Stainless Steel mesh, Oxide discussion.

[redeyes24321]

Just thought i would throw something out there... Why doesnt someone go get their urine or blood tested for chromium? If we're vaping it at high enough levels for it to hurt us it would be detected in those tests. It stays in your sytem for 120 days at high levels. Small amounts of chromium is fine and is actually something the body needs to break down certain sugars, yes even chromium(IV).

 

[comptechltd]

Just out of curiosity has anybody tested to see if chromium is released from NiChrome wire??

Steve

 

[B2L]

I have to give it up to Boden again, if nothing else I've learned that I really don't need to be flaming my wicks at ALL

I just set up my ZAP on my provari, not a cro mag of a mechnical. 1.4 coil, literally took 10 seconds of pulsing for it to lock in its vaping at warp speed right now, pretty funny. For anyone on the fence, just try it!

OK, I tried it. 635 mesh with a .9 ohm 3/4 wrap, washed and boiled the mesh and inserted it into the coil (mesh cuts in the crease of your finger hurt more than paper cuts btw) Using a DID on a Poldiac mech mod. Pulsed a couple of times and it vapes like a champ, better flavor than I was getting from oxidized and no issues so far.

 

[Boden]

I am sorry, I could only get about half way through this thread before throwing in my 2 cents before going to work.
If this has already been brought up, I apologize.

I have seen various statements on two different techniques that may be combined to side step this problem all together.

- A ceramic coated coil has merit, but it has been observed that it may be too friable; causing problems with released particulates.

- A SS wick that has not been oxidized at all, shows to be doable after some fiddling with burning juice on the coil.

Would it not work better if the wick received a light ceramic coating? It seems to me the coil is too flexible to be a stable base
for the ceramic, maybe the wick would be rigid enough to prevent the ceramic from cracking.
Or, maybe there is some kind of carbon coating we could apply to the wick from a secondary source.
I seem to remember some articles about using electroplating to bond a thin layer of carbon to an existing structure.

You are correct about metal being a bad base for ceramic coating. It would expand when heated and the ceramic coating would just fall off.

I don't think coating a wick in Carbon (which would have to be graphite) would be a good idea. Carbon is a really good conductor. Carbon anodes are used in electroplating but the carbon is not the thing that is being deposited on the cathode, that would be a dissolved metal in the solution. The carbon anode is a non-consumable in the process, it just sits there delivering electrons to the solution.

From wiki: Electroplating is a process that uses electrical current to reduce dissolved metal cations so that they form a coherent metal coating on an electrode (cathode).

From what I understand, the original purpose in torching and quenching a wick was to build up a layer of carbon for insulation.
Hence, the admonishment to use the orange part of the flame and not the blue. The juice burn was to "season" that layer of carbon
so that it would not effect the flavor of the juice; much the same way as you "season" a cast iron skillet.
Somehow the preparation of the wick has evolved from using the flame to deposit carbon on the wick to heat treating the mesh to form an oxidation layer.

edit: How oxidization works: removed because it is too complex to describe easily
.
Ref:
HowStuffWorks "Oxidation"
Conductors

There will be some carbon precipitation to the surface but it is a very good conductor so not really what you want. Plus most of the carbon that precipitates to the surface will be bonded to one of the metals. The rest will be graphene. I'm not sure where the concept of oxidization building up a carbon layer came from, maybe it's because the oxide layer is dark and carbon is black, I don't know.

Maybe I am just rambling; after reading through this, I realize I may not even be on topic.

One last thought; has there been any consideration that insulating the wick from the metal parts of the tank would eliminate
most of the problems from shorts and hot spots? You know, path of least resistance, and all that.

Unless you rased all the metals to the fully oxidized state (which would be very bad), they are going to be a conductor/semi conductor no matter what you do. Some of the electrons will move between the wraps on the surface of the wick causing partial shorting. That said putting some sort of ceramic or glass insulator around the wick hole could help if the path is from the top of the coil (+) to ground. Keeping the coils loose around the wick is probably the best way to stop shorting as e-liquid is a very very poor conductor. The AL2O3 that forms on kanthal is also a insulator so that helps as well.

