Dennis!!! This is such an excellent explanation and demonstration! Felt like I was back in school and you are fantastic at presenting this topic. Thumbs UP and I'm subbing so I can come back and see what else you've been up to. Great to see such a comprehensive science-based presentation. Thank you, a coffee break very well spent. I learned something..
I know this is old, but if you would answer a question.... If I understand you right, I want to set the temperature of my vaporizer to be between the temperatures of 215 and 373 degrees, correct? thanks... glad to see your video!
You need to remember that the boiling point of water at sea level and the point at which water begins to evaporate are two very different things. Evaporation will be dependent on many factors such as ambient air temperature, the temperature of the water itself as compared to ambient air temperature (gradient) the atmospheric pressure and relative humidity levels. Therefore, it should be a consistant finding to see water completely leave the sample, forming anhydrous OA at temperatures well below the "boiling point". Also using a dish made of tin, with relatively small areas of its surface actually exposed to the heat source is of course going to cause inconsistant sublimation of the sample. The "fluffy" substance you are seeing is submlimated anhydrous OA which has recondensed on the portion of the sample above it, caused by the previously mentioned inconsistant heating of the sample. Great video though, very informative!
My kettle is always seen to have water vapour coming out of the spout and I always know that if I see that water vapour it is at 212 F or 100C, and perfect for mashing the tea. It hardly makes a jot of difference whether I'm in my caravan in Wales at sea level or in Nottingham 100 feet above the sea. How many bee keepers have checked when the Oxalic acid becomes fumes as Dennis? That would be an interesting bit of info. I doubt it is many at all. As soon as my wife sees me with my laser thermometer she tells me I'm being too exacting. But am I?
Thank you for the experimentation with oxalic acid. I am a bee keeper and a visual learner needing to know what is happening as to give effective mite treatment to the bees. It looks like the heating up process is important for sublimation and to have the equipment cool before treating the next hive.
RBH- Great vid, and to let you know I have built this type of unit using a glow plug and complete vaporization for four grams for me is about 70 seconds. Part of the time for your unit to vaporize was the air space under the foil. Thanks for all the tech. data, great job.
So, what does all of this actually mean for beekeepers applying OA to their hives? I must have missed something. I love information for it's own sake but, what practical benefit is derived from these experiments?
Biggest thing I wanted to convey is that OA vaporizes slowly and if heated too much will quickly decompose. I don't know if it's still the case but I believe most "vaporizers" got too hot and actually decomposed the OA instead of vaporizing it
@@WhatDennisDoes Thank you! That does make sense. I apologize but, I'm one of those type of guys that doesn't pick up on hints or read between the lines! hehe In other words, if the OA gets too hot, you're wasting your time doing the treatment in the first place because the OA will be rendered ineffective! I am glad that you posted the video. Thanks again! By the way, how many years have you been doing OA treatments? I'm still new to beekeeping and I have lots of questions.
@@iowasenator I've only done OA treatments a few times, with the vaporizer I built myself. It worked really well though. Had big mite kills with not too many bees dying. Unfortunately I don't have bees anymore. Family and life kind of got in the way.
@@WhatDennisDoes Oh, that's a shame. I hope that you're able to get your girls back this year. Personally, I only get bees by trapping local swarms. They bring so much joy. Do you still have all of your beekeeping equipment? (I hope so) If you need any help or advice on getting back into it, I'd love to help. I keep bees cheaply...because the hobby can be quite expensive!
So is the oxalic acid added to the extreme heat actually in the decomposition phase or is it actually just very fast evaporation/sublimation all at once? I ask this because I've read that oxalic acid can only be put on decomposition in a lab setting and in normal settings it will always sublimate before decomposition can take place. So much contradictory info with oxalic acid, it makes more sense that there is so much contradictory info about Covid-19!!!!
So Dennis do you think the more commercial grade sublimators like the 110 Pro Vap that are pre heated to 230 C* before the OA is dropped into the bowl causes the OA to decompose. Is the right way to sublimate OA to heat it more gradually?
In my opinion? Yes it should be heated gradually and carefully because what I saw is that it takes quite a while to sublime, and I don't think it's possible to rapidly turn it into vapor without it decomposing. This was just one experiment though. I would love to see an analysis done on the vapor that comes out of various commercial OA vaporizers. The thing is, even decomposed it might still be effective against mites because it turns into formic acid, so that might explain all the anecdotal evidence of even terrible vaporizers killing mites. Edit: oh let me slightly change my answer - if temperature control is good then it would be ok to drop in OA all at once and heat it quickly to that temperature. But 230C is too hot. The issue is getting the OA too hot.
@@WhatDennisDoes Thanks for the reply. The Pro Vap 110 is set to 230 C* , then you put OA into cap with the unit inverted, flip the unit over and the whole dose of OA is dropped into the preheated bowl which causes the very quick conversion to vapor (gas) and i guess formic. If the idea is to spread OA vaporized and then resolidified OA crystals through the hive the high preset temperature would be counter productive to this? I too would like to see the testing verifying the deposistion of OA after this process.
