Cotton Test

[cobalt327]

Elsewhere I read a (rather old) post by Jaquith that said in part:

...disable Preheat period (1,1, 0 seconds), set Power to 100W or more, set temperature to 470° F using scrap cotton and "cotton burn test" until light golden brown. Adjust TCR until passed.

DO NOT OHM LOCK!

 

Is this still what is used to check/dial in the TCR? BTW, I’m using an SDNA 75 so max watts would be 75w.

[bmclaurin]

Until someone more knowledgeable than I comes along...I guess that's true, but TBH I've never bothered with that. Just load up the .csv for whatever coil material you're using and vape on. As long as you're using standard TC materials, the .csv's on steam-engine are battle tested, and I've never had a problem with them.

And when I say "never had a problem with them," I mean that literally. We're talking tens of thousands (probably more) of hits, and never a burnt hit. Not even once. The very few times I've had hits that were obviously too warm, it was not TCR-related; usually it was because
of a loose leg or maybe an inaccurate cold ohms measurement or something like that.

[cobalt327]

The coil wire is mixed tc/non tc and while the values can be estimated using something like wire wizard, I want to fine tune using a cotton test.

[bmclaurin]

Gotcha. Nothing wrong with that.

[retird]

bmclaurin said:

Until someone more knowledgeable than I comes along...I guess that's true, but TBH I've never bothered with that. Just load up the .csv for whatever coil material you're using and vape on. As long as you're using standard TC materials, the .csv's on steam-engine are battle tested, and I've never had a problem with them.

And when I say "never had a problem with them," I mean that literally. We're talking tens of thousands (probably more) of hits, and never a burnt hit. Not even once. The very few times I've had hits that were obviously too warm, it was not TCR-related; usually it was because
of a loose leg or maybe an inaccurate cold ohms measurement or something like that.

There are a lot of folks that have/will run the "Cotton burn test".  Mixed wires may require a trial and error approach (cotton burn test). I never had the need or desire as dry and burnt hits were not/are not even something I experience at all since TC came about.   I don't use mixed wires.  The cotton/water test came about as those using a "new wire", that being Ti, were needing a better TCR than Nickel TCR gave them.  Nickel TCR was the only one available at the time as I recall.

I too guess the cotton burn test is true and also seek some knowledgeable/scientific explanation. Just two quick questions come to mind. Cotton of any kind/quality all burn at the same degrees F?  At what humidity level is that true/untrue, or put a different way, does humidity (moisture content of the cotton) effect the temperature at which cotton will burn?

[VapingBad]

IMO the cotton scorch test is great as long as you ridgy stick to a set fire time and the same brand cotton, I use 10 seconds as it should more than compensate for heat up time, let alone humidity or cotton water content, which I don't think is an issue personally.  Done like this you get a clear graduation, I like doing 20 F steps, sometime 10.  This is an old pic of Ni200 on a DNA 40, ignore the bottom one for the SX Mini that thing was way way off, the point is you have many degrees of scorch so if you use a new wire make a Ni coil of the same geometry and test both like this, then refine your TCR for the new wire. Note that only went up to 500 F as the SXM had set fire to the cotton, with a DNA I would up to 600 F and the shade is different for each temp, sorry I should do an up to date pic.
 

[cobalt327]

Excellent-thanks.