The hot loop of doom

[hazarada]

In the end, all of my genesis coils end up with a "hot loop". Sometimes it takes just a month, other times almost a year but eventually it happens. Its like a hotspot but instead of a spot, its an entire loop. Usually either the first or second from the top but i've seen it lower down a few times too.

The doom bit is that unlike a hotspot, I can't fix it. No amount of tweaking or reoxidizing will make it good again. I suspect its some kind of degradation of kanthal or maybe slight variations across the coils temperature end up morphing the material unevenly so it gets amplified or whatever. Thoughts?

 

[State O' Flux]

I suspect its some kind of degradation of kanthal or maybe slight variations across the coils temperature end up morphing the material unevenly so it gets amplified or whatever. Thoughts?

Yep... Kanthal wears out, and your suspicion I'd not only be willing to agree with... I might even shed some light on.

We don't seem to discuss it, here in the vape community, because the wire we use and lengths we use it in are relatively inexpensive and more easily considered expendable... but it's discussed fairly often in the hobby furnace and kiln community, where depending on temperatures used, Kanthal A1 wire may only see 40-60 life cycles to failure.

Kanthal has a life span based on a variety of variables, but most of those variables can be contributors to a known cause of failure. Once the aluminum oxide content, and the oxidation resistant, off-white alumina outer "skin" diffused from it, diminishes to the point where all that remains is a gray-black iron and chromium oxide skin... exposure/contamination degradation, inconsistent heating and ultimate wire failure will occur.

What are the contributors to Kanthal failure for the vape community? I doubt anyone has taken to close a look, so I'll theorize for now. Lets consider - the processes and applications of the end user, and the quality and condition of wire... as two for discussion.

Theory: Wire used with SS mesh and rope wick appears to have a shorter life span than that used with softer wick materials. The abrasion of metal wick materials against wire... as dissimilar metals, with different heat exposure temperatures and rates, expand and contract against one another.

Theory: There seems to be a growing amount of unlicensed, "fake" Kanthal out there... the metallic composition and ultimate lifespan of which, is an unknown. Uneven alumina distribution? Thin layer inconsistencies?

 

[v1k1ng1001]

I rebuild mine every few weeks so this is the first I am hearing of this. Good incentive to keep at it!

 

[edyle]

In the end, all of my genesis coils end up with a "hot loop". Sometimes it takes just a month, other times almost a year but eventually it happens. Its like a hotspot but instead of a spot, its an entire loop. Usually either the first or second from the top but i've seen it lower down a few times too.

The doom bit is that unlike a hotspot, I can't fix it. No amount of tweaking or reoxidizing will make it good again. I suspect its some kind of degradation of kanthal or maybe slight variations across the coils temperature end up morphing the material unevenly so it gets amplified or whatever. Thoughts?

Thermal conduction between that loop and the mesh; the other loops are conducting better with the mesh so not getting as hot.
If you coil it more compactly (microcoil) it should be less likely to happen.

 

[DaveP]

I just bought a Smok RSST pyrex tank atty and brought it home, coiled it, and installed a 350 mesh wick. My wick was an overly snug fit that required light twisting to get it to go down to the bottom of the tank. I'm sure the tight wick is why it isn't quite what I expected in terms of flavor. I brazed the mesh with a torch before rolling it and the size I cut filled the wick to the center when rolled tight enough to slip through the coil. That may be another reason it's under par compared to my Aspire Nautilus. Funny, the coil measured about 2 ohms on my meter before mesh installation, but read 1.1 and rose to 1.4 ohms after a break in. That must be the effect of a snug mesh wick against 28ga Kanthal.

This is a project that I look forward to perfecting. I really like the ease of re-coiling and wicking. I could get into loving this tank.

 

[Rickajho]

Heck with the gennys, I'm seeing this more and more on recent Kanger coils as well. First dry burn will reveal a "loop of doom", always on the outside edge of the coil. As in the OP's case tweaking won't correct it so I'm beginning to suspect Kanger quality control, when it comes to their supplier of kanthal, is going down the tubes. The real Kanger coils - not knockoffs - sure don't last or function like they used to. Getting really tired of seeing that superhot loop in there on first cleaning.

 

[DaveP]

I played with my new RSST quite a while yesterday. I removed the mesh wick and burned it with juice using my micro torch until it was nice and charred. Still, there's that nasty metallic taste. I'm beginning to think that mesh is way too picky and technique oriented for me. I want a wick that can be installed and vaped right away.

I thought that the problem might be wick size. It was a fairly tight fit to start with. I unrolled it and snipped off a section and turned it into a slip fit, but with no flavor increase. I'm still getting steel mesh taste with good vapor production. I guess more experimentation is necessary.

