TC beyond Ni200: Nickel Purity, Dicodes; Ti, SS, Resistherm NiFe30; Coefficient of Resistance
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@balazsk
Another benefit of your controlled dry burn method...
I decided to do a marathon cleaning of all my titanium coils.
I use very closely spaced coils and I thought I had the spacing uniform but one coil showed a slightly brighter area on the bottom of the coil. Apparently the bottom of the coil had slightly closer spacing on two wraps. A quick insertion of a razor blade and slight twist and the coil showed a uniform glow.
Can you tell that I very much like your method?
I hope so because I do.
Duane
Did you happen to notice how many watts the mod was tp at when set to 600c? Were the coils glowing red at all? Those of us without tcr adj mods could benefit from knowing those two things.
I use 4-5W for the dry burn if I do it without temp control. It's slow and maybe needs some patience, but it is good because you have enough time to stop it before the coil gets too hot.
Thanks. When do you stop firing, as soon as you see red or smoke appear somewhere?
It really depends on the type of the wire. In case of titanium I don't like to heat it to red without temp control but I think it's not a problem with SS or NiFe.
If the TCR can't be set on your mod and you would like to dry burn a Ti coil I think you could try it in Ni mode with max temp. Maybe this temperature will be enough to clean the coil, it will be about 500-550°C.
Hey all, I have a horrible lurgy so might not be around much
Just wanted to say:
First: @balazsk - awesome, and I can't believe I didn't think of that!
Second: My 304 Stainless has arrived from wires.co.uk; good price, good service, but the wire is not on spools, just held together with wire twists in a baggy. Not ideal, I guess I need some spools
Third: My Crazy Wire NiFe has arrived. I paid for Recorded and it looks like they did not send it Recorded. Crazy Wire continuing their lust for great service. Though it did arrive the next day.
More importantly. The wire is very interesting. Soft annealed. Zero spring, literally none. Perfectly clean.
And the resistance, this I can't get my head around. 0.40mm wire, 100mm, 0.623Ω. 6.23Ω/m for 26G?? That's higher than Resistherm at 29G!
I quickly made a 3.0mm 8 wrap coil and it came out to 0.52Ω ish - at SS level, and 25% higher than Titanium
This is either amazing, or terrible - the latter if it's not NiFe at all or doesn't behave like we want NiFe to behave. Maybe it's actually SS, it's got the resistance for it
I will try and do some tests ASAP if the lurgies don't murder me. Most important of course, TCR.
Just wanted to say:
First: @balazsk - awesome, and I can't believe I didn't think of that!
Second: My 304 Stainless has arrived from wires.co.uk; good price, good service, but the wire is not on spools, just held together with wire twists in a baggy. Not ideal, I guess I need some spools
Third: My Crazy Wire NiFe has arrived. I paid for Recorded and it looks like they did not send it Recorded. Crazy Wire continuing their lust for great service. Though it did arrive the next day.
More importantly. The wire is very interesting. Soft annealed. Zero spring, literally none. Perfectly clean.
And the resistance, this I can't get my head around. 0.40mm wire, 100mm, 0.623Ω. 6.23Ω/m for 26G?? That's higher than Resistherm at 29G!
I quickly made a 3.0mm 8 wrap coil and it came out to 0.52Ω ish - at SS level, and 25% higher than Titanium
This is either amazing, or terrible - the latter if it's not NiFe at all or doesn't behave like we want NiFe to behave. Maybe it's actually SS, it's got the resistance for it
I will try and do some tests ASAP if the lurgies don't murder me. Most important of course, TCR.
It literally could be SS. I haven't temp tested it yet, but in a quick test:
0.63Ω coil heated to bright orange glowing, increases in resistance no more than 1.05Ω according to Apollo Reliant display
Even if we're generous and assume the temp is no more than 700°C, that's still a TCR of a paltry 0.00098
More testing to be done, but first conclusion: the wire is not NiFe as we know it, and is quite possibly junk. If we're going to use a wire <= 0.001 TCR, it might as well be SS; this does have a bit higher resistance than SS and so would be a bit more accurate, maybe, but then again we don't even know what's in it.
0.63Ω coil heated to bright orange glowing, increases in resistance no more than 1.05Ω according to Apollo Reliant display
Even if we're generous and assume the temp is no more than 700°C, that's still a TCR of a paltry 0.00098
More testing to be done, but first conclusion: the wire is not NiFe as we know it, and is quite possibly junk. If we're going to use a wire <= 0.001 TCR, it might as well be SS; this does have a bit higher resistance than SS and so would be a bit more accurate, maybe, but then again we don't even know what's in it.
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I spaced the coil and got it up to 1.09Ω = 0.001 TCR, assuming it's not exceeding 700°C which is a big assumption.
Then I put it up to 50W and held it for a few seconds and the coil self destructed (still not going above 1.09Ω)
Yeah I think this stuff is junk. I'm going to ask them for a data sheet /details of manufacturer but I shall not hold my breath.
Then I put it up to 50W and held it for a few seconds and the coil self destructed (still not going above 1.09Ω)
Yeah I think this stuff is junk. I'm going to ask them for a data sheet /details of manufacturer but I shall not hold my breath.
Oh and I've tested two of the spools now, and resistance on 0.32 was higher than the 0.40, by an amount commensurate with it being a thinner wire of the same material.
