Stainless Steel mesh, Oxide discussion.

[Boden]

I want to know what Chromium Oxides are forming on the different grades of SS and at what temperatures.

I do know that when heated above 710degF the chromium starts to oxidize preferentially. When doing hot work on SS it is common OSHA standard that when welding, cutting and heating SS, ventilation must be used to prevent Chromium Oxide inhalation. Inhalation is the primary entry for chromium oxides and Hexavalent chromium is recognized as a human carcinogen via inhalation.^[2]

I am really hoping that the Chromium only reaches CRIII and not the more dangerous CR(V) and CR(VI). Based on the tutorials I have seen that heat the SS to glowing red 1500degF I am a bit worried . http://www.smex.net.au/reference/steelcolours.htm


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* Safety and Health Topics | Hexavalent Chromium

Hexavalent chromium can also be formed when performing "hot work" such as welding on stainless steel or melting chromium metal. In these situations the chromium is not originally hexavalent, but the high temperatures involved in the process result in oxidation that converts the chromium to a hexavalent state.

-----------------------------------------

* Ventilation and protection in welding, cutting and heating. - 1915.51

Welding, cutting or heating of metals of toxic significance.​

1915.51(d)(1)

Welding, cutting or heating in any enclosed spaces aboard the vessel involving the metals specified below shall be performed with either general mechanical or local exhaust ventilation meeting the requirements of paragraph (b) of this section:​

1915.51(d)(1)(i)

Zinc-bearing base or filler metals or metals coated with zinc-bearing materials.​

1915.51(d)(1)(ii)

Lead base metals.​

1915.51(d)(1)(iii)

Cadmium-bearing filler materials.​

1915.51(d)(1)(iv)

Chromium-bearing metals or metals coated with chromium-bearing materials.​

1915.51(d)(2)

Welding, cutting or heating in any enclosed spaces aboard the vessel involving the metals specified below shall be performed with local exhaust ventilation in accordance with the requirements of paragraph (b) of this section or employees shall be protected by air line respirators in accordance with the requirements of § 1915.154:​

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* http://doc.utwente.nl/69890/1/Langevoort87on.pdf

The oxidation rates of iron and chromium are of the same order of magnitude at
temperatures below 650 K (710 F). Subsequent oxidation results in an iron oxide on top of a chromium
oxide layer. At temperatures above 650 K the metal surface becomes enriched in chromium, which
is preferentially oxidized at these temperatures and pressures. Even prolonged oxidation does not
result in an iron-rich oxide surface. Nickel has never been found in its oxidized form. The binding
energy of oxygen, in the various oxide layers, is independent of the extent of oxidation and is
530.6 eV

*

The truth is I don't know. If anyone has done testing to see if the Chromium Oxides are contaminating the e-liquid we are inhaling I would like to know.

I have several samples that I am going to have tested by a independent lab. I will post the results of those tests here.

If anyone else does the same please post the results here.

If anyone has or finds research that would help please post it here.

Sincerely,
Boden

 

[Darthpistachio]

Interesting info and I'm bookmarking and subscribing - but I do have to point out one thing..

The release (possibly) of these materials will only occur when we are oxidising the wicks the first time after this inital time we will never really get the wicks anywhere near the red states ever again when in normal vaping operation - the only thing that will get that hot is the coil and that is another material altogether. -

The coil could probably never generate enough heat to get the SS mesh to that kind of colour - not without 'popping' in the process which in essence is what it is actually designed to do - bear that in mind..

 

[Boden]

Interesting info and I'm bookmarking and subscribing - but I do have to point out one thing..

The release (possibly) of these materials will only occur when we are oxidising the wicks the first time after this inital time we will never really get the wicks anywhere near the red states ever again when in normal vaping operation - the only thing that will get that hot is the coil and that is another material altogether. -

The coil could probably never generate enough heat to get the SS mesh to that kind of colour - not without 'popping' in the process which in essence is what it is actually designed to do - bear that in mind..

