Skeletal vs Plinth style turntables

Viridian
Given that any structure has a resonant signature, the question then becomes not, "which is the most dead" but "at what frequencies are the resonances in the structure and what is the amplitude, magnatude, and Q of those resonances?"

+1 Excellent Viridian

One example of this.

"Granito is a material composed by little pieces of marble of very different origin agglomerated inside a mold with cement. Machined and polished. The resonance of the plinth with its suspension is about 5Hz and it is well absorbed by the air cavities"

Mr. J.C. Verdier (R.I.P) in describing the Verdier Vintage La Platine Granito.

Along with La Vintage Platine, I also "still" own two full plinth TT's, My 100 lb Jean Nantais Lenco, and an SP10MKII that can actually be put in one of two configurations. 1) A Full Plinth - 70 lb Multi 6 Layer Birch/ One layer MDF or 2) a Rigid (in your words ParrotBee) Skeletal Plinth.(both plinths which are DIY sourced and put together). The SP10mkII is sort of a pet project going way back now. fwiw I prefer it in its Rigid Skeletal Plinth form. It is more neutral sounding.

A further point following Viridian and Ct. When I first became interested in DD tables Corian was often mentioned as a recommended plinth material. But then I read more than one negative comment on that. Further reading disclosed that Corian includes some amount of aluminum flake in its composition. Apparently that varies among samples and that quantity can have a sonic impact. Bottom line, simply choosing Corian may not allow prediction for how it will sound.

Unfortunately it seems to me the best answer is to follow Ct's path and experiment with alternatives.

I know this may seem pedantic, but is there a special glue when gluing together layers - in other words - what glue do the likes of Kronos and Clearaudio use when sandwiching aluminium and panzerholz

Made a table a few years back from Cocobolo laminated with Aluminum, glued the 5 layers (3 cocobolo 2 aluminum) together with a 2 component Epoxy glue, still hold up very nicely. The aluminum layers were "timesaved" which is the typical graining you see on for an example your typical Face Plate.
System 3 Epoxy

Good Listening

Peter

Some 20 years ago when I was building my current SP10 MK3 plinth, I spent a lot of time experimenting with glues.
I was using CLD on the acrylic top plate. In this case a 15mm layer of lead was to be adhered to the acrylic.
I initially thought that a lossy type glue, such as ados, would be optimal but listening to the test pieces thru a stethoscope while tapping it gave a "thunk" type sound. This was not what I expected as I was trying to emulate the ideal water fall type plot as we see published in speaker tests.
That is a sharp rise time with very little tail to the sound.
I then started experimenting with epoxy glues and settled on an industrial araldite epoxy. This lead to protracted experimentation with harder and filler ratios. I found that I could further reduce the tail of the tapped sound by optimising the hardness of the glue.
The final result gave a very short sharp "tic" when the workpiece was struck.
The result was a kind of fusing the acrylic to the lead. In this way they behave as a intimate composite structure.
Aiding this was massive clamping pressure while the glue dried. Over one tonne of cast iron billets were stacked on top of the plinth during the curing time.
Epoxy heats up when mixed, so the glue becomes quite runny. The vast majority of it oozed out between the layers. Unwilling to let this excess set, which would have required expensive remachining, I spent almost all night until just before dawn removing the excess as it flowed out.

Fun.