 

[Boden]

I just looked up Carburizing SS to see if it would somehow produce non conductance... The short answer is no, quite the opposite really. The long answer is here: http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA553029

 

[VpnDrgn]

Well, I had all that completely backwards.

So all we need is one of you smart guys to invent a polymer - glass alloy.
It would be flexible enough to make a mesh that could be rolled up,
and strong enough to be heat resistant and totally inert to all acids and solvents.

Maybe that is what is in Raidy's secret atomizer.

Ok, snap to it.

 

[bmarley5780]

Basically:

-Wash SS mesh in hot soapy water (dish detergent)
-Rinse
-Dry
-Put on gloves
-Wrap coil on drill bit and install
-Roll cleaned mesh and insert
-Press the button on/off numerous times at low voltage
while keeping it wet with water.
-Work out hotspots.

 

[Jimi D.]

I set up an unoxidized wick last night. Worked out great, but then I tightened the top coil. Shorted out. I came home today. I straightened out the coil with the drill bit I used to make the coil with. Pulsed the coil, and all is working great now. I think it's how the coil sits to avoid shorting on the wick. We never had to burn the living hell out of the mesh in the first place.

 

[Atlantisboy]

Jimi can you elaborate on "how the coil sits " please. Thanks.

 

[silversx]

yup.. did my first uncooked untorched wick and it's freaking awesome.. pulse pulse and done.. why were we torching in the first place lol

 

[dankcincy]

I havent read any of this but a friend on another forum has and wanted to post this but couldnt, Dont shoot the messenger please.


https://www.google.com/search?q=oxid...en-US:official

Let me put your fears at ease. There is no evidence Cr(VI) can be formed when oxidizing stainless steel at any temperature achievable with a small butane torch (up to 1700K, 1400C, 2600F). Depending on temperature, the main species are Fe2O3, Cr2O3, and a combination of spinel oxides, including MnFe2O4 and MnCr2O4.

Here's the most relevant and easy to understand peer-reviewed publication I found on the topic:
http://hal.archives-ouvertes.fr/docs...199303C935.pdf

As a side note, the only information I could find regarding hexavalent chromium resulting from heating stainless steel is a speculative statement in 29 CFR OSHA 1910. That association is NOT science, does not reference any sources, and is not meant to be interpreted as fact. It is a speculation of theoretical risk that provides a basis for requiring monitoring of potential occupational exposure."

 

[MikeE3]

I havent read any of this but a friend on another forum has and wanted to post this but couldnt, Dont shoot the messenger please.


https://www.google.com/search?q=oxid...en-US:official

Let me put your fears at ease. There is no evidence Cr(VI) can be formed when oxidizing stainless steel at any temperature achievable with a small butane torch (up to 1700K, 1400C, 2600F). Depending on temperature, the main species are Fe2O3, Cr2O3, and a combination of spinel oxides, including MnFe2O4 and MnCr2O4.

Here's the most relevant and easy to understand peer-reviewed publication I found on the topic:
http://hal.archives-ouvertes.fr/docs...199303C935.pdf

As a side note, the only information I could find regarding hexavalent chromium resulting from heating stainless steel is a speculative statement in 29 CFR OSHA 1910. That association is NOT science, does not reference any sources, and is not meant to be interpreted as fact. It is a speculation of theoretical risk that provides a basis for requiring monitoring of potential occupational exposure."

Well I surely won't shoot the messenger but I will ask:

What the heck to the links in the google search have to do with CRVI?

What evidence specifically let's you (or your friend) say "let me put your fears at rest"? Can you be specific?

And - the 2nd link you posted gives me a page not found.

 

[junkman]

I havent read any of this but a friend on another forum has and wanted to post this but couldnt, Dont shoot the messenger please.


https://www.google.com/search?q=oxid...en-US:official

Let me put your fears at ease. There is no evidence Cr(VI) can be formed when oxidizing stainless steel at any temperature achievable with a small butane torch (up to 1700K, 1400C, 2600F). Depending on temperature, the main species are Fe2O3, Cr2O3, and a combination of spinel oxides, including MnFe2O4 and MnCr2O4.

