what, exactly, it brings to the table over alternative isolation methods, such as my beloved sandbox.

Dan,

The surface has no holes; it's an option. I did think of putting my sandbox directly on the VP, but it was too heavy (around 190 lbs (!)) - we each stood on a separate bathroom scale, and aggregated the results, minus our respective weights. A funny sight to be sure.

Dan,

Indeed the Vibraplane uses a type of air spring which I think contributes significantly to its excellent horizontal isolation; they are not mere bladders, or else I'd just do the inner tube trick and be done. The compressor has a regulator and moisture trap, and the Vibraplane has its own regulator valve as well. Alas, I traced the leak back to the unit itself, and not the air line(s) on or from the compressor. While I am uncertain if it's actually an air spring leaking or one of the leveling regulators (for lack of a better term) it still means having to flip it over to find out - soapy water at the ready. There's also a lot of air tubing running all over the place under there, so it could be that as well.

Needless to say, I'm going to have to return to the sandbox for a while until I can pin down the problem. Of course cajoling friends into helping one heft these things around usually takes a free dinner and plenty of beer...ah the lengths we go to for this hobby.

The one on ebay looks ancient! I think $100 is optimistic for a shipping price, as you'd need to use a freight carrier.

Thanks Dertonarm, good to know. Cheers!

-Richard

Peter,

Thanks for your detailed experimentation and findings.