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dielectric constant for glycerin
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Doctorandus_P:
I would probably make a capacitor like this from glass plates and 2 pieces of auminimum or copper foil.

You can fold one piece of foil zig-zag from left to right and the other from top to bottom.
For higher pulse capacity use loose sheets of foil and connect them all together.
Use glass plates that are a few cm wider than the foils to crate gaps and maybe put the whole thing in some liquid to isolate the edges further.

"Regular" glass has a relative permitivity of 6 to 8, so you'll need more layers, but you'll have to mess a lot less with liquids.
It might be worth putting dabs of silicone or whatever on only the corners of the glass plates, for extra isolation.

coppercone2:
why can't you dry glycerin over phosphorus oxide or oleum?

I think you can in a vacuum desiccator.


Intensity and capacity of common desiccants

Drying agents can conveniently be grouped into three classes, depending on whether they combine with water reversibly, they react chemically (irreversibly) with water, or they are molecular sieves. The first group vary in their drying intensity with the temperature at which theya re used, depending on the vapour pressure of the hydrate that is formed. This is why, for example, drying agents such as anhydrous sodium sulphate, magnesium sulphate or calcium chloride should be filtered off from the liquids before the latter are heated. The intensities of drying agents belonging to this group fall in the sequence:

P2O5 >> BaO > Mg(ClO4)2, CaO, MgO, KOH (fused), conc H2SO4, CaSO4, Al2O3 > KOH (sticks),
silica gel, Mg(ClO4)2·3 H2O > NaOH (fused), 95% H2SO4, CaBr2, CaCl2 (fused) > NaOH (sticks),
Ba(ClO4)2, ZnCl2 (sticks), ZnBr2 > CaCl2 (technical) > CuSO4 > Na2SO4, K2CO3

Where large amounts of water have to be removed, a preliminary drying of liquids is often possible by shaking with concentrated solutions of calcium chloride or potassium carbonated, or by adding sodium chloride to salt out the organic phase (for example, in the drying of lower alcohols).

Drying agents that combine irreversibly with water include the alkali metals, the metal hydrides, and calcium carbide.
Marco:

--- Quote from: Doctorandus_P on March 21, 2019, 09:18:25 pm ---I would probably make a capacitor like this from glass plates and 2 pieces of auminimum or copper foil.

--- End quote ---

Weight or volume wise you're going to be way over an oil solution. The oil can be dimensioned much less conservatively, one dielectric failure with oil and the oil is a slightly less good insulator ... one dielectric failure with glass and it's gone. Oil is generally the one to beat, the way to beat it is better dielectric constant (ultrapure water or high K ceramics) or better dielectric strength (BOPET, BOPP).
bson:
How about experimenting with epoxy resins?  Coat the boards in a plain protective layer first, then pot the whole assembly with a mix of ferrite dust and resin...  That should give you a sky high relative permittivity! Maybe use a vacuum chamber to eliminate air bubbles or pockets?

Just thinking out loud here.

Edit: maybe confine the high-µr mix to the center so it can't conduct fields around the plates...
Marco:
If there were easier ways than the complex ceramics to make high k dielectrics, the capacitor manufacturers would be using it ... you're not going to beat just using the same dielectric strength of mylar, infact you will likely lose by a lot.
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