When OA reaches 215 degrees (f) the water boils off leaving anhydrous (water free) OA crystals. At 315 degrees the OA crystals start to sublime (go from a solid to a gas). At 372 degrees, OA which has not sublimed decomposes to form formic acid and carbon monoxide. However, the decomposition of OA to formic and carbon monoxide can only occur under laboratory conditions, not in the apiary.
We were advised not to use that kind of OA because there is a possibility of other ingredients in it that may not be healthy for the bees. I'm wondering if the reason some of this did not vaporize is because it contains an unidentified substance..... An interesting test would be to test this against one that is "unadulterated" OA
Dear Dennis thank you so much for the reply. I have always had quite a bit of faith in the limit stat. as it usually breaks at the designated temp for the protection of overheat in Boilers. I treated myself to an expensive laser thermometer a long time ago to save me climbing ladders to check overhead pipework temp was in the factory setting. I cannot believe how cheap the PID thermostats are these days. Yonks ago I said to my electrical pal god these stats are expensive.(on commercial ovens) he replied the closer the temp regulation the more expensive they get. I hope the Chinees who make the one I've ordered are happy with what they'll get for these excellent devices? No doubt you get a great deal of satisfaction in doing what you do in respect you have done all you can to do what is as correct as anything can possibly bee. Thanks wholeheartedly. You have given me a great deal of comfort.
I use a 12 volt vapouriser (no temperature control) with 3.5 g of OA, which pretty much fills the pan. The recommended dose is 2.5g but the vapour has to pass through the open mesh floor with my hive setup and I suspect I lose some of the OA condensing on the wire mesh. The problem I have found is, as the pan heats up, it boils over and I lose some of the active ingredient. Based on what I've seen on your excellent video, I suspect that the boiling is actually caused by the loss of the 2 water molecules (and possibly some moisture absorbed by incorrectly stored OA crystals) at around 100°C+. Any thoughts on that?
Dennis! Very good explanation. Very good comments by others as well. I would love for a chemical scientist to weigh in as well. I'd love to see an exploration of the use of foggers as well. I have seen credible comments from the Scientific bee keeper that the alcohol and or temperature breaks down the OA but he didn't go into detail.
The very best thermal chemists are need not that Dennis is lacking at all. It's always nice to have fellow researchers agree and confirm and the yes you are right is nice and all that's required. The feel good factor ? I suppose. One thing Dennis has proven is that the questing soul is necessary many a time. After all, the thinking 'beekeeper' has a deep desire to help his bees survive and bee happy. Varroa certainly need the strictest attention in the hope that they will be exterminated completely in the future.
Thank you for sharing this video. Could I ask you a question? As you were saying in the video, oxalic acid sublimes between 157 and 189.5 degrees Centigrade. Above this temperature, it turns into formic acid and Carbon dioxide. Now here is my question: would it be possible to treat against varroa using oxalic acid subliming devices such as Varrox? Bearing in mind that such devices are not equipped with thermostats and so wouldn't necessarily be able to keep the temperature between 157 and 189.5 degrees. In fact, the temperature of the aluminum plate may well reach 250, even 300 degrees Centigrade or more. As far as I know, the only oxalic acid subliming devices that are able to control temperature are those that can either use a power generator or that can be plugged into the mains, with a voltage of 110/200 V. So there's clearly something that I'm missing here. Could you help me get it right? Thank you. Best, Valentin
You're not missing anything, even the most popular commercial devices cannot precisely control the temperature, so there is the possibility that the OA decomposes. The Varrox instructions even say the device can get up to 300C. I have seen videos of the Varrox working, and it can sublimate without destroying OA. This is probably because it heats up so slowly, so by the time it exceeds 189.5C, all the OA has already sublimated away. Their instructions say to only heat for 2.5 minutes, and between uses it should be cooled in a bucket of water "so that with the next use, no vaporisation begins before the appliance is inserted into the hive". Obviously this is time consuming, so a beekeeper with many hives to treat might try to take shortcuts and leave the vaporizer hot between treatments. This is where they could get in trouble.
Awesome. Well done! From one science/engineer guy to another, thank you for this👍. I am missing only two last pieces of information. What is the heat of vaporization? 1, How much energy does it take to vaporize 10 grams(J), say starting at ambient of 65 degF. ? 2, how fast can it be driven (J/s) without decomposing it? (recognizing it is fundamentally temperature dependant) Need some input to those two data points to establish if I need to make a 10 watt or 1000 watt vaporizer?
I don't believe the formation of formic acid would be terribly harmful; Ants make formic acid to sting with, and we use it to preserve some foods in low concentrations. Though still an effective treatment, formation of formic acid is undesirable since it would do less to a mite than oxalic acid does.
Thanks for this great video! Maybe you like to know that actually there is a new oxalic acid vaporizer with temperature control named OXALIKA. You can find a video named "Oxalic Acid Vaporizer OXALIKA - introduction video".
