So I did some testing.

First test was to ascertain whether you could heat a water emulsion waxed chain safely on the field after the wax was still a bit runny. I used a Primus power lighter III, so a fairly hot concentrated blue flame. The results were unsurprising. You can dry and melt the wax without too much effort. With the primus lighter it took very little time per link to melt the wax.

Second test was to see the safety aspect, ie. is there a fire hazard while exposing the chain to an open blue flame. I could not get the chain to catch fire but I did develop quite a bit of smoke. One would have to be absolutely negligent while heating their chain in order to cause a chain fire. With the amount of smoke I got out of the chain, lighting a chain on fire does not happen accidentally if one is paying attention.

Third test I did because I was feeling adventurous. A while back I made a small batch of white lightning clean ride copy by combining CRC brake cleaner pro, IPA and rex hot wax. Trying it out reminded me why I stopped using solvent wax back in the day. For some reason a large portion of the solvent gets trapped inside the wax and so the wax remains soft for a long time.

Anyways, I guess most of you reading are getting where this is going...

It turns out, that the fastest, most consistent and seemingly efficient way to introduce wax inside a chain aside from actual hot waxing is to apply ample amounts of solvent wax on the chain and then introduce a flame. The following blaze is quite dramatic and uncontrollable, but it peters out in a few seconds and after the chain cools, it becomes stiff like a hot waxed chain.

Hopefully it's obvious this is not something anyone should do in the field ever. You'd burn your bike or something else. Also some of the burning solvent/wax mixture dropped out the chain and on the non burning surface above which I was doing the tests. Had the surface been dry grass... You get the idea.

The tinkerer in me is immediately thinking of solutions, like carrying a disposable aluminum oven tray (the kind you can use as a single use grill) on which do the burns. But honestly there's still too many issues even though it could be done safely. The first and foremost being that solvent wax is like solvent based dry lube: You go through it crazy fast. Water emulsion wax is more lasting as you use it far less per waxing. The second issue is that I don't know whether the very yellow sooty flame introduces contaminants inside the chain. That could be counter-productive.