I thought inkjets were thermal. Well, you learn something new every day!
If you ever build it, I think the customers will stampede to get their hands on one
The far less common IBM BubbleJets use a thermal system. Most inkjets are piezo based.
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The far less common IBM BubbleJets use a thermal system. Most inkjets are piezo based.
Yes Cheryl - you hit all 3 nails on the head
Burning deposits (or even inhaled deposits) are as a sparkler next to a bonfire, but all the same, let's make an LED version ...
I apologize if this point has been made, but...
Couldn't one just use a soxhlet, heated to the appropriate temperature, to attempt to 'purify' the juice to remove carbon-forming deposits?
Seems like a simple, cheap solution to me...
Couldn't one just use a soxhlet, heated to the appropriate temperature, to attempt to 'purify' the juice to remove carbon-forming deposits?
Seems like a simple, cheap solution to me...
The problem seems to be (though I haven't exhausted my experiments yet by any means,) that components of the solution slowly, but continually, degrade under heat. So you get deposits in distillation, and also in use (I'll try double/multiple distillation this afternoon, but I'm not very hopeful.)
Assuming the volatiles you're trying to extract are stable, a soxhlet will improve the yield effiency considerably compared to multiple distillations, but I fear if you ran it for long enough, you would oxidise all the nicotine away, and still have non-volatile breakdown products to gunge up the coil from leaf oils and other copmponents. Even ECOPure will blacken a coil (and that's just VG, nicotine, ethyl maltol, menthol and ethanol - which all ought to be entirely volatile.) I really don't understand it. There's some very strange chemistry happening in our atomizers!
With a regular still, the water vapour pressure seems to do an acceptable job of excluding free oxygen from the flask, but you won't get a steady positive pressure from a soxhlet, because it has to recondense repeatedly.
I suppose you could run the equipment in an inert atmosphere (argon perhaps,) to stop the nicotine oxidizing, but that's beyond my capabilities. If anyone has the gear for that, I'd love to hear how it works out, but I wouldn't put money on it being the magic bullet.
No mystery here: VG begins decomposing at a lower temperature than its BP. Although it is in a mix, with a nominal much lower BP, because of fractional distillation, enhanced by VG's viscosity and reluctance to vaporize, some will end up decomposing.
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And yet no acrolein found in the tests. I guess it's degrading to methanol and acetaldehyde maybe? but I am unable to find any degradation data for non-microbial decomposition - all the data I can find points only to enzymatic phosphorylisation (and that shouldn't be happening in our juice!) That's why I assumed it was fairly stable (at below the acrolein-formation point anyway.)
Have you got any data on what the thermal breakdown products from VG actually are (or might be)?
What gets me is, I bet smoke machine operators don't have all this trouble with atomizers gunging up and going 'off-vape' every few weeks. Is that because PG is inherently more resistant to thermal decomposition do you think, or is there something about the tiny, battery-operated form factor that makes the hardware suffer more? It's a shame noone makes a simple PG-based liquid like the ECOPure to compare it to.
EDIT: I now have some triple-distilled homebrew to experiment with in a clean atomizer. It'll take a few days to see if it's leaving as much of a deposit, but I'll vape it hard in work, and report back. It's noticeably a lot weaker nicotine strength (hardly had to dilute it at all - just a splash of PG.)
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VG decomposes to acrolein and water. Some of the acrolein perhaps polymerizes, oxidises or otherwise reacts, im maybe multiple steps to end up as a black deposit on the coil. Some probably is inhaled. As far as I know no test have been performed on VG-based juice vapor, and if they were, specific tests would probably be requred because as little as a few parts per million are harmful. VG decomposition is particularly lkely to occur on those occasions when the coil gets dry (and so hot), which is when the notorious 'bad smell/taste' is noticed.
