Finally tried a contact coil after reading yesterdays posts here, thanks finally got a good vape, w/28g 11 wraps on 3/32nds, came out to .16 ohms on meter, .15 on VF. (i did the math based on .3778 ohms/ft on 28g Ni & got that it should have been .11 ohms, so not sure what's up w/that but my 2 prior Ni coils also read higher than calculated on 2 diff meters and the VF)
It took close to 8 watts to pulse it enough to pinch it just a bit w/ceramic tweezers, but outer wraps on each side were having a tough time getting heat to them (with or w/o tweezers) even tho i pulsed it enough that middle of coil was glowing orange, & had it been kanthal the entire coil would have been orange. It's vaping good now for the 1st time, but i would try 9-10 wraps max of 28g next time. (usually do 8 wraps w/kanthal, and now can practice spaced coils some other day).
Not gonna take apart an R91 for a 4th time until there's a problem w/this coil, but my guess is that too many wraps makes middle section of contact coil hot while outer edges are cool, but since the board reads average temp & i don't have infrared temp sensing equipment i got no clue how extreme the difference may be. I don't recall ever seeing kanthal behave that way to that extreme. Not sure what the implications of that may be, but will try just 9 wraps next time, maybe 10 max. (unless/until my vf tweaks also)
Also had a hot leg in a tiny piece of wire where i clipped it after going a full 360 around the post screws, but it was fine as soon as i tucked that tiny piece under the screw.
Am dreading what may happen once i vape a few tankfuls w/tc, only had this thing 3 1/2 days.