Thanks Dennis for exacting the temperature at which oxalic acid dihydrate turns into a gas (but is it a gas and am I incorrect in that designation?) There is an awful lot of differing temperatures stated on You Tube by many well meaning beekeepers who ar eno doubt getting the info from the makers of the tools they are using? I saw that Oxalic acid sublimates at 157 c (turns into a gas) somewhere on a scientific site on the net. Not wanting my self made sublimator contraption getting too hot thereby having it develop dangerous fumes I opted for a limit stat that opened circuit at 160 C. These bi-metalic stats as you will know are about $7 or so. I noticed that there was a covering of white powder inside the copper tube after the episode of treatment. I wondered why there were no clouds of oxalic acid vapour seen with the demos in the USA! I notice an experience UK beekeeper 'never the less', sets his machine at 230C probably as per the 'Zappers' instructions ---- I think he said it was factory set? At such elevated temperatures well above the so called danger temp of 315F whereby noxious fumes occur It poses the question are the bees getting more formic acid than oxalic acid fumes? Sorry I've mixed up the C and F temps. As an ex commercial heating eng I should really know how to add 9 or is it subtract 9 add 5 or better still look at most thermometers where one can choose either imperial or mediterranean!
Thank you, I hoped to enlighten with this video and settle once and for all the temperature of what OA vaporizers should operate at. I do think many bee keepers are inadvertantly dosing their hives with OA byproducts like formic acid at such high temps. The bimetallic thermostats as you know tend to cycle so it could be alternating between less than and greater than the sublimation temperature. A residue is a good sign though because of course the result of fogging a hive with OA vapor is a fine deposit of OA crystals as it condenses.
Exiting Video indeed! It seems as you proofed that you dried oxalic acid dihydrate that way and were still able to sublimate the "dry" oxalic acid - wel, as you said you were assuming . So why we all are not using just oxalic acid in the first place ? By some . Will it react the same way ? I guess no .
It's hard to find because OA slowly turns into oxalic acid dihydrate as it pulls water from the air. So it needs to be dried then stored in an air tight container.
I thought even at higher temperature ox acid vaporize before it decomposes(vapor escape before it is heated enough, some part decomposes probably)..I think for decomposing ox it need to be heated in closed chamber so ox vapor cannot escape and be further heated to decomposing.. But i have no scientific tests to back this..Best would be to capture vapours at different temp. and analyze it in lab(but that is beyond me and most ppl.)
If you look at the OA when it is vaporizing, you'll see a white vapor coming off - these are actually tiny crystals of OA that are forming as it cools in air and turns back to a solid. When I heat it to a much higher temperature and it rapidly turns to liquid and disappears, there should be a ton of white vapor in the air if it was vaporizing. There isn't because it is decomposing. I have an organic chemistry glassware set - I could maybe try to recollect and condense the vapor. I'm pretty sure I would end up with a liquid (formic acid) or nothing at all, if the decomp. products are mostly CO2 and CO.
That is very informative and what I suspected because it seemed much less fumes than all the demos in the US when I did my experiment. My bees must have just got oxalic acid at 60C? All I can confirm it killed 60 mites whereas before the treatment I never saw one mite even with icing sugar dusting to all the bees. Just goes to show....... never have a closed mind!
Matter undergoing phase changes involve latent heat. As an example, it is impossible under normal circumstances to heat water past its boiling point. The harder you try, the faster it boils off. However, if you pressurize the vessel, heat it, then release the pressure, you will note a very sudden temperature drop. It will either drop to the boiling point with some of the water having vaporized, or all of the water will convert to a gas that is between your original temperature and the boiling point. I suspect this is in play with oxalic acid. It probably doesn't decomp much except under specific lab settings. So even though it's turned liquid and vanishing at really high temps, it might actually still be sublimating, latent heat coming into play, and keeping the OA from decomping.
Maybe a way to test this would be to heat the OA to a liquid then rapidly cool it before it vaporizes. If it goes back to a solid then maybe it's still OA, but I suspect it would stay liquid. I haven't found one yet, but I don't think the phase diagram for OA has a liquid phase at ATM.
If you place it in a pressurized vessel, you should be able to hit the decom temp without vaporization. I am curious if decomp is affected by pressure. One thing you could do is call an industrial lab and ask them about OA's properties.
Great video unfortunately the masses of the people just didn’t get what you said probably only 2 to 5% people understood what you just explained. We need more intelligent people like yourself to explain the technical aspect of things Thanks again and I did learn something 💯✨👍
Sublimation means that you directly shifts from solid to gas. You use the example of water in your video. Sublimation of water happens when you sublimate the water from (ice=solid) to gas. This is generally done under vacuum at freezing temperature (freeze dry). You also mentioned water and its evaporation. Evaporation is when when changes state from liquid to gas between 0-100ºC whilst vaporization is when it becomes gas after 100ºC (when it passes the boiling point). My understanding of sublimation of oxalic acid is that it has to change state from solid to gas without getting liquid. I am no chemist so my interpretation can be wrong. This said great video. Oh and you did not dry the oxalic acid (in a drying oven) before you weighed it, so it had moisture in it (beside the H20 in the molecule). I set my homemade bandheater vaporizer at 230ºC like the provap and it works well treating hives for Varroa destructor. Finally, did you check that your aluminum foil is actually the right temperature? For my vaporizer, I had to set my PID by -20C to get exactly 230ºC in the bottom of the pot.
