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Thread: making your own fog juice?

  1. #131
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    Quote Originally Posted by zorn View Post
    frying pans produced more acrolein than foggers and there isnt much incidents with using frying pans.
    While frying pans can produce acrolein in aerosol form, it's far easier to produce it in the food that is being cooked. Cooking bacon in a broiler will make acrolein too (in the fat of the bacon as it cooks).

    I think the reason he thinks that is because frying pans boil the oil all the time while in fog machine only the glycerin/glycol which is trapped in the heater might be boiled to the needed temperature, so even though oil produces less acrolein than glycerin there's less glycerin being boiled in a fog machine.
    Regarding the underlined portion (my emphasis), it's a whole lot less. Glycerin's primary decomposition product is acrolein. by comparison, glycol's primary decomposition product is either lactic acid or oxalic acid, depending on which ester of glycol you're using. The amount of acrolein produced by cracking glycerin (or cooking oil, for that matter) is far less than it is for glycerin. (The wikipedia pages for each chemical go into this in further detail, if you've got the organic chemistry background to follow it.)

    I don't have further numerical data on this (yes, I've looked), but if you're versed in organic chemistry you can look at the structure of glycerin vs acrolein and then glycol (especially any of the poly-glycol esters) and see how much more needs to be done to break it up to get to acrolein. Based on my experience, I'd estimate it at a minimum of 2 to 3 orders of magnitude more likely to produce an organic acid than acrolein.

    Isnt the .34 for "nasal (sensory) irritation", while "respiratory effects" is mentioned at 0.6?
    First, nasal irritation falls under respiratory effects. Second, as stated earlier in this thread, .34 ppm is 2 orders of magnitude above the AMRL for acrolein. This is why I'm skeptical of that link - it lists exposure concentrations that are much higher than any other source I've looked at. In fact, it's only a little more than 5 times below the IDLH level for acrolein. All the other links I provided (6 total, between two posts) show limits that are much lower.

    "The threshold concentration for the perception of acrolein vapour may be as low as 0.07 mg/m3". Excuse my englsh, i think hes saying thats around when you will "sense" acrolein?
    Again, every source I linked to above shows the smell threshold being between .25 and 1 ppm. .07 ppm is a ridiculously low number. If we were talking about ethyl mercaptan, I'd buy it, as we are horribly sensitive to sulfurous compounds, but acrolein is a simple aldehyde and there's no reason to think our nose would be especially sensitive to it.

    Maybe they found a "super-smeller" (alternatively, "super-taster") and used his/her sensitivity as the baseline? I don't know, but it doesn't jive with any of the other sources I found.

    I wasnt asking about acrolein scavenging agent specifically.
    Absent the presence of glycerin, there's really no need for an acrolein scavenger, since you wouldn't expect acrolein to be formed. In the case of a glycol-based fluid, the only thing you might want to add would be a weak organic base or an alcohol (such as PVA, which Steve mentioned above) to tie up any oxalic acid that might be produced.

    I think kecked said he didnt find any scavenging agent in the Rosco fluid.
    At the detection limit he was working at (.1 % to .5 %, which is 1000 to 5000 ppm), he'd never find it. Furthermore, as stated above, Rosco fluid should be glycol based these days, and if so, it won't need an acrolein scavenger. If they add something like PVA to the mix, it's going to be at super-low concentrations (a few ppm), so again, it will be a bitch to find unless you've got lab equipment with equally low detection limits. (Note that in the case of HPLC or GC, you also need a column that has been calibrated for the particular agent you're searching for. No mean feat when there are multiple scavenging agents that could be used...)

    do we have data how much acrolein and other harmful chemicals are produced by cracking of propylene glycol?
    Quantitative data on acrolein? No, I haven't found any. (There is some numerical data on the production of oxalic and lactic acid, but as mentioned previously, these aren't nearly as troublesome.)

    However, we do have qualitative data that shows the primary thermal decomposition products of both ethylene and propylene glycol. Acrolein is not listed there, although a number of organic acids are. (Again, the wikipedia pages for these chemicals has more information, if you can follow the chemistry.) Likewise, we have qualitative data for glycerin that shows the primary decomposition product is acrolein. (This is actually a valid production method for acrolein, but it's cheaper and more efficient to start with petroleum precursors as a feed stock.)

    This information allows us to say with confidence that Acrolein is definitely the major byproduct of thermal decomposition of glycerin, and it likewise is NOT a major byproduct of the thermal decomposition of glycols.

