Sweet Spot Vapor Ti - Why the radically different curve for 0.4mm?

[teilo]

Can anyone explain why the TCR curve supplied by SSV is so radically different for their 0.4mm wire? It is almost as steep as Ni200.

I am building dual spaced coils 3mm in diameter, coming in at around 0.23? base resistance on the 0.4mm, and 0.17? on the 0.5mm. That's total resistance for both coils in parallel.

On my 0.4mm coils, I'm generally finding I have to back way off on the temperature, whereas when using the 0.5mm TCR or the steam-engine Ti TCR, it seems fairly close. As the coil ages, I don't have to back off quite as much.

I'm willing to grant that a different gauge wire will have a slightly different TCR curve, but not so different that it looks like a completely different metal.

The result is consistent on two different mods: the Wismec Releaux and the Madvapes Blacksmith.

[HugeEgo]

I don't think SSV knows what the proper curve is because what they are selling is not grade 1 titanium wire.  All of the literature I've seen for Ti TCR values relates to pure titanium and not these alloys.

Of course, it's possible they (or others on their behalf) have tested the wire at various known temperatures and resistances and charted the TCR, but I doubt it.

And TCR has nothing to do with the diameter of the wire -- it is an inherent property of the metal.

[mcvapes]

I actually talk with the man behind SSV quite often, and he has done the work required to plot out TCR of their Ti alloy. 

[Johan]

Work may have been put into that, but for me the SweetSpot .csv for the .4mm wire was a failure on dry burn test. I picked up a .csv that had been posted by Jaquith that works good for that wire. Tried to find it again here but no luck. I still have the file on my computer, but am too ignorant of file sharing apps to know where to post it.

[Viruk]

I can't remember where, but I've read somewhere that the SSV file for 0.4mm wire didn't work too well but I've read the 0.5mm file works well for both those wires.

I have some 0.5mm SSV titanium but haven't tried it out yet - I'll try to post some results here when I do build with it.

Johan - if all else fails you could just copy the contents of the file here, then anyone who needs it only has to copy and paste the text into notepad (or any preferred text editor), save it as a csv then upload to the device via escribe...

[Johan]

Temperature (degF)	Electrical Resistivity
-58	0.65
68	1
212	1.16
302	1.56
392	1.66
482	1.81
572	1.987
800	2.665

Never used Excel so this is all I can seem to get. Yes, kind of pathetic lol.

Jaquith, could you give us a hand here. It appears that the file dropper file has expired. Thanks

[Viruk]

you need the commas (,) in a csv (comma separated values) file...

Try the following if you're going to copy and paste into something like notepad and remember to save it as filename.csv (filename can be anything you like )  If you're using excel (or any other spreadsheet) it should add these in for you when saving as csv - as long as the data is in different cells.
Once you have a file saved you should then be able to upload via escribe

"Temperature (degF)","Electrical Resistivity"
-58,0.65
68,1
212,1.16
302,1.56
392,1.66
482,1.81
572,1.987
800,2.665

[mcvapes]

For what it's worth, he's updated the TFR curve for .4mm wire. 
http://www.sweetspotvapors.com/category_s/1856.htm