Soon, I'll probably give up and try a 3mm silica wick with a single mesh wrap on the business end.

 

[Chelonian]

I played with my new RSST quite a while yesterday. I removed the mesh wick and burned it with juice using my micro torch until it was nice and charred. Still, there's that nasty metallic taste. I'm beginning to think that mesh is way too picky and technique oriented for me. I want a wick that can be installed and vaped right away.

I thought that the problem might be wick size. It was a fairly tight fit to start with. I unrolled it and snipped off a section and turned it into a slip fit, but with no flavor increase. I'm still getting steel mesh taste with good vapor production. I guess more experimentation is necessary.

Soon, I'll probably give up and try a 3mm silica wick with a single mesh wrap on the business end.

I have good luck with wrapping the looped end of the mesh with cotton. It goes mesh - cotton - kanthal.

Gets rid of that nasty taste

 

[Rule62]

Even with mesh gennys, which I'm a big fan of, I can usually bump out the hot loop with a little tweaking using a mini screwdriver. Sometimes it takes a few minutes of moving the coils up or down, but I get them back to glowing even eventually.

 

[hazarada]

I have good luck with wrapping the looped end of the mesh with cotton. It goes mesh - cotton - kanthal.

that sorta defeats the purpose of a mesh wick - longevity

Truth is, ss wicks take a long time to get going. You'll be tasting metal for the first few days and they wont reach their best until at least a week in.

Even with mesh gennys, which I'm a big fan of, I can usually bump out the hot loop with a little tweaking using a mini screwdriver. Sometimes it takes a few minutes of moving the coils up or down, but I get them back to glowing even eventually.

Yea I've tried that, doesn't work for me. What you suggest would work if there was a hotspot kind of problem but I'm sticking to my original theory. The next time i encounter it, ill unwrap the coil and glow it without the wick, if the section still glows brighter then the rest of the wire I'll have my proof.. or disproof, we'll see.

 

[DaveP]

I'm playing with my first RSST in my spare time while getting the good vapes from my Nautilus. I pulsed my coil and got nice even glow from a tightly wound micro coil. I didn't check it after installing the mesh. Maybe I have a hot spot. I'll have to empty the tank, dry out the coil, and check it for hot spots with the mesh in place. Maybe I'll just wind a new coil and start over with the torch and burn it black again.

I rolled my wick between my fingers the other day until it was tightly wound and a really loose fit in the coil and then rolled it onto a cotton ball until it built up a layer like thin cotton candy that filled the gap to the coil. I wet it with juice, installed it, and vaped. Still wasn't impressed. The learning curve is a little steep on these things, but I guess I'm in for some really nice flavor when I get it figured out.

 

[Chelonian]

Wicks never make it much more than a cohple of months with me anyways.

I misunderstood your question....i thought that you were inquiring as to the hot loops in the first few firings after the build is fresh.

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[PaulBHC]

DaveP I just got an RSST as well. I'm using twisted cotton ball until I can get a torch. From what I gather (pbusardo and others) the air hole is too small at 1mm. Most people go to 2mm or 5/64.

 

[DaveP]

DaveP I just got an RSST as well. I'm using twisted cotton ball until I can get a torch. From what I gather (pbusardo and others) the air hole is too small at 1mm. Most people go to 2mm or 5/64.

I agree about the air hole. My Nautilus is like sucking through a big straw. The RSST is more like a tiny drink stirrer. 2mm sounds about right. Still, getting through the initial metallic taste of the ss mesh wick is tough vaping. I've torched mine to black with little reduction in the metal taste. Cotton wrap around the end helped, but I agree that cotton makes it a wick that you have to renew and fool with periodically. SS mesh is supposed to last a while.

I bought my micro torch at Harbor Freight for around $8 on sale. They all say to use triple filtered butane, but I'm finding that Zippo or Ronson work great. I like the one handed operation of the HF torch. You can pick it up with one hand, turn the gas control, and click the spark button easily while holding the mesh with the other. For filling, I just periodically give it three seconds on the filler can and use it. A week later, it still has plenty of pressure for doing short jobs. All of them have user comments about overfilling, so I just do the 3 second fill as needed and avoid overfilling.

 

[hazarada]

btw you don't need a torch or any flame at all, pulsing will work just fine

 

[Chelonian]

I have had good luck out of avoiding the SS taste by vaping a few hits...say ten.
Then i let the tank sit for three or four days.
Wont work unless you have a few tanks, and i found this out by not wanting to bother with breaking the mesh in...that taste...urgh.
Then i set my pro atty aside after loading it with the last of my chamberry from vapor chef.
Was so disgusted by it, as it was thr last of the juice. A few days later....a good surprise

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[classwife]

Moved to Rebuildable Atomizer Systems from APV Discussion