Here's the most relevant and easy to understand peer-reviewed publication I found on the topic:
http://hal.archives-ouvertes.fr/docs...199303C935.pdf

As a side note, the only information I could find regarding hexavalent chromium resulting from heating stainless steel is a speculative statement in 29 CFR OSHA 1910. That association is NOT science, does not reference any sources, and is not meant to be interpreted as fact. It is a speculation of theoretical risk that provides a basis for requiring monitoring of potential occupational exposure."

I want to believe.

Give me some better links, please.

 

[DrMA]

Yey I can post here now!

And thanks dankcincy for passing on the info.

Here are the correct links:
https://www.google.com/search?q=oxi...&oe=utf-8&aq=t&rls=org.mozilla:en-US:official

http://hal.archives-ouvertes.fr/docs/00/25/23/74/PDF/ajp-jp4199303C935.pdf

and a Link to the OSHA 29 CFR
http://www.osha.gov/SLTC/hexavalentchromium/index.html

 

[junkman]

Yey I can post here now!

And thanks dankcincy for passing on the info.

Here are the correct links:
https://www.google.com/search?q=oxi...&oe=utf-8&aq=t&rls=org.mozilla:en-US:official

http://hal.archives-ouvertes.fr/docs/00/25/23/74/PDF/ajp-jp4199303C935.pdf

and a Link to the OSHA 29 CFR
Safety and Health Topics | Hexavalent Chromium

Link 2 and 3 still no good.

Link 1 is just search results. We need a specific source and preferably a quote within that source if you have it

May be due to my using my cell phone.

If the links are good, I apologize

 

[Cool_Breeze]

Link 2 and 3 still no good.

Link 1 is just search results. We need a specific source and preferably a quote within that source if you have it

May be due to my using my cell phone.

If the links are good, I apologize

Links 2 and 3 are good here.

 

[asdaq]

Links working, must be the phone junkman. Lotsa pages, we are gonna have to ask you to come home now and read them for us to give us a concise report.

 

[junkman]

Links working, must be the phone junkman. Lotsa pages, we are gonna have to ask you to come home now and read them for us to give us a concise report.

Ok, phone it must be....good, someone should have it all figured out before I get home!

 

[DrMA]

The first link is to Google search results for the phrase "oxidation of stainless steel at high temperature". If you're interested in the topic, spend some time reading thru the results. It's meant to show with some degree of confidence that the topic is well-researched and that none of the scholarly articles addressing this issue found hexavalent chromium in the oxide layer that develops on SS when oxidized at high temps.

The article by Guillamet et al. (1993) gives a detailed analysis of the oxides formed by oxidizing 304 and 316 SS at temperatures between 900-1100°C. Here's the abstract for those who cannot follow the link:

Stainless steels of type AISI 304 and 316 were heated in air (1-5-15 minutes at 900-
1000-1100C) and the oxide layers formed on the surface were analyzed by XRD, CEMS, SIMS
and FTIR. At these temperatures the main oxides are Cr2O3 and a spinel close to MnCr2O4
for polishing samples (with Fe2O3 for the chemically cleaned samples). The oxidation induces
a Cr and Mn depletion from the metallic substratum and a phase transformation gamma (f.c.c.) -> alpha
(b.c.c.) in a thin layer of the steels near the oxides - metal interface.​

For those who are not chemists, (Cr2O4)-2 is the chromite anion, a chromium(III) compound, which is extremely stable, not toxic, and widely found naturally in a class of oxide minerals in the spinel group.

 

[Calypso]

It has been a while since I've had a chance to get onto the ECF. I ran across this thread. It is a good read and important information but what stuck me the most was how we evolved from the original post from raidy who suggested using a lighter and heat the end three times the final time using some juice to nuking the entire SS wick until it is black giving off some kind of particles. This sounds like the results of a game of grapevine. Personally I've found that lighting a little juice where the coils go once will provide enough protection for the kanthal.