Dennis, I'm just an ignorant old country boy, so forgive me for my meddling into your video... But wouldn't it be more scientific (not to mention easier), if you make an aluminum tray that is the 'exact' shape of your heater (giving best heat transfer) and tare the weight of the tray, giving you the exact weight before and during tests? The tray could be made simply from an aluminum soda can (cleaned of paint) and even given a little 'handle'. I believe the 'wrinkles' in your aluminum foil is preventing the registered heat from contacting the Oxalic acid, giving you false readings.
+RonRay that's what these comments are for! You're welcome to meddle. And yours is definitely a valid concern. In fact the heat within the aluminum block itself might be different between the temperature probe and heater element. The probe itself isn't extremely accurate either. If I re-do this experiment I will try to do it with real lab equipment. In the meantime I hope these results are helpful in the absence of more scientific data and videos out there.
You do have a major issue of heat transfer to the aluminum foil. You are relying mostly on radiate heat from your heating block. The sublimation of the oxalic acid will rapidly cool off the aluminum foil, reducing the temperature below the sublimation temperature. If you preform the aluminum foil to sit flat on the heating block bottom AND spread the oxalic acid into a thin layer (rather than clumps), you will get better experimental results. Not perfect heat transfer, but better.
With all this hard work and research that you have done, maybe it's not the ox that is killing the mites after all, perhaps it's the Formic Acid and co2? Especially since keepers heat it up until all is disipated and 99.9 percent mites are destroyed? I really would like your response. PS Thank you for your hard work!!
+phillip hall I do suspect this is happening, but if the instructions on commercial vaporizers are followed carefully, I think the majority of the OA sublimates and doesn't break down. It just takes longer than many expect.
Since the dribble method works with no heat at all I believe it is the oa that kills the mites. Although Formic acid is an effective treatment for mites as well.
I can save you guys a lot of trouble. As someone with at least as much experience as Randy Oliver, I can make the absolute claim that vaporizing Oxalic Acid into beehives is a waste of time and dangerous to human health. The process is attractive to beekeepers because it appears an easy option. It doesn't work. The only way to use Oxalic Acid successfully in a Beehive is to dissolve it in Glycerine and use it in a way that can see it applied between the frames in the brood. Any other method is delusional There will likely be a lot of people who disagree, but then there are those who believe the world is flat
What does the chemicals do, specifically, to the mites? Work on their nervous system? Chase them out? Suffocate them? What does it do to the bees? {"EW smells bad, but we can handle it", "Ooh, smells nice" or Nothing.} Do drones fan the entrance as they do when you use the Smoker?
The OA vapour does not harm the bees because they have a hard exoskeleton but the mites have soft sticky feet and mouthparts. My understanding is that the small condensed OA crystals that come in contact with the mites in the hive, either from the bees or from hive parts, burn the footpads or mouthparts and either poison/dessicate the mite or cause it to let go of its host - either way, it falls out of the hive through the mesh floor.
Ok great video! Some beekeepers are melting oxalic acid into a liquid with Ethel alcohol then fogging thru a propane insect fogger. With what you have here is the heat sending the oa out in decomposed form or does the Ethel alcohol change it to actually allow it to fog and work the way it should? Check out justbeecuz channel. Thanks!
Interesting! I haven't heard of this method before. OA looks to be very soluble in ethanol (237 g/L @ 15 °C). As long as it doesn't get too hot I would guess the OA doesn't decompose. But then I would assume the ethanol would evaporate away much faster than the OA leaving solid OA behind. Certainly worth some experimentation - maybe in a future video!
If it does work properly being used in an insect fogger , the treatments of beehives would only require mere seconds of time per hive rather than 5-10 mins , it would also seem to be far less invasive for the bees themselves and the equipment itself would be available at nearly any hardware store at a very affordable price .....any testing or reliable reports of this use would truly be appreciated...Thanks
If you want to make money in Beekiping don't try to invent stuff like that.Time is money.Just watch Fat bee Man, how he does with is nice $40 vaporizer with propane.15 sec per hive and he was doing this for many many years.We use it, here ,in Az on our 2000 hives ,full size ,and 500 nucs.
Think this is being over thought here and process over looked. Heat vapourisor up first to desired temperature 180c/350f, put oxalic acid in vapourisor and cap depending on vapourisor. Then watch mites die lol, end of story. Simple
Dennis!!! This is such an excellent explanation and demonstration! Felt like I was back in school and you are fantastic at presenting this topic. Thumbs UP and I'm subbing so I can come back and see what else you've been up to. Great to see such a comprehensive science-based presentation. Thank you, a coffee break very well spent. I learned something..
the carrots in the hive at the end got me - lol - great video!
I know this is old, but if you would answer a question.... If I understand you right, I want to set the temperature of my vaporizer to be between the temperatures of 215 and 373 degrees, correct? thanks... glad to see your video!