So that rules out just one spool being mislabelled SS or something (though it's really too high resistance for SS anyway)
If they give us a data sheet and we can see what's in it, it might then be a usable wire as it might be more accurate than SS given the higher resistance.
But at the moment there's far too many doubts. It operates like neither of the NiFe70/30s I've got, not by a long way.
Crazy Wire NiFe: Do not buy this wire
unless and until we learn a lot more about it. Even then, the TCR makes it pretty pointless compared to other NiFes and even real SS which at least has the benefit of higher operating temp and low-to-zero nickel.
So that rules out just one spool being mislabelled SS or something (though it's really too high resistance for SS anyway)
If they give us a data sheet and we can see what's in it, it might then be a usable wire as it might be more accurate than SS given the higher resistance.
But at the moment there's far too many doubts. It operates like neither of the NiFe70/30s I've got, not by a long way.
Crazy Wire NiFe: Do not buy this wire
unless and until we learn a lot more about it. Even then, the TCR makes it pretty pointless compared to other NiFes and even real SS which at least has the benefit of higher operating temp and low-to-zero nickel.
Same result with the 0.32/28G wire. Spaced coil 0.67Ω maximum resistance reading 1.15Ω = 0.001 TCR if it doesn't exceed 700°C, which is unlikely bearing in mind I'm holding my finger on fire for up to 20 seconds @ 20W / 4.6V and it's glowing very bright orange.
As a point of comparison, I just made a coil of the 0.40 SS304 I got today as well. A 0.56Ω coil increases to 0.90Ω, which, assuming 725°C, is 0.00089 TCR - right ballpark for the figure that @vapealone has for SS304 @ 727°C (0.000817 TCR)
EDIT: Though actually if I assume the SS coil is going to 825°C, the TCR comes to 0.00075, even closer to vapealone's estimated 0.00077 at 825. So I suppose 825 is more likely than 725.
So the TCR of this NiFe is, best case, 0.001 at ~ 700°C, but it could be 0.0009 or less at 800°C.
I suppose this doesn't rule out the slight chance that it's higher from 0-250°C, it might be sloping down like SS does. But it's not good, I think we can be certain of that. And the resistance is not so much higher as to put this in any good place on our overall sensitivity chart.
I will properly temp test it just to be sure.
As a point of comparison, I just made a coil of the 0.40 SS304 I got today as well. A 0.56Ω coil increases to 0.90Ω, which, assuming 725°C, is 0.00089 TCR - right ballpark for the figure that @vapealone has for SS304 @ 727°C (0.000817 TCR)
EDIT: Though actually if I assume the SS coil is going to 825°C, the TCR comes to 0.00075, even closer to vapealone's estimated 0.00077 at 825. So I suppose 825 is more likely than 725.
So the TCR of this NiFe is, best case, 0.001 at ~ 700°C, but it could be 0.0009 or less at 800°C.
I suppose this doesn't rule out the slight chance that it's higher from 0-250°C, it might be sloping down like SS does. But it's not good, I think we can be certain of that. And the resistance is not so much higher as to put this in any good place on our overall sensitivity chart.
I will properly temp test it just to be sure.
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Sorry for the post spam. Last point: I still can't rule out this 'NiFe' wire as being some kind of SS. The resistance is a bit higher than the SS' I know of, but only about 10% higher. It feels the same. It coils the same. It has a very similar TCR. It looks the same after being heated and cooled (grey)
And when I heated this SS304 coil at 40W, it disintegrated in exactly the same way as the 'NiFe' did, and under roughly speaking the same amount of heat exertion (can only be judged very approximately, of course)
None of that might mean anything, maybe most wires look the same when they go above their max temps with a few exceptions like Titanium.
But if I'd picked this wire up off my desk without seeing a label, I would have said it was SS.
Is it possible that a NiFe70/30 wire could be so very different to Resistherm NiFe30, Kanthal NiFethal 70 and Stealth NiFe70? I know we do see different resistances, different TCRs. But they're always in a rough ballpark that is very different to this wire in terms of both TCR and resistance.
We'll see. And of course I'll be emailing Crazy to ask. But we won't hold our breaths on that.
And when I heated this SS304 coil at 40W, it disintegrated in exactly the same way as the 'NiFe' did, and under roughly speaking the same amount of heat exertion (can only be judged very approximately, of course)
None of that might mean anything, maybe most wires look the same when they go above their max temps with a few exceptions like Titanium.
But if I'd picked this wire up off my desk without seeing a label, I would have said it was SS.
Is it possible that a NiFe70/30 wire could be so very different to Resistherm NiFe30, Kanthal NiFethal 70 and Stealth NiFe70? I know we do see different resistances, different TCRs. But they're always in a rough ballpark that is very different to this wire in terms of both TCR and resistance.
We'll see. And of course I'll be emailing Crazy to ask. But we won't hold our breaths on that.
It could be SS 317 or 317L (which has a little higher resistance than V2A/V4A). Its resistivity is like 0.8μΩm (6.4Ω/m for 0.4mm wire) with TCR around 0,00095/K, which would match your observations pretty well.
SS317 would make sense because Crazy Wire have a bunch of it. That's where I got my SS317 from in the past.
And christ you're right, the resistances match. I just checked on Steam Engine's Wire Wizard and 8 x 3mm wrap of SS 317 should be 0.648Ω. My coil read 0.63Ω. Close enough to be very suspicious.
So I suppose it's not impossible they simply chose the wrong wire / put the wrong label on it.
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