I just tried using stainless mesh wound straight onto cotton and found it works pretty well:
(soz for phone camera and shit-tier build)
There are three main things that I think this is good for:
Since it is so thin and spread out it has very little thermal mass so there is almost no heatup/cooldown delay.
The juice wicks into and through the mesh, giving an excellent surface area and no part of the coil surface can really dry out mid-puff unless the cotton does not wick fast enough.
Also the efficiency is pretty high due to the large surface area to coil mass ratio, I suspect the efficiency that can be obtained from fine mesh may be higher than can be achieved with wire but that would require a comparison.
The main downside is that it is fiddly to wind since the mesh is not rigid which also means that you need to watch you don't short the loops (courser mesh would help here and also help with the ohmage) and I think it might get gunked up quicker (I'll see how that goes, it might not be a problem even if it does).
I'm not exactly a flavour connoisseur so I can't comment much on that but it seems the same as good pre-built coils. My throat is rather sensitive to burnt juice and bad coils in general though and the vape comes off this smoothly enough for me to handle the same sort of clouds as with pre-built TFV4 coils (but at a fraction of the wattage, the sextuple coils munch batteries like popplers).
The mesh was folded in half (double layer) and wound straight onto the cotton, mandrels are not much use. I don't know what micron this mesh is, I couldn't even count it with my binocular magnifier but it looks like 10-20 threads per mm, it's finer than it looks in the image, feels silky smooth and bends like receipt paper, I just got it with a cheap rebuilding kit that I wanted the mandrels out of. I think courser mesh may be better for getting a lower ohmage and make it easier to build so I'll buy some next time (this was 1.4ohms and ran nicest for me at 20-25W but I run most things at a fairly low wattage for the coil size). I couldn't find any posts about people using coils like this, is there a name for it yet that I can search? Also I think this can be done without cotton, possibly even with a tank with the fine mesh holding back the juice in the same way as the cotton cylinder in a pre-built coil.
The wicking benefit arises from the fact that the surface tension of liquids is a more dominant force at smaller scales, fine structures and small holes wick better because they literally suck harder, it's capillary action. This is exhibited somewhat by clapton coils and most coil art things since they have all the little gaps for the juice to wick through but they are still pretty course compared to most meshes.
Anyway, I would be keen to hear what an experienced vapist thinks of this stuff.
Side view:
The RTA coil in it's natural habitat:
Bonus photos of the other thing I made from mesh, a silly RDA "coil" that sort of works (the juice wicks upwards through the mesh fast enough to actually work (sort of lol, I was thinking of making another oil vape but changed my mind so I did, uh, that...)):
https://i.imgsafe.org/ac6df4a691.jpg
https://i.imgsafe.org/ac6df98ed5.jpg
I forgot to get a photo of the coil burn, surprisingly there were no contact point hotspots, though it was a pretty uneven glow since it is utter trash. There might be a salvageable concept in there somewhere though especially if you form the coil rather than just smooshing a pile of mesh.
(soz for phone camera and shit-tier build)
There are three main things that I think this is good for:
Since it is so thin and spread out it has very little thermal mass so there is almost no heatup/cooldown delay.
The juice wicks into and through the mesh, giving an excellent surface area and no part of the coil surface can really dry out mid-puff unless the cotton does not wick fast enough.
Also the efficiency is pretty high due to the large surface area to coil mass ratio, I suspect the efficiency that can be obtained from fine mesh may be higher than can be achieved with wire but that would require a comparison.
The main downside is that it is fiddly to wind since the mesh is not rigid which also means that you need to watch you don't short the loops (courser mesh would help here and also help with the ohmage) and I think it might get gunked up quicker (I'll see how that goes, it might not be a problem even if it does).
I'm not exactly a flavour connoisseur so I can't comment much on that but it seems the same as good pre-built coils. My throat is rather sensitive to burnt juice and bad coils in general though and the vape comes off this smoothly enough for me to handle the same sort of clouds as with pre-built TFV4 coils (but at a fraction of the wattage, the sextuple coils munch batteries like popplers).
The mesh was folded in half (double layer) and wound straight onto the cotton, mandrels are not much use. I don't know what micron this mesh is, I couldn't even count it with my binocular magnifier but it looks like 10-20 threads per mm, it's finer than it looks in the image, feels silky smooth and bends like receipt paper, I just got it with a cheap rebuilding kit that I wanted the mandrels out of. I think courser mesh may be better for getting a lower ohmage and make it easier to build so I'll buy some next time (this was 1.4ohms and ran nicest for me at 20-25W but I run most things at a fairly low wattage for the coil size). I couldn't find any posts about people using coils like this, is there a name for it yet that I can search? Also I think this can be done without cotton, possibly even with a tank with the fine mesh holding back the juice in the same way as the cotton cylinder in a pre-built coil.
The wicking benefit arises from the fact that the surface tension of liquids is a more dominant force at smaller scales, fine structures and small holes wick better because they literally suck harder, it's capillary action. This is exhibited somewhat by clapton coils and most coil art things since they have all the little gaps for the juice to wick through but they are still pretty course compared to most meshes.
Anyway, I would be keen to hear what an experienced vapist thinks of this stuff.
Side view:
The RTA coil in it's natural habitat:
Bonus photos of the other thing I made from mesh, a silly RDA "coil" that sort of works (the juice wicks upwards through the mesh fast enough to actually work (sort of lol, I was thinking of making another oil vape but changed my mind so I did, uh, that...)):
https://i.imgsafe.org/ac6df4a691.jpg
https://i.imgsafe.org/ac6df98ed5.jpg
I forgot to get a photo of the coil burn, surprisingly there were no contact point hotspots, though it was a pretty uneven glow since it is utter trash. There might be a salvageable concept in there somewhere though especially if you form the coil rather than just smooshing a pile of mesh.
(and I am so glad it did) and mine did not and I quickly got over the failure.
