Candle Wax Capacitor

Thread Starter

BlackMelon

Joined Mar 19, 2015
168
Hi there!

In Buddhist Temples, there are a lot of trashed candles. I just realized that the relative permittivity (dielectric constant) of the paraffin wax is quite good (2.2). Also, its resistivity is very high (even higher than PET). So, I'm thinking of making wax capacitors out of the candles.

My plan is to, of course, melt the candles first. Then, coat each of two aluminum foils by the candle wax. Wrap them together, like in the attached picture (upper one). Green & Yellow = Foils. Cyan = Candle Wax

The problem is the crafting process. This is just prototyping. Would it be more convenient if I:
1. Roll the two foils first
2. Put them on a grille
3. Put the whole thing in a pot
4. Pour the molten candle wax

Or should apply the wax on each foil separately, wait for them to dry, then roll them together?

I am glad to hear more convenient way to prototype this thing

Best Regards,

PS. I expect that using aluminium foils as anode and cathode will lower the series resistance, compared to using papers.
PS.2 Is there any substance I can add to the wax to make the dielectric constant go up?
 

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BobTPH

Joined Jun 5, 2013
8,685
I think the thickness would be too much to get any significant capacitance. Compare to a layer of plastic food wrap for example.
 

BobTPH

Joined Jun 5, 2013
8,685
It will be just coating. My drawing exaggerates the wax's thickness. lol
I didn’t go by your drawing, I just can’t imagine getting a coating of wax less than about 0.5 mm due to its viscosity. Perhaps at very high temperature in a vacuum?

How do you intend to do it?
 

k1ng 1337

Joined Sep 11, 2020
915
Bob makes a good point. I've made capacitors and the spacing between places must be very small and you'll only be in the picoFarad range unless you have many layers or a giant plate.

Have you done the math for your design using air as the dielectric? What is the capacitance? Then try using different dielectric constants such as common candle wax.
 

WBahn

Joined Mar 31, 2012
29,885
What are you trying to do with these capacitors? Is this just for fun, or are you thinking to somehow make commercially viable capacitors from all of the residual wax?

Wax is not very flexible. Even if you get a thin enough coating to not end up with a very low capacitance because of plate spacing, you will break it all up if you try to roll it.

Your bulk-wax approach is not going to be anywhere near the results you could get just using wax paper.

But even that isn't going to be great compared to alternatives.

You say that the dielectric constant is "quite good" at 2.2. Well... regular paper usually beats that by just a bit and oiled paper is about double that. Water is about 80.

Plastic wrap has a dielectric constant of about 3, and is very thin. Another option is mylar.


As for using the old candles to make something useful, I'm going to guess that the most useful thing they could be used for would be to make, well, candles.
 

k1ng 1337

Joined Sep 11, 2020
915
What are you trying to do with these capacitors? Is this just for fun, or are you thinking to somehow make commercially viable capacitors from all of the residual wax?

Wax is not very flexible. Even if you get a thin enough coating to not end up with a very low capacitance because of plate spacing, you will break it all up if you try to roll it.

Your bulk-wax approach is not going to be anywhere near the results you could get just using wax paper.

But even that isn't going to be great compared to alternatives.

You say that the dielectric constant is "quite good" at 2.2. Well... regular paper usually beats that by just a bit and oiled paper is about double that. Water is about 80.

Plastic wrap has a dielectric constant of about 3, and is very thin. Another option is mylar.


As for using the old candles to make something useful, I'm going to guess that the most useful thing they could be used for would be to make, well, candles.
Why would wax paper be better than heated wax? I'm not sure TS understands how little energy can be stored with primitive construction methods but I can see the idea working and being cheap to build.

The methods you mentioned involve wrapping or handling the plates in some way whereas pouring or heating the entire capacitor in a heat bath would flow wax into all the tight spaces. A mirror on a hot day could work for a large capacitor. The melting temperature is low for the wax class of molecules compared to the metal electrodes which offers an advantage to the home shop.

I'm sure this method has been tested in the lab for viability but I always have my eye open for the next big energy recovery device. I think temporary energy storage from throw-away material is the way of the future.
 
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