You need to remember that the boiling point of water at sea level and the point at which water begins to evaporate are two very different things. Evaporation will be dependent on many factors such as ambient air temperature, the temperature of the water itself as compared to ambient air temperature (gradient) the atmospheric pressure and relative humidity levels. Therefore, it should be a consistant finding to see water completely leave the sample, forming anhydrous OA at temperatures well below the "boiling point". Also using a dish made of tin, with relatively small areas of its surface actually exposed to the heat source is of course going to cause inconsistant sublimation of the sample. The "fluffy" substance you are seeing is submlimated anhydrous OA which has recondensed on the portion of the sample above it, caused by the previously mentioned inconsistant heating of the sample. Great video though, very informative!
My kettle is always seen to have water vapour coming out of the spout and I always know that if I see that water vapour it is at 212 F or 100C, and perfect for mashing the tea. It hardly makes a jot of difference whether I'm in my caravan in Wales at sea level or in Nottingham 100 feet above the sea.
How many bee keepers have checked when the Oxalic acid becomes fumes as Dennis? That would be an interesting bit of info. I doubt it is many at all.
As soon as my wife sees me with my laser thermometer she tells me I'm being too exacting. But am I?
Thank you for the experimentation with oxalic acid. I am a bee keeper and a visual learner needing to know what is happening as to give effective mite treatment to the bees. It looks like the heating up process is important for sublimation and to have the equipment cool before treating the next hive.
Yes, I think that's the way to go too. Glad you liked the video!
RBH-
Great vid, and to let you know I have built this type of unit using a glow plug and complete vaporization for four grams for me is about 70 seconds. Part of the time for your unit to vaporize was the air space under the foil. Thanks for all the tech. data, great job.
Thank you for sharing this video. I cleared what is the point with OO sublimation.
So, what does all of this actually mean for beekeepers applying OA to their hives? I must have missed something. I love information for it's own sake but, what practical benefit is derived from these experiments?
Biggest thing I wanted to convey is that OA vaporizes slowly and if heated too much will quickly decompose. I don't know if it's still the case but I believe most "vaporizers" got too hot and actually decomposed the OA instead of vaporizing it
@@WhatDennisDoes Thank you! That does make sense. I apologize but, I'm one of those type of guys that doesn't pick up on hints or read between the lines! hehe In other words, if the OA gets too hot, you're wasting your time doing the treatment in the first place because the OA will be rendered ineffective! I am glad that you posted the video. Thanks again! By the way, how many years have you been doing OA treatments? I'm still new to beekeeping and I have lots of questions.
@@iowasenator I've only done OA treatments a few times, with the vaporizer I built myself. It worked really well though. Had big mite kills with not too many bees dying. Unfortunately I don't have bees anymore. Family and life kind of got in the way.
@@WhatDennisDoes Oh, that's a shame. I hope that you're able to get your girls back this year. Personally, I only get bees by trapping local swarms. They bring so much joy. Do you still have all of your beekeeping equipment? (I hope so) If you need any help or advice on getting back into it, I'd love to help. I keep bees cheaply...because the hobby can be quite expensive!
Oxalic acid sublimation manuals for beekeeping recommend minimum 4degreeC as atmospheric condition. Is that to prevent oxalic acid recrystallisation?
So is the oxalic acid added to the extreme heat actually in the decomposition phase or is it actually just very fast evaporation/sublimation all at once? I ask this because I've read that oxalic acid can only be put on decomposition in a lab setting and in normal settings it will always sublimate before decomposition can take place.
So much contradictory info with oxalic acid, it makes more sense that there is so much contradictory info about Covid-19!!!!
Very interesting. I have a thermostatic control on my vaporizer so that it does not get too hot!
So Dennis do you think the more commercial grade sublimators like the 110 Pro Vap that are pre heated to 230 C* before the OA is dropped into the bowl causes the OA to decompose. Is the right way to sublimate OA to heat it more gradually?
In my opinion? Yes it should be heated gradually and carefully because what I saw is that it takes quite a while to sublime, and I don't think it's possible to rapidly turn it into vapor without it decomposing. This was just one experiment though. I would love to see an analysis done on the vapor that comes out of various commercial OA vaporizers. The thing is, even decomposed it might still be effective against mites because it turns into formic acid, so that might explain all the anecdotal evidence of even terrible vaporizers killing mites.
Edit: oh let me slightly change my answer - if temperature control is good then it would be ok to drop in OA all at once and heat it quickly to that temperature. But 230C is too hot. The issue is getting the OA too hot.
@@WhatDennisDoes Thanks for the reply. The Pro Vap 110 is set to 230 C* , then you put OA into cap with the unit inverted, flip the unit over and the whole dose of OA is dropped into the preheated bowl which causes the very quick conversion to vapor (gas) and i guess formic. If the idea is to spread OA vaporized and then resolidified OA crystals through the hive the high preset temperature would be counter productive to this? I too would like to see the testing verifying the deposistion of OA after this process.
@@WhatDennisDoes I will have to experiment with Much lower temp set on the controller, Thanks for the video it was very informative.
When OA reaches 215 degrees (f) the water boils off leaving anhydrous (water free) OA crystals. At 315 degrees the OA crystals start to sublime (go from a solid to a gas). At 372 degrees, OA which has not sublimed decomposes to form formic acid and carbon monoxide. However, the decomposition of OA to formic and carbon monoxide can only occur under laboratory conditions, not in the apiary.
