Ok guys, did the 28g build. It didn't come out perfect but most of the wraps were touching eachother. Mac, I was going to go for 11 wraps, but I took your advice and tensioned it down to 10 wraps (from about 16). I figured 10 wraps would be better for my eVic anyways, since any more wraps would take a while to heat up, with thicker 28g wire.
Good thinin' babalui. Good test. Good approach. Working out the kinks on the compromise of 29 AWG on KPT's at the moment myself. Does help in transitioning some of those coils to small drippers or tighter builds elsewhere.
I just have concluded that
28 AWG is just overkill on the Protank. I don't believe the results many are reporting as simply unsustainable or producing the kind of results most of us can enjoy. I'm certain it happens, some get it, but it doesn't play nice, not for long. And, even as I've watched all the hoopla from Rip T on down, the confines of a KPT cup are so limiting and the
wonkiness of its 510 connect so
unpredictable that it's futile to expect a consistent result. It will blow off with the slightest change, including normal use. An exercise. If you want to fiddle or press the envelope on the oft chance that
it may, fine; but, it gets
undependable and so
it's not for the folks as it
...just doesn't work. I'll explain why using your example...
.. Well I tested it on my eVic and it came in @
1.1ohms. A little lower than I hoped, but it will fire at about 8 watts. I dry/test-fired it and squeezed it tight with tweezers - this part made the coil a little wonky, like I usually do, but still okay...I'm pretty sure 1.1ohms is the lowest coil build that my evic will even fire, I don't believe it will fire a 1.0ohm coil so I got lucky!! Next time I'll try 11 wraps, but 12 might take too long to heat up on this battery.
.................... Btw, I took pics of the entire build and I'll probably post them tomorrow. About the try this bad boy out now, I'll let you know how it goes!
I want to correct a misconception here. There is no big advantage in torching coils. As I mentioned early on it can degrade the wire. Nothing more frustrating than putting together a great wrap, trying to improve an end turn after the torch squeezy thingy and snapping a wire doin it'.
It is easy to break a wire once its torched. So squeezing and torching and compression and pulling to rewind are tools, a means to an end. But frankly mostly theater. Not necessary. Useful sometimes to lend rigidity to a wrap once perfected,
not if you're only then going to de-wind or reform it in any way. That defeats the purpose. I demonstrated or discussed them as
a means to introduce certain concepts on this thread. I believe the REO community on this forum, most familiar early adopters of the microcoil, has been aware of this from their early use of contact coils, that it gets to a better coil integrity when you anneal and pulse on the mod. So God forbid anyone should take away that my suggestions should be construed as gospel, rather presented as useful exercise. I'll state if they're my conclusions, as I have above. So don't take my word for it, try it, do it. That's what I encourage. Testimony is great, but its just that, anecdote. Make up your own mind always.
Prove all things. And if we really want to be of memorable importance to those around us, on this thread or anywhere, share and teach the means for people to accomplish that.
On to your build M
and I've concluded, you have a short. As I've suspected for a time and can't tell you exactly why but also suspect it may be resulting from part of your build technique, as it was for me. At some juncture you may be deforming a wire somewhere. Here's the why
the lowest theoretical resistance for the wind you describe is ~1.299Ω (a total approx wire Len of 75.17mm, inc 7mm/8.25 neg/pos minimal observed leg Len for the KPT). If you're seeing anything less than that, and unless I am mistaken about the math, you have a short. And as you know eVic's are phenomenal at resistance variation errors on installation. I'm guessing this time it wasn't.
So this is just not a story, like so many on ECF, and folks can get some context here, the following link provides a fairly good calculator for estimating the wire length parameters for your build. There are many available on the internet, here's one for you to expedite your cross-check now. Use TEMCO's wire tables of Ω/ft specs, unless you're using other. And you now have a report on min found values for leg length from me. I can only affirm I've measured many dozens of them. I don't save them for posterity. The few survivors are working in drippers. Too easy to spool a new one. Here you go with a screenshot of your build spec following the link
Helical Coil Calculator
(Sorry the pic is arbitrarily scaled: LenW=2.359, DiaD Ø=0.0751, N=10, S=0.)
For me M the goal here and on Metalhed's thread has been simple. Use precise coil wind localization, stabilization and termination as a first step to get folks towards targeting temperature, through some essential typical res. targets and then through the use of the most efficient and simple wind/build method possible to make a proper electrical coil. I think we're just about there with this last step providing an approach to proving assumptions.
Please do M as you sort out this termination issue, try to do the wind off the coil as the possible simple answer. It is far and away more difficult to try to keep them wires straight and honest with an external object like a needle nose, even though far better than hand/finger pulling. And believe it or not there is more tension, more consistently applied off a spool. It's the separation pressure we can apply with hands and forearms, even for a child, that is greater and constant. That's what guides the wire straight. It does not take a lot of pressure at all to get to a threshold where you see adhesion occur from wire to wire. Once that happens you're golden. A few tries and you will
feel exactly how much is required to get there and the immediate form integrity that results. I don't know exactly how many Neutons of force but I'd guess a child has a greater concerted hand/forearm pull strength at least equal to if not greater than the average man's grip strength (especially
crunchy squeezy thumb and index which is at most 50% of that).
When you do this, I'd love to see the result and the resistance outcome your first try.
I really hope this is helpful to you and those trying to get past that first real trial of building of a proper electrical coil, not just a best stab or guess. It makes a hell of a difference when you actually get it. And I encourage all to try.
Good luck.
