SS TC build advice please

[schlinky]

I got an evic mini recently and today some SS wire arrived so I'm about ready to try my first TC build!!

My plan is to put the EVic into Ti mode and drop the temp right down, apparently that should work but what sort of resistance should I be looking for from the coil? Btw, I got some .3 and .5

Any ideas would be good, thanks!

 

[schlinky]

So no one else tried this then? Must be just me

I made a test coil, put 15w through it (TC off) for about half a second (a few times) and it turned a bronze colour. Took that out.

Made another coil and was really gentle with the power, it didn't like that either and started discolouring, took it out.

Made a 0.8 spaced coil, didn't dry fire it, wicked and juiced & set it to Ti TC.

At 210f (18w) TC kicks in immediately, at 230f it creates a warm vape that limits itself. No discolouration to the coil although I'm not sure if it tastes 'right' but then I've never been below 1ohm before so I haven't got a great frame of reference.

 

[Beastie]

Not tried this myself as mt next TC wire will likely be the Niffy from. Stealthvape. This pic shows the equivalency temperatures according to steam engines wire wizard.

 

[schlinky]

Well I know a lot more than I did yesterday.

I didn't know all coils 'off-gas' to some degree, I didn't know that the discolouration was oxidation (it's not something I've ever noticed with Kanthal). I didn't know how bad dry burning was for the chemical composition of the wire.

What was interesting was finding out loads of people were using stainless steel wire without realising (G-Plat) so there were plenty of videos where I could see the oxidation of SS.

I guess mentally I was perceiving TC as something different to regular vaping, like a different kind of power or something (I'm not really sure what I thought tbh!) when in actuality it's just regular vaping that regulates itself. (well, duh! Like I said for some reason I'd made a distinction)

What I discovered made me even more cautious of using wire with nickel or chrome and validated my choice of going for 304 against 316/7. I also should have picked up some Ti wire

I also learned that using SS in Ti mode is little more than a proof of concept without the correct profile. Given the low change in resistance as the wire heats up means the 'resolution' or fine control of temp simply isn't there for it to be usable.

The flavour still isn't right with SS, there are two factors that differ from my usual setup, the wire material and the fact it's a spaced coil over a micro coil.
I saw plenty of people loving the G-Plat saying it was cleaner etc but for me it's just not right, less flavour with a twang of something.

So really I have more questions (but more knowledge) than I started with. For example what role does oxidation play in a wire? Do you need a little to prevent off gassing of the metal nasties? If you create a lot of oxidation and then break that seal it seems to be even worse so dry heating of wire should be kept to an absolute minimum. Dr F suggests not heating the wire at all but then are you missing that protective layer of oxidation?

Listen, I know it's still a lot better than smoking and it's best not to stress over the minutia until proper testing is done but I like to try and understand as much as I can about things so if you've got any input let me know

 

[danb]

I also learned that using SS in Ti mode is little more than a proof of concept without the correct profile. Given the low change in resistance as the wire heats up means the 'resolution' or fine control of temp simply isn't there for it to be usable.

Yeah, both Ni and Ti equivalents of 200 ^oC for SS are well below what you can set on a mod in Ni or Ti mode. You need something with an adjustable TCR to use SS for TC.

If you can adjust the TCR, resolution is not a problem provided you don't build too low. As a guide, a 1 Ohm SS coil (TCR about 0.001 K^-1) responds to temperature change by about 1 mOhm/^oC, which is plenty for accurate TC - it's comparable to a 0.14 Ohm Ni200 coil in terms of resolution). I'd guess if you build below 0.5 Ohm with SS, you might start lose enough resolution to get erratic behaviour in TC mode, but this is a theoretical prediction, it depends on how accurately these devices can measure resistance, I've not tried it in real life.

 

[schlinky]

Yeah, both Ni and Ti equivalents of 200 ^oC for SS are well below what you can set on a mod in Ni or Ti mode. You need something with an adjustable TCR to use SS for TC.

If you can adjust the TCR, resolution is not a problem provided you don't build too low. As a guide, a 1 Ohm SS coil (TCR about 0.001 K^-1) responds to temperature change by about 1 mOhm/^oC, which is plenty for accurate TC - it's comparable to a 0.14 Ohm Ni200 coil in terms of resolution). I'd guess if you build below 0.5 Ohm with SS, you might start lose enough resolution to get erratic behaviour in TC mode, but this is a theoretical prediction, it depends on how accurately these devices can measure resistance, I've not tried it in real life.

Thanks Dan, I'm sure a SS profile will come with the next firmware for the evic mini. Now that I've learned a bit more about Ti I'm less hesitant to try so I'll be experimenting with the reel that arrived today.
From what I read on my travels, with the correct TCR SS is perfectly usable with TC although it may be up to 30 degrees out so it'll be good to try that too when joyetech release the updated FW.

 

[danb]

Now that I've learned a bit more about Ti I'm less hesitant to try so I'll be experimenting with the reel that arrived today.

A good alternative to Ti (on paper) is NiFe48 (= Nifethal 52). I have some coming in the post from Germany and will share my opinions about it soon.

NiFe48 - Zivipf Onlineshop

 

[Jugg1es]

A good alternative to Ti (on paper) is NiFe48 (= Nifethal 52). I have some coming in the post from Germany and will share my opinions about it soon.

NiFe48 - Zivipf Onlineshop

Why didn't you order from stealthvape [emoji55]

 

[danb]

Why didn't you order from stealthvape [emoji55]

Because they don't sell NiFe48.

 

[stonesy]

On my RBA I've got some 317L using the csv from steam engine and it works great, the only thing I don't like is the consistency of the temperature; on the graph it's fluctuating about 10-15 above/below the temp I've set.