Oh, but it does make sense.
If you´re building contact coils of the same length and diameter, wire gauge doesnt really matter when it comes to total surface area. The difference is definitly NOT significant. The vaping myth of "thick wire means more surface area" is incredibly short sighted and borderline dumb. You get large surface area by building large coils; not by using 20G.
You dont have to believe me on hot air out of my mouth alone; I´ll math it for you:
Wire 1 has a thickness of 0,5mm; wire 2 has a thickness of 1mm. (Random numbers for easier calculations; also, I´m a scientist and from Europe, so Gauges can go f... themselves). If I want to build a coil of the same size I need double the amount of wraps of wire 1, so I need roughly double the length of the wire (say 20cm of 0,5 and 10cm of 1mm wire) to get the same size for the finished coil.
Total surface area will calculate as follows:
Wire 1: 0,5 x 20 000 = 10 000
Wire 2: 1,0 x 10 000 = 10 000
They are the same. (Yes, factor 2π is missing; but this is the same for both calculations anyway)
Now for volume (which, in the end, equals mass):
Wire 1: π x 0,5² x 20 000 = 5000π
Wire 2: π x 1,0² * 10 000 = 10 000π
The thicker wire build has double the volume/mass.
He doesnt mean coil temperature, but the temperature of the vapor. Thinner wire builds running cooler can be explained by the fact that thinner wire has a higher efficiency then thicker wire. By that I mean that more of the applied energy is used to vaporize liquid instead of heating your atty and the air above your coils. More vapor production with same energy means better cooling, as vaporisation just cools stuff. Lick hand and blow on it for example.
Thick wire has more metal thats further away from your wick (if that makes sense) and this "excess" will be heating the air above your coil more then actually using the energy to heat/vaporize liquid. This is also the main reason why thin is more efficient in the first place.
All in all; this explains why thick wire = warmer vape[/QUOTE]
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You are calculating the width of the coil, not the surface area. Using your numbers where wire 1 = 0.5mm and wire 2 = 1mm and winding around a 4mm ID jig to achieve 8mm wide coil, wire 1 would have a surface area of 408 mm² and wire 2 would be 528 mm². Both coils have the same width, but with wire 2 being a larger wire, your surface area increases.
So it is not a vaping myth, it is how each wire is applied. Now if we were to increase the ID of wire 1 to 5mm, the surface area would be equal. OR, we could increase the width of the coil for wire 1 to roughly 12mm wide to achieve the same surface area. But both these actions have an effect on the coil.
As for mass, that I am not disputing. But mass is not the same as volume. We can achieve the same volume with 0.5mm Kanthal vs 0.5mm Ni80, but the mass for the same length of wire will be different. Saying that, if using the same metal, say Kanthal, 0.5mm wire around a 4mm jig for an 8mm wide coil will result in a lower mass than 1mm wire around the same 4mm jig for the same 8mm width coil.
Your final comment on efficiency and temperature of the vapor makes sense. But up to a certain degree. You apply too much power to a low mass coil and you end up burning. Too little power to a high mass coil and you may not even vaporize the juice. So how does one test low vs high mass coils by using the same applied power. That is what does not make sense.
I am a firm believer in keeping mass at a minimal while trying to achieve the highest possible surface area, but there are always compromises. Saying that, I applaud Boden for this radiator coil concept