The Illusive Materials Thread

[TommyDee]

I keep seeing references to creating a thread that talks about materials but I couldn't find a one.

A recent discussion had me start a query into appropriateness of printed circuit boards in or near a vape path. I will note that the Flowermate CAP Beta project showed significant effort to make sure the PCB was isolated from the oven.

I ran across this absolutely stunning study document. I wasn't sure what I was looking for until I found this;
https://www.epa.gov/sites/production/files/2015-08/documents/pcb_final_report.pdf
If we had studies like this on other materials I would be happy to review them.

Basically, one of the compounds in most circuit boards is a flame retardant. I mentioned before that PCB's are rated 140'C with some unknown margin. Well, the upper end of that margin is well under 300'C as well.

Printed circuit boards exposed to elevated temperatures beyond their specifications are not necessarily hazardous. When I consider daily use of our devices, these little things do start to matter to me.

Anyway, this is not necessarily an intro for a discussion on PCB's as this is not an issue on most vapes. Rather, this is a place to finally have that 'materials' conversation we keep getting directed to.

 

[KeroZen]

Oh man I've been meaning to create that thread for so long. I've got a backlog full of references on many common materials we use but it's been sitting on the back burner for a while...

My initial idea was to have a "master thread" linking to a dedicated thread per material type. One would be for metals, distinguishing metals just in the vapor path as well as metals used for the heater itself. We have one for PTFE already I think, but we would need one for plastics in general or other sub threads. Silicone would definitely need its own thread as it's so prevalent. Even glass can have issues due to coatings and lead content, although I don't think it can really leach out but are we 100% sure?

I welcome your idea. We could perhaps even create a forum "resource" (article) whenever that thread yields something concrete and useful, say as a kind of reference / bible where we could redirect new users to when the discussion arises again and again as it does currently (with mods telling us this is not the right place to discuss the topic hehe)

 

[TommyDee]

That's it, @KeroZen . When we compile the data, it makes good pointers for relevant threads. An 'index' top level is a good idea. Let's see where this goes. Obviously, please contribute. Teflon and silicone are a pair I am particularly interested in. Plastics, rubbers, wire and coatings, bonding, etc... indeed.

 

[scy123]

I was interested in what people thought about plastics. I know in the early days of ecigs they used delrin as insulators for tanks. These insulators would be almost touching the heating element sometimes and even melt occasionally. That could not of been good. Now everyone uses peek insulators.

A lot vapes out there uses plastic, often mystery plastic. Sometimes even holding the element in place. I'm not against plastic, but interested to know what plastics would be considered reasonably safe.

 

[TommyDee]

This is a nice little bulletin on various Teflon formulations including PTFE;
https://www.plasticseurope.org/en/r.../108-guide-safe-handling-fluoropolymer-resins

How do we feel about PTFE around air paths?

 

[scy123]

We use ptfe tubing in 3d printing. These would be sitting on the hot end in some cases. Was told if it ever reached 500f it would be releasing toxins and if it ever melted would be releasing serious toxins. Was never a fan of it after hearing that. Though seems you can't escape the stuff now a days.

 

[Planck]

Teflon releases hydrofluoric acid at some elevated temp. This is an extraordinary nasty chemical. Within it's safe operation range PTFE is very stable and inert.

 

[TommyDee]

True... is the vaping range up to 240C safe? I've seen the mass loss chart but it starts at like 420C but it doesn't start at zero. It dives right in at 0.01%. That means mass loss begins at some point.

Of interest is the advice for workers to 'not bring tobacco products into a workplace' where fumes of flouropolymers were present.

I do know it emits some nasty shit when abused. Otherwise great stuff.

 

[invertedisdead]

How do we feel about PTFE around air paths?

 

[TommyDee]

 

[Planck]

How do we feel about PTFE around air paths?

If the air is hot around the PTFE I would not inhale it.
Several very reactive chemicals could be present, some are guaranteed to be present with the level in lock step with the temperature. No thanks!

 

[scy123]

Yea, it just seems off to me to have something that can become toxic at so close to the temps the heater will be operating.

Sorry, little off topic from the ptfe, but what about metals? I know 3 series stainless steel is good, but what about aluminum and copper?

 

[Planck]

what about aluminum and copper?

Aluminum I am generally comfortable with, there are so many alloys though I'd be looking up what the alloys are. Copper I have serious concerns with, it's not going in my mouth.

Many I expect will be uncomfortable with AL

 

[scy123]

yea, I hear big fuss about the volcano and aluminum dust. They are medically certified, so I have no problems with it, unless it was like a lot of dust.

In the early ecig days people would use a lot of copper cause they made it hit harder. I had a mod that was almost all copper....... talk about hitting off some toxicity.

Kinda gets me thinking though. A lot of alcohol distillers swear by copper..... This would be 90%+ heated alcohol steam running through the copper that they will be drinking. Now I don't know what to think.

 

[invertedisdead]

but what about metals

 

[scy123]

Yea, you would need metals to reasonably heat the element though. Could find nothing wrong with 316L SS, which is my preferred choice.

 

[TommyDee]

The problem I had with stainless steel was contact resistance. The contact points got very hot until I went with copper. After that, they remained warm to the touch but not hot. This has a lot to do with thermal conductivity. Considering the temperature elevation of the puck in the LB, this is not going to be a problem machining it directly from a copper rod. It is also a lot easier on the mill/lathe.

 

[scy123]

I’m kinda hesitant on the copper. A lot of my ecig tanks use SS for everything, so I know it could work.

 

[GetLeft]

So you all gonna organize things? Will the mods create a forum that can have separate threads? That would be the way to go because already things are getting random. Has anyone asked the mods?

 

[TommyDee]

As far as materials go, stainless steel is safe at vaping temps. Copper has never bothered me at reasonable temperatures under 150F.

An organized thread? Is that even possible?

 

[scy123]

I notice a lot of times manufacturers don’t list exact materials used. And when asked they say it’s proprietary information. They will often tell you what metals the bowl and heating element is, but the plastic holding the bowl and heating element is not disclosed.

 

[Concerned Mother]

So, here I am again wondering where this material safety thread is.

 

[gostavs]

Great thread!

I had an idea to make a ceramic oven for my dynavap when I saw a "aluminium ceramic thermal insulation tube". Then I saw a thread about a blacksmith that was on the waiting list for a lung transplant after working near and forge insulated with white ceramic wool.
Found this on aluminium oxide which i the main component of aluminium ceramic.


Anyone know if another ceramic would be appropriate as a tube in a IH ?

 

[TommyDee]

Alumina, which is aluminum oxide, is fired at super high temperatures. There is nothing left for us to off-gas with a mere torch.

 

[florduh]

Important to note when looking at industrial worker inhalation studies: unless you're grinding up vaporizer components and huffing them 5 days per week for years or decades, they're not really relevant.