That's interesting, I never really understood what it is that is supposed to provide electrical isulation to a torched SS mesh. Are these iron carbides, chromium carbides or both? And is it a known fact that carbides insulate, or is it just assumed that something must be doing it and carbides are a good candidate? Is it known if oxides have any role in insulating the mesh? I can't seem to find any solid info on the interwebnets.
Bear in mind that I'm not a metallurgist. I'm just an old welder, with experience in working with various grades of stainless steel. What I say may be subject to correction.
All stainless steel contains carbon, in various percentages, depending on the grade. When stainless steel is heated, the carbon in the metal begins to precipitate toward the surface. In most applications, aside from our purposes, this is something fabricators wish to avoid, because this carbide precipitation has a detrimental affect on the integrity of the stainless. This is why stainless steel, when improperly fabricated, will actually develop rust, in areas adjacent to welds which have been done without proper technique/procedure. It's due to the carbon, which has precipitated to the surface. The most critical temperature range at which this happens is between 800°F and 1400°F. The longer the metal remains within this range, the more of the carbon precipitates. This is why, IMO, it's better to not quench after heating. The quenching stops the precipitation, by quickly dropping the temperature of the material below the 800° threshold, where we want the carbide precipitation to occur.
For our purpose, we actually want this carbide precipitation to occur. As I understand it, this precipitated carbon is what provides the insulation layer on the mesh. As a side note, this is why L grade stainless is harder to oxidize than the non L grade. The L indicates Low Carbon. For example: 316L contains half the carbon content of regular 316. 304L contains half the carbon content of regular 304, etc. It's harder to oxidize because the metal only contains half the available carbon to begin with.
Now, I admittedly don't know anything about the Cr issues. But my feeling is that as long as we are oxidizing properly, by staying within the 800°F-1400°F range, and not over heating, stainless steel mesh is a safe material, for our purpose.
As far as ceramic, which I know nothing about: Why are some folks assuming that it's safe? Just because it's not stainless? Has anybody looked into the material? Are there binders involved that hold the ceramic together? It seems to me that rushing to a different material, just because it isn't the previously used material, without investigating the new material, is premature.
When you think about it, many of the ingredients and materials that we put together and use for
vaping, are materials and ingredients that were never intended for creating steam, and inhaling into our lungs. The flavorings we use in
juice, whether DIY or pre made, were intended for food, not for vaporizing. The
batteries we use were never intended for the abuse we put them through sometimes. Stainless steel was created as a non corrosive material; not to be deliberately corroded, as we are doing. Every time we vape, we are using a material for something other than for which it was originally intended.
