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Wax comes in all kinds (paraffin, bee wax, palm oil wax, gel wax, ...) but since it's usually a mixture of different carbonated chains, its physical properties vary a lot from one manufacturer to another.

A good candle is usually one made of a wax with a high melting point, such that it takes longer to burn.

I am trying to make a bad candle, more specifically I am trying to make a candles that produces as much wax vapor as possible. To make it happen, I am looking for a wax that has the lowest possible boiling point.

How can I lower the boiling point of a given wax (paraffin wax for instance since it's the cheapest and easiest to buy) by adding other substances inside ? One can easily find on the internet how to increase the BP (by adding stearin for instance), but not the reverse.

Ideally the additional substance should not be added in too great proportion, since that would lower the wax composition and thus the amount of wax vapor emitted.

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How about mixing your paraffin wax with some paraffin oil which in practice is liquid wax (just shorter parafinic chains) in the appropriate ratio to get whatever melting point you like?

The boiling point and the amount of wax vapours is a different story since as Karl said wax is a mixture so even if it could be boiled (most likely under vacuum, otherwise it will autoignite) it will fractionally distill so it wont have one boiling point really. Also the amount of wax vapour will be small in all cases since the wax will burn to CO2, CO and H2O (however you could have some lower boiling point hydrocarbons flying around if you mixed your wax with them but that wouldnt be wax vapours then).

If you really wanted to lower the boiling point of your liquid you would need to mix it with something that will form a low boiling azeotrope mixture. No idea what that would be for wax.

And lastly, taking James' thought below a step further, if you would like a really really "bad candle" just use one of those old oil lamps. The way they work is exactly the same as a candle but the waxy bit is a liquid so it needs to be in a container. Then you have a wick just like candles do. Only difference is you dont need to melt the wax first in order for it to be sucked in the wick since it is already a liquid.

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Whenever you just mix two substances (dissolve in each other), you lower the melting point and raise the boiling point. That's a fundamental principle. If it was the other way round, the substances would not mix, or at least not mix well.

(Azeotropes of compounds with very different polarity (water/ethanol) are the exeption confirming that rule, but the acchievable raise in Bp. won't be large. And I doubt you find one you can make a candle from.)

That sounds bad, but: Paraffin wax already is a mixture, so the desired effect might be reached by fractionating it, instead of adding sth. else.

You might try to slowly crystallise a molten sample of paraffin wax, and pour off the residual liquid when the sample is about half solid. Now the residual solid should have a higher melting point than the original wax.

(Note: This is purely my educated guessing, no idea if the effect is large enough or if some secondary kinetic effect might completely preclude it.)

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Two points: melting point and boiling point. Hmmm. If you lower the boiling point, you will likely also lower the melting point, so your candle will be really bad - it will drip away.

Well, let's take a low melting "wax", like petrolatum (Vaseline). Mix in a stiffening agent like fumed silica or cellulose fiber (it will burn off when the flame hits it). The wick should be thick to hold the melted petrolatum.

This might resemble a torch, with a huge flame. To moderate it somewhat, you could blend paraffin with the petrolatum.

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