Is this how a decently built, used Ti coil should look?

[TrueNorthist]

This coil lasted over 100 hours and was actually still vaping well enough, but I am hoping you folks could cast a critical eye upon it and render your harshest judgement. It was one of my first attempts and had been abused a bit before I grew a brain cell and set the device properly.

The bottom (towards the deck)

and the top

It has been cleaned once this morning then vaped again all day today. I noticed one end is a bit clean and brownish, which indicates what, cold? Also, should it get dark blue like that? The hot-legs bluing occurred during tuning and they did not glow with the tweezers off and when test-fired with a wick and liquid. Ran it mostly at 450-470℉ and between 355 to 360 TCR. The wick got dropped down the drain so no pic, but it was soaked with darker liquid (the juice is clear in it's native habitat) with no black or dark brown anywhere but on the top outside of the coil. It's #24 Ti wire of unknown grade, likely 2 as it is very pliable, dull and grey when new, with no springiness at all. Used in a Kayfun v4 clone with sweet citrus 70/30 no nic.

edit: erm... I am starting to think this should be in the Ti wire thread? I accept full responsibility if it is heinously misplaced.

 

[J Wo]

I have no idea as yet to how TI should look as I have not attained any TI wire of my own, but the build quality is "coil porn" worthy. Nice twists... OOOOOHHHHH

 

[J Wo]

Oh and those legs too

 

[TheotherSteveS]

for what its worth looks pretty good to me. Shame you took it out!

 

[TrueNorthist]

Thanks. I was so blasted curious I could not stop myself rendering it asunder. I appears I can repeat it though, as evinced by the new build which is cooking with gas as I speak. I got a lot of experience building kanthal rigs and using this thicker wire makes it even easier. But I am seeing things I am unfamiliar with... The bluing for instance. And is the brown area from being a "cold" wrap, or is it from getting very hot? I just want to be sure I am not also gassing myself with exotic, oxidised metal salts.

Cheers peeps

 

[BigEgo]

When the thickness of the TiO2 layer increases (with heat) it changes the wavelength of light reflection from the metal which makes it appear various colors. You can tell by the color of the coil roughly how hot it has been fired. Blue is OK. It will eventually turn silverish/grey and after that you start seeing the white powder flake off. I will defer to druckle for a more in depth explanation.

In either case, as long as the coil stays "shiny" (as one metallurgist said), it should be safe.

 

[TrueNorthist]

When the thickness of the TiO2 layer increases (with heat) it changes the wavelength of light reflection from the metal which makes it appear various colors. You can tell by the color of the coil roughly how hot it has been fired. Blue is OK. It will eventually turn silverish/grey and after that you start seeing the white powder flake off. I will defer to druckle for a more in depth explanation.

In either case, as long as the coil stays "shiny" (as one metallurgist said), it should be safe.

That's a perfectly well detailed answer BE, understood. I will assume for now that the duller brown area is most likely due to a "cold" radius as it is not polished and shiny like the blue. I should run some tests at various temps to see what different temperature annealing does to this wire, but I will wait for the dna200 for that. Meantime I will just say no to silverish/grey.

Thanks pal.