In contrast PG leaves no deposit. See the test results for the experiment I devised, and carried out by Exogenesis, here (the contrast is startling):
http://www.e-cigarette-forum.com/fo...359-decomposition-vg-acrolein.html#post218472
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For ease of reference, post a couple of Exogenesis' photos here:
96% VG + 4% pure water (30ml); a little pure (distilled) water was added to thin the VG. After vaping this (equivalent to 2 weeks use), a brand new atomizer coil looks like this:
100% PG (30ml). After vaping this (equivalent to 2 weeks use), a brand new atomizer coil looks like this:
Source: http://www.e-cigarette-forum.com/fo...ple-cheap-effective-method-11.html#post211656
96% VG + 4% pure water (30ml); a little pure (distilled) water was added to thin the VG. After vaping this (equivalent to 2 weeks use), a brand new atomizer coil looks like this:
100% PG (30ml). After vaping this (equivalent to 2 weeks use), a brand new atomizer coil looks like this:
Source: http://www.e-cigarette-forum.com/fo...ple-cheap-effective-method-11.html#post211656
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It would be too difficult to try filtering out the vapor; probably impossible.
SurbitonPete has found that tiny bits of the deposit can get into the airstream and has experimented with a filter for these.
What is confusing me about exo's test pics ..is that 'all' of my dead coils have looked exactly like the coil that used the VG and yet for all that time I was using Juice that was mostly PG.
Hi Pete - The deposit is also formed from the dry-residue of the juice - various flavors and other additives or adjuvants that can not vaporise and are left on the coil to degrade. One of the worst type of juice for this is tobacco flavored juices; these leave a large residue of plant resins, oils etc (all the things that dissolve out of tobacco).
Yes I guess that's what it is but it's interesting that the deposit looks absolutely identical.
That's because after degrading in the heat of the coil, it ends up as mostly carbon, no matter what it was to start with (most of the dry residues being mostly organic (carbon based) substances).
I thought the intellicig test specifically looked for acrolein, and were unable to find any? But I can't find the link right now, and I have to go to work. I'll try to dig it out later.
Looks interesting, but I'll have to look at that later too.
While it's all very interesting, after 35 years of cigarettes and other substances smoking up my lungs I'm not altogether concerned. Some substance could be bed in there, but I'm betting not as bad as treated tobacco and paper smoke.
kinabaloo said:
Thats something I intend to test in the same way as the pure VG/PG tests.
i.e. pure PG (hardly any deposit) with an educated selection of Loranne flavours,
testing each flavour individually.
Objective is to test this anecdotal theory that oils > sugars > other additives > 'clean' flavours,
where > means probably generates more carbon gunk on the coil.
Nick, did you verify the pH of juice with litmus paper?
The pH meter I used to get pH8.3 was an old (gel filled probe),
but calibrated against standard pH4 & pH7 buffers.
The pH meter I used to get pH8.3 was an old (gel filled probe),
but calibrated against standard pH4 & pH7 buffers.
Might be easiest (quicker) to just do dry-residue tests. All the dry residue will be left to degrade on the coil.
Lifgt colored, artificial flavors such as vanilla and apple wll probably come out best, and tobacco flavors worst.
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Mt best guess re PEG is tha it will be between PG and VG but much closer to PG (a very small deposit level (from a marginal decomposition).
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It will br vary interesting to see if PG + pure nicotine leaves a deposit (through oxidation at least); if so, this may be one aspect that we cannot avoid unless another, possibly less effective form of nicotine is better in this regard.
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A thought on flavors:
A large part of what gives apple its taste is malic acid. This has a very high BP and will not vaporize in the atomizer. But a shorter chain mild acid such as acetic acid (BP 119C) could be used for the sourness (and work just as well ? - as sour is one of the five distinct tastes)
Researching into this thought, I found that the ketone damasceneone (vaporisable) will help create a better apple flavor, though is not itself a flavor (see link below).
Interesting article about artificial flavors: http://www.fks.com/flavors/tech/Science of Flavor Creation.asp
Scent is more important sensually to identification than taste. These are often volatile esters; chemicals that are scents are by definition easily vaporisable.
So, all the dry residue components of a juice contribute nothing to the taste and aroma (other than a burning taste/smell). It is possible to create most flavors using only vaporisable ingredients.
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