I agree that the creation of the oxides only occurs at high temperatures but those oxides then exist on the surface of the SS. The only way to reduce the CR oxides to a lower state is with a strong acid or a very long wait (about a year) in ph neutral solutions. If the chromium oxidizes to the CRV or VI state it may well end up in the liquid/vapor. The one ironic chance that the CR oxides reduce to III would be that nicotine loves oxygen and may act as a reduction catalyst. Although that reduction would have a very low energy and take much longer than most would be willing to wait, plus it would turn your liquid a rust color.

 

[Cyrus Vap]

This really needs a bump

 

[Jimi D.]

Subscibed..

 

[A.Jay]

If anyone else has more insight into this I would be very interested since I'm starting to get into RBA's a little now. I know, I know... I'm a little behind the curve on this, but I was dragging me feet when DCC tanks first came out too.

If I understand the process correctly, it is actually Chromium Oxide that we are shooting for to keep the coil from shorting out. The question comes down to, whether the oxide can be transferred to the juice or not. I personally am very hesitant to use any tank that is aluminum for fear of the health problems that aluminium can create. Whatever the case may be with using these wicks, I can easily say that it would be a very bad idea to inhale any of the smoke that is created while the mesh is oxidizing... not that anyone's doing that anyways right

 

[Cyrus Vap]

what I'm fuzzy on is what state is the Cr in on the mesh? meaning, you torch the living hell out of it, you end up with Cr that is now no longer bonded to the mesh and gassing off into your face?

Likewise, your vaping away on your mesh, say there's Cr(VI) hanging out there. Is it still bonded to the mesh/alloy? Or can it freely come off (touch, lick, lol...juice, whatever).

where is kurt

 

[A.Jay]

Can't say that I've ever licked my coils, lol.

But you bring up alot of really good questions that should be looked into more deeply.

An alternative to torching the living hell out of the mesh is to wrap some rolling paper between the coil and the mesh. Once you have the coil on there, light the paper on fire. That will leave a thin layer of carbon between the coil and the mesh. Downside to that is if your coil ever shifts on the wick, you're back to having shorts/hot spots.

 

[Jimi D.]

I just lightly torch the mesh. Do a couple of juice burns, and I'm good to go. No welding goggles included.

 

[Boden]

I'm still waiting for the second batch of lab results to come in. I fear that a sample size that would be conclusive and comprehensive under all the possible variations of alloy and temperature treatments is too large for me to afford. At 200$ american per sample this is getting pricy. What I do know is that the chemical composition of the oxides on the outside of the mesh is primarily composed of CRIV CRV and CRVI.

Understand that I am heating each wick then rolling it in my fingers like you would to tighten it up a bit, this provides enough friction to loosen some of the oxide in powder form into the liquid. Try it, torch a wick then over a piece of clean paper roll it a bit and see what comes off. (Do not inhale any of the powder that comes off, I am wearing a mask for this experiment)


Here I took the same piece of mesh and re-torched it, rolled it in my fingers for about 2 seconds and put some distilled water on it, the pics speak for themselves.




You couldn't pay me enough to vape that liquid.

The temperature to which the mesh is heated is directly proportional to the amount of each oxide that shows up in each sample. I've found no CRVI in samples that I heated in a oven at 600degF for 20 min. That seems to work the best and is the safest bet so far. Samples I heated to glowing red (+1300degF)... I wouldn't give to my enemies.

Another thing I'm testing is after oxidizing the wick, soaking the wick in vinegar for a few days then rinsing in distilled water. This should reduce any CRVI to one of the lower oxide states.

Honestly, I'm done with SS mesh, It's just not worth it and some of the ceramic and glass fiber options are just as good and without a doubt safer.

If anyone has any ideas please post them. I'm actually thinking of getting some aluminum mesh rolling it up and anodizing it. Theoretically it should be almost perfect non conductive mesh.