We were advised not to use that kind of OA because there is a possibility of other ingredients in it that may not be healthy for the bees. I'm wondering if the reason some of this did not vaporize is because it contains an unidentified substance..... An interesting test would be to test this against one that is "unadulterated" OA
So what do i need to set the temperature of my easy-vap to. You may have figured something out, but you certainly didn’t convey it very well.
Dear Dennis thank you so much for the reply. I have always had quite a bit of faith in the limit stat. as it usually breaks at the designated temp for the protection of overheat in Boilers. I treated myself to an expensive laser thermometer a long time ago to save me climbing ladders to check overhead pipework temp was in the factory setting.
I cannot believe how cheap the PID thermostats are these days.
Yonks ago I said to my electrical pal god these stats are expensive.(on commercial ovens) he replied the closer the temp regulation the more expensive they get. I hope the Chinees who make the one I've ordered are happy with what they'll get for these excellent devices?
No doubt you get a great deal of satisfaction in doing what you do in respect you have done all you can to do what is
as correct as anything can possibly bee. Thanks wholeheartedly. You have given me a great deal of comfort.
I use a 12 volt vapouriser (no temperature control) with 3.5 g of OA, which pretty much fills the pan. The recommended dose is 2.5g but the vapour has to pass through the open mesh floor with my hive setup and I suspect I lose some of the OA condensing on the wire mesh.
The problem I have found is, as the pan heats up, it boils over and I lose some of the active ingredient. Based on what I've seen on your excellent video, I suspect that the boiling is actually caused by the loss of the 2 water molecules (and possibly some moisture absorbed by incorrectly stored OA crystals) at around 100°C+. Any thoughts on that?
Sounds like that's the case. Would you be able to cycle the heater so it doesn't get too hot too fast?
Dennis! Very good explanation. Very good comments by others as well. I would love for a chemical scientist to weigh in as well. I'd love to see an exploration of the use of foggers as well. I have seen credible comments from the Scientific bee keeper that the alcohol and or temperature breaks down the OA but he didn't go into detail.
The very best thermal chemists are need not that Dennis is lacking at all. It's always nice to have fellow researchers agree and confirm and the yes you are right is nice and all that's required. The feel good factor ? I suppose. One thing Dennis has proven is that the questing soul is necessary many a time.
After all, the thinking 'beekeeper' has a deep desire to help his bees survive and bee happy.
Varroa certainly need the strictest attention in the hope that they will be exterminated completely in the future.
Very well explained sir👍👍
Thank you for sharing this video. Could I ask you a question?
As you were saying in the video, oxalic acid sublimes between 157 and 189.5 degrees Centigrade. Above this temperature, it turns into formic acid and Carbon dioxide. Now here is my question: would it be possible to treat against varroa using oxalic acid subliming devices such as Varrox? Bearing in mind that such devices are not equipped with thermostats and so wouldn't necessarily be able to keep the temperature between 157 and 189.5 degrees. In fact, the temperature of the aluminum plate may well reach 250, even 300 degrees Centigrade or more.
As far as I know, the only oxalic acid subliming devices that are able to control temperature are those that can either use a power generator or that can be plugged into the mains, with a voltage of 110/200 V.
So there's clearly something that I'm missing here. Could you help me get it right?
Thank you.
Best,
Valentin
You're not missing anything, even the most popular commercial devices cannot precisely control the temperature, so there is the possibility that the OA decomposes. The Varrox instructions even say the device can get up to 300C. I have seen videos of the Varrox working, and it can sublimate without destroying OA. This is probably because it heats up so slowly, so by the time it exceeds 189.5C, all the OA has already sublimated away. Their instructions say to only heat for 2.5 minutes, and between uses it should be cooled in a bucket of water "so that with the next use, no vaporisation begins before the appliance is inserted into the hive". Obviously this is time consuming, so a beekeeper with many hives to treat might try to take shortcuts and leave the vaporizer hot between treatments. This is where they could get in trouble.
Awesome. Well done! From one science/engineer guy to another, thank you for this👍. I am missing only two last pieces of information. What is the heat of vaporization? 1, How much energy does it take to vaporize 10 grams(J), say starting at ambient of 65 degF. ? 2, how fast can it be driven (J/s) without decomposing it? (recognizing it is fundamentally temperature dependant) Need some input to those two data points to establish if I need to make a 10 watt or 1000 watt vaporizer?
I don't believe the formation of formic acid would be terribly harmful; Ants make formic acid to sting with, and we use it to preserve some foods in low concentrations. Though still an effective treatment, formation of formic acid is undesirable since it would do less to a mite than oxalic acid does.
Excellent presentation, thanks.
Thanks for this great video!
Maybe you like to know that actually there is a new oxalic acid vaporizer with temperature control named OXALIKA. You can find a video named "Oxalic Acid Vaporizer OXALIKA - introduction video".