    Still will stick to propylene if it is higher but would like to know just how much safer it is.
    I can't give you a number. But I can say that given the choice between dealing with acrolein and oxalic acid, I'll take the oxalic acid. Neither one is going to be produced in large amounts, but it doesn't take very much acrolein to cause problems, where as oxalic acid is far less hazardous even in higher concentrations. That's the best I can do.

    Suggest you get together with Dream, Cypher0, and Magus and do some research locally. Maybe you can convince someone at a local university to work with you. Show them the fluids you've been using and see what they say.

    Adam

  2. #132
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    I MEASURED acrolein, formaldehyde, formic acid, acetaldehyde found none of them in the fog. I build a box and concentrated the fog onto a filter and then shot it into a GC. read my past posts. Found next to nothing. Did it with glycerine and pg. Tried PEG as well but that didn't make fog it just burned. Look it seems from what I found at least that it is not as easy to make acrolein in a fog machine as you might think. As I said before so long as the water is there it tend to stay at 212F. Now if you drop the amount of water in the mix your a fool because that WILL generate lots of acrolein as the glycol burns. The water acts to keep the temp down to 212F. It is under a little pressure so maybe a bit hotter in the chamber but not much. Look up a steam temp table. I doubt its under more than a few pounds of pressure.

    Just looked it up 100psi =337F
    10psi=239F

    Boiling for PG is 370F There is NO WAY you are getting to 100psi in a normal fogger so as long as the water is present your going to be ok. Now if the solution separates your in trouble......

  3. #133
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    Thanks for all the tests kecked.
    I second that you shouldn't drop the amount of water in your mix. Besides the reason mentioned, it's just pointless. 1:3 ratio already creates a very dense fog.
    As for the solution separating, if it is glycerin and water, then Clive gave a comment on that.
    Quote Originally Posted by BigClive View Post
    As an interesting note, I did a lot of experimentation with glycerine based fluids and common tap water (it's extremely pure in Scotland) and recently found the old 2 litre drinks bottles I mixed it in complete with light food colouring tints and a label stating the ratio. These bottles have been sitting on a shelf for OVER 30 YEARS! (I can hardly believe that myself!) and the one with 2% glycerine had a little mould/fluff floating in it, while the ones with about 10% or more glycerine were still crystal clear and had no smell to indicate any deterioration. They had also remained fully mixed with no separation of the glycerine and water after 30 years.
    30 years is a long time. Still, mixing your bottle before use just to be on the safe side won't hurt anyone.
    Last edited by cipher0; 06-17-2014 at 23:22.

  4. #134
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    Quote Originally Posted by kecked View Post
    I MEASURED acrolein, formaldehyde, formic acid, acetaldehyde found none of them in the fog. I build a box and concentrated the fog onto a filter and then shot it into a GC.
    Hey Mark;

    I read your post where you performed the test, but from your original description it sounded like you collected the fog in a box and then ran it through a solvent bubbler to capture the decomposition products. You mentioned that you would do the extraction later that evening, but you never posted the results.

    I figured you'd be running the sample on a headspace sampler. If you used a filter, how did you wash the organics off the filter to get them into the GC? Just curious...

    so long as the water is there it tend to stay at 212F.
    Completely agree. The risk of acrolein production is not present when the machine is belching out huge clouds of fog. The steam is going to be the major factor in determining the temperature. The risk is when the pump is off, the heater is at full temperature, and a drop of fog solution seeps into the heater and just bakes in there. In that case, you don't have a large volume of steam to hold the temperature down.

    Boiling for PG is 370F There is NO WAY you are getting to 100psi in a normal fogger so as long as the water is present your going to be ok.
    Again, agree 100%. But you won't build any pressure at all if the solution seeps into the heater while the pump is off. The water will boil off instantly, but there won't be enough steam volume produced to move anything. Then the rest of the organics just sit there and cook.

    Adam

  5. #135
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    I sucked the fog through a pvc filter like you use for asbestos. The fog condensed particles got trapped. I rinsed the filter with ethanol and ran it through a bead column. I also used draager tubes to measure the components directly in the fog.

    The chance of something burning in the chamber when the water isn't there is real. I've smelled the odor when I shut down the fogger. There however is the same risk regardless of who makes the solution. The amount of decomp products made is rather small and I doubt it is a health risk unless you do it every day.

    Well I think we have come to the end of this thread.

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