A.Jay,
Aluminum is only reactive in the presence of a relatively strong acid or base, weak organic acids such as those found in foods generally have little or no effect on aluminum. E liquid is pretty PH neutral so no worries there. Think of all the aluminum beer cans out there. Ever used aluminum foil? Alloys 1200, 3003 and 5005 Aluminum are food safe.

 

[Boden]

Can't say that I've ever licked my coils, lol.

But you bring up alot of really good questions that should be looked into more deeply.

An alternative to torching the living hell out of the mesh is to wrap some rolling paper between the coil and the mesh. Once you have the coil on there, light the paper on fire. That will leave a thin layer of carbon between the coil and the mesh. Downside to that is if your coil ever shifts on the wick, you're back to having shorts/hot spots.

One minor point; The point of using the paper trick is to keep the wire from scraping the oxide layer off while wrapping the coil ,once it burns, the ash (carbon) will be washed away by the e-liquid.

 

[Boden]

what I'm fuzzy on is what state is the Cr in on the mesh? meaning, you torch the living hell out of it, you end up with Cr that is now no longer bonded to the mesh and gassing off into your face?

Likewise, your vaping away on your mesh, say there's Cr(VI) hanging out there. Is it still bonded to the mesh/alloy? Or can it freely come off (touch, lick, lol...juice, whatever).

See the pics in my post above.

where is kurt

I have talked to him about this, He is really busy at the moment.

 

[gdeal]

Good point and thread Boden.

I noticed that "material" coming off my wicks when I first started gennys and doing a full oxidation process (torch,quench, torch quench, burn juice, rinse...repeat, etc.). I stop that practice when I saw degradation of the wick material. I now do not really oxide my wicks at all. I do torch lightly, (more for removing any residual oils after washing), but based upon your chart it seems to only be around the purple level. My wick color left me scratching my head until I saw your chart. lol

Unfortunately there is "consensus" that you need to oxidize the @#$ out of the wick in order to eliminate shorts. This is really just a band-aid that can be eliminated with good technique and practice.

Here is recent setup I put together about a month ago The second picture is after 75mls and full clean (dry burn and quick brush off), still dry. I just did another clean tonight after another 50 mls on top of that 75 but started vaping on it as a read this thread. After each cleaning, my wick still looks the same and shows no signs of kicking off that material you showed earlier. I think you can click on them to see a higher resolution version.

Looking forward to seeing addition lab results.

Initial:


After 75 mls:



After 125 mls:

 

[Cyrus Vap]

Boden I thank you for bringing this up and pursuing it further, we're all indebted to you

Can you tell us more about what you've done exactly?

It seems you oxidized a few wicks and sent them off to a lab for testing? Were the wicks also lit on fire with e juice etc, or just torched? Did they just analyze the 'dust'? etc.

This could indeed be a death blow to SS as a wick material. And here I was just worried about sililca lol.

 

[greenman]

Subscribed, also thanks to Boden for starting the tread.

 

[chet]

subscribed...!

 

[100%VG]

I want to know what Chromium Oxides are forming on the different grades of SS and at what temperatures.

I do know that when heated above 710degF the chromium starts to oxidize preferentially.

Boden

Hello everyone,

Please excuse me if I’m oversimplifying, as I honestly am not talking from experience, but…

I’ve been watching tons of Videos, and when making SS Wicks, some people don’t oxidize the whole wick, some people only oxidize the Coil Area, and other don’t oxidize with the Torch at all, relying on the Juice Burn and the Cigarette Paper Trick.

So, couldn’t you just nix the whole Torch Procedure altogether?, and do something like this…

SS Mesh/Cotton hybrid wick - YouTube from Quigs’ Hybrid Procedure, and wrap the Coil Area with Thread? .You could even double it up.