Thanks Dennis for exacting the temperature at which oxalic acid dihydrate turns into a gas (but is it a gas and am I incorrect in that designation?) There is an awful lot of differing temperatures stated on You Tube by many well meaning beekeepers who ar eno doubt getting the info from the makers of the tools they are using?
I saw that Oxalic acid sublimates at 157 c (turns into a gas) somewhere on a scientific site on the net. Not wanting my self made sublimator contraption getting too hot thereby having it develop dangerous fumes I opted for a limit stat that opened circuit at 160 C. These bi-metalic stats as you will know are about $7 or so. I noticed that there was a covering of white powder inside the copper tube after the episode of treatment. I wondered why there were no clouds of oxalic acid vapour seen with the demos in the USA!
I notice an experience UK beekeeper 'never the less', sets his machine at 230C probably as per the 'Zappers' instructions ---- I think he said it was factory set? At such elevated temperatures well above the so called danger temp of 315F whereby noxious fumes occur It poses the question are the bees getting more formic acid than oxalic acid fumes? Sorry I've mixed up the C and F temps. As an ex commercial heating eng I should really know how to add 9 or is it subtract 9 add 5 or better still look at most thermometers where one can choose either imperial or mediterranean!
Thank you, I hoped to enlighten with this video and settle once and for all the temperature of what OA vaporizers should operate at. I do think many bee keepers are inadvertantly dosing their hives with OA byproducts like formic acid at such high temps. The bimetallic thermostats as you know tend to cycle so it could be alternating between less than and greater than the sublimation temperature. A residue is a good sign though because of course the result of fogging a hive with OA vapor is a fine deposit of OA crystals as it condenses.
Simply awesome. Thanks Mate. 😎
Exiting Video indeed! It seems as you proofed that you dried oxalic acid dihydrate that way and were still able to sublimate the "dry" oxalic acid - wel, as you said you were assuming . So why we all are not using just
oxalic acid in the first place ? By some . Will it react the same way ? I guess no .
It's hard to find because OA slowly turns into oxalic acid dihydrate as it pulls water from the air. So it needs to be dried then stored in an air tight container.
I thought even at higher temperature ox acid vaporize before it decomposes(vapor escape before it is heated enough, some part decomposes probably)..I think for decomposing ox it need to be heated in closed chamber so ox vapor cannot escape and be further heated to decomposing.. But i have no scientific tests to back this..Best would be to capture vapours at different temp. and analyze it in lab(but that is beyond me and most ppl.)
If you look at the OA when it is vaporizing, you'll see a white vapor coming off - these are actually tiny crystals of OA that are forming as it cools in air and turns back to a solid. When I heat it to a much higher temperature and it rapidly turns to liquid and disappears, there should be a ton of white vapor in the air if it was vaporizing. There isn't because it is decomposing. I have an organic chemistry glassware set - I could maybe try to recollect and condense the vapor. I'm pretty sure I would end up with a liquid (formic acid) or nothing at all, if the decomp. products are mostly CO2 and CO.
You want the OA to decompose, we are actually treating bees with formic acid from oxalic acid. That's why the vaporizers run around 400F
That is very informative and what I suspected because it seemed much less fumes than all the demos in the US when I did my experiment. My bees must have just got oxalic acid at 60C? All I can confirm it killed 60 mites whereas before the treatment I never saw one mite even with icing sugar dusting to all the bees. Just goes to show....... never have a closed mind!
Matter undergoing phase changes involve latent heat. As an example, it is impossible under normal circumstances to heat water past its boiling point. The harder you try, the faster it boils off. However, if you pressurize the vessel, heat it, then release the pressure, you will note a very sudden temperature drop. It will either drop to the boiling point with some of the water having vaporized, or all of the water will convert to a gas that is between your original temperature and the boiling point.
I suspect this is in play with oxalic acid. It probably doesn't decomp much except under specific lab settings. So even though it's turned liquid and vanishing at really high temps, it might actually still be sublimating, latent heat coming into play, and keeping the OA from decomping.
Maybe a way to test this would be to heat the OA to a liquid then rapidly cool it before it vaporizes. If it goes back to a solid then maybe it's still OA, but I suspect it would stay liquid. I haven't found one yet, but I don't think the phase diagram for OA has a liquid phase at ATM.
If you place it in a pressurized vessel, you should be able to hit the decom temp without vaporization. I am curious if decomp is affected by pressure.
One thing you could do is call an industrial lab and ask them about OA's properties.
Great video unfortunately the masses of the people just didn’t get what you said probably only 2 to 5% people understood what you just explained. We need more intelligent people like yourself to explain the technical aspect of things Thanks again and I did learn something 💯✨👍
Sublimation means that you directly shifts from solid to gas. You use the example of water in your video. Sublimation of water happens when you sublimate the water from (ice=solid) to gas. This is generally done under vacuum at freezing temperature (freeze dry). You also mentioned water and its evaporation. Evaporation is when when changes state from liquid to gas between 0-100ºC whilst vaporization is when it becomes gas after 100ºC (when it passes the boiling point). My understanding of sublimation of oxalic acid is that it has to change state from solid to gas without getting liquid. I am no chemist so my interpretation can be wrong. This said great video. Oh and you did not dry the oxalic acid (in a drying oven) before you weighed it, so it had moisture in it (beside the H20 in the molecule). I set my homemade bandheater vaporizer at 230ºC like the provap and it works well treating hives for Varroa destructor. Finally, did you check that your aluminum foil is actually the right temperature? For my vaporizer, I had to set my PID by -20C to get exactly 230ºC in the bottom of the pot.