Whether you like a Very Dense, Tightly Wrapped, No-Center-Hole Wick, like BJ43 came up with and advocates, or one with a Center Hole, just roll it, wrap the Coil Area with Thread, Wrap the Coil, and be done with the whole Chromium Oxide thing.

Concerned about Manufacturing Oils and Contaminants? .At least one of you has already said you Boil it, so Boil the Snot out of it.

Want a little oxidation? .Do the Juice Burn 3-6 times.

Want more Coil Insulation? .Double-Wrap the Thread.

Need better Wicking? .Use #500 SS, or even #635 SS.

..
#500 SS Mesh... for Dense No-Hole Wick, wrap...............................
about 93.3mm into a 1/8” (3.18mm) slot/hole
about 88.2mm into a 3.0mm slot/hole
about 81.6mm into a 7/64” (2.78mm) slot/hole
about 73.5mm into a 2.5mm slot/hole
about 70.0mm into a 3/32” slot/hole
about 58.5mm into a 5/64” (2.0mm) slot/hole
about 50.0mm into a 1/16” (1.59mm) slot/hole
about 44.0mm into a 1.5mm slot/hole (Vivi Nova without modification)

Bias Cut only for U-Shape Wick​

No Center Hole? .No Problem.

Single Wrap – Hold the thread from the Middle of the Wick to the Top, and start wrapping Down on top of the thread, and tie it off to itself.

Double Wrap – Start wrapping from Lower to the Top, then back Down around that, and tie it off to itself.

Please forgive me if I’m .... Naked Wrong.. .I’m not vested in the Torch Burn Procedure, so I’m able to see this from a different perspective. .I just hope I’m right about it!!! .Maybe it's just this simple.

I’m going to bed shortly. .I’ll see if you laughed at me tomorrow.

 

[zippersnapper]

Good thread indeed. gdeal: That looks like "ribbon Kanthal". Would that be correct?
If so, and from what I understand, its pretty impervious to forming hot spots.

 

[Cyrus Vap]

I'm not laughing VG, I agree with you, so long as one is not made nervous by using cotton or the like as a wick, that effectively solves the problem and bypasses the oxidation

As far as using SS on its own...

Myself and a few others have voiced concern about the crud that seems to accompany mesh a while back. We've all seen it rubbing off on our fingers or backwashing into our tanks to some extent or another.

Unfortunately I totally misinterpreted the crud. I thought it was just charred juice, "carbon" etc. Which of course isn't good, but seems like health food compared to what we're talking about there.

So I had similar thoughts to VG last night before I crashed:

Relying on the juice burn- I suppose the concern there would be whatever oxide layer the scorched juice gives rise to. I'm guessing its mostly, if not entirely juice crud, as IIRC the mesh never really begins to glow during that process (to be honest I don't do it anymore so I can't remember).

Relying on the paper trick- If we totally skip wick oxidation we're using the burnt paper here as the oxide layer. Again we're dealing with burnt crap which is never good for the lungs, but seems much less concerning than Cr(VI).

Just oxidizing by pulsing the coil with juice...I've pulled this off once or twice on an unoxidized wick and its a PITA. Again I'm guessing when it works the oxide layer under the coils only amounts to burnt juice, unless you run a few dry burns which may get the underlying mesh hot enough to liberate Cr etc.

Using pyrex as an insulator comes to mind as well, but I never followed that thread or tried it, and don't want to rabbit trail this thread so I'll just mention it.

Another thought is, the problem seems to be the powder...the black powder... (this is turning into an X files episode lol). Can it just be flushed away with something? I'm assuming not, but hey, someone needs to ask right? Or would flushing it away effectively remove the entire oxide layer? Is the entire oxide layer just this black powder?

OK I'm going to work, later gents

 

[budynbuick]

FWIW, I took some temps on the SS coil & with properly wet coil (smoke,no hot spots) the temp doesn't pass 200F. Since the flash point of nic is 203F I would think 200F is well below the threshold for the formation of any toxic gas. Would like to know for certain. Used a +- one IR.