Dennis, I'm just an ignorant old country boy, so forgive me for my meddling into your video... But wouldn't it be more scientific (not to mention easier), if you make an aluminum tray that is the 'exact' shape of your heater (giving best heat transfer) and tare the weight of the tray, giving you the exact weight before and during tests? The tray could be made simply from an aluminum soda can (cleaned of paint) and even given a little 'handle'.
I believe the 'wrinkles' in your aluminum foil is preventing the registered heat from contacting the Oxalic acid, giving you false readings.
+RonRay that's what these comments are for! You're welcome to meddle. And yours is definitely a valid concern. In fact the heat within the aluminum block itself might be different between the temperature probe and heater element. The probe itself isn't extremely accurate either. If I re-do this experiment I will try to do it with real lab equipment. In the meantime I hope these results are helpful in the absence of more scientific data and videos out there.
You do have a major issue of heat transfer to the aluminum foil. You are relying mostly on radiate heat from your heating block.
The sublimation of the oxalic acid will rapidly cool off the aluminum foil, reducing the temperature below the sublimation temperature.
If you preform the aluminum foil to sit flat on the heating block bottom AND spread the oxalic acid into a thin layer (rather than clumps), you will get better experimental results. Not perfect heat transfer, but better.
With all this hard work and research that you have done, maybe it's not the ox that is killing the mites after all, perhaps it's the Formic Acid and co2? Especially since keepers heat it up until all is disipated and 99.9 percent mites are destroyed? I really would like your response. PS Thank you for your hard work!!
+phillip hall I do suspect this is happening, but if the instructions on commercial vaporizers are followed carefully, I think the majority of the OA sublimates and doesn't break down. It just takes longer than many expect.
What Dennis Does Thanks Dennis, irregardless,? Isn't it great that we do have a way to fight the Mites!! Thank you sir keep up the good work !!
Since the dribble method works with no heat at all I believe it is the oa that kills the mites. Although Formic acid is an effective treatment for mites as well.
It burns their little feet off.
That's how the acid kills the mites.
Some say that the mites will develop immunity. I think not.
well done..
I can save you guys a lot of trouble.
As someone with at least as much experience as Randy Oliver, I can make the absolute claim that vaporizing Oxalic Acid into beehives is a waste of time and dangerous to human health.
The process is attractive to beekeepers because it appears an easy option.
It doesn't work.
The only way to use Oxalic Acid successfully in a Beehive is to dissolve it in Glycerine and use it in a way that can see it applied between the frames in the brood.
Any other method is delusional
There will likely be a lot of people who disagree, but then there are those who believe the world is flat
What does the chemicals do, specifically, to the mites? Work on their nervous system? Chase them out? Suffocate them? What does it do to the bees? {"EW smells bad, but we can handle it", "Ooh, smells nice" or Nothing.} Do drones fan the entrance as they do when you use the Smoker?
The OA vapour does not harm the bees because they have a hard exoskeleton but the mites have soft sticky feet and mouthparts. My understanding is that the small condensed OA crystals that come in contact with the mites in the hive, either from the bees or from hive parts, burn the footpads or mouthparts and either poison/dessicate the mite or cause it to let go of its host - either way, it falls out of the hive through the mesh floor.
NICE! Thank you VERY much, Colin!
Ok great video! Some beekeepers are melting oxalic acid into a liquid with Ethel alcohol then fogging thru a propane insect fogger. With what you have here is the heat sending the oa out in decomposed form or does the Ethel alcohol change it to actually allow it to fog and work the way it should?
Check out justbeecuz channel.
Thanks!
Interesting! I haven't heard of this method before. OA looks to be very soluble in ethanol (237 g/L @ 15 °C). As long as it doesn't get too hot I would guess the OA doesn't decompose. But then I would assume the ethanol would evaporate away much faster than the OA leaving solid OA behind. Certainly worth some experimentation - maybe in a future video!
If it does work properly being used in an insect fogger , the treatments of beehives would only require mere seconds of time per hive rather than 5-10 mins , it would also seem to be far less invasive for the bees themselves and the equipment itself would be available at nearly any hardware store at a very affordable price .....any testing or reliable reports of this use would truly be appreciated...Thanks
If you want to make money in Beekiping don't try to invent stuff like that.Time is money.Just watch Fat bee Man, how he does with is nice $40 vaporizer with propane.15 sec per hive and he was doing this for many many years.We use it, here ,in Az on our 2000 hives ,full size ,and 500 nucs.
Think this is being over thought here and process over looked. Heat vapourisor up first to desired temperature 180c/350f, put oxalic acid in vapourisor and cap depending on vapourisor. Then watch mites die lol, end of story. Simple
Same question as Randy ⬇⬇⬇
You are over thinking Beekeeping....