@ ParksMtnApiary back to your original question (OAV too hot?) I will make an honest effort to answer as best as I can come up with,. Let me add, This is sure to be disputed. Lol
ScientificBeekeeping.com
Beekeeping Through the Eyes of a Biologist
Oxalic Acid: Heat Vaporization and Other Methods: Part 2 of 2 Parts
According to Randy Oliver in this article
"How does oxalic vaporization work? In the CRC Handbook of Chemistry and Physics we find that upon heating oxalic acid, the water of hydration boils off first, then at 315?F (157.222 ?C) the oxalic acid starts to sublime (go directly from solid to vapor), and finally at 372?F (188.889 ?C) any oxalic acid which has not yet sublimed decomposes to formic acid and carbon dioxide. The hot vapor rises within the confines of the hive bodies, and recondenses into tiny crystals that coat everything inside the hive. One of the problems with some vaporizers is that they get too hot too quickly and decompose, rather than evaporate the acid.
"
Can Randy be relied on as a competent source of information when it comes to bee research? I dare say yes. Even HP has directed me toward Randys work for information. The man (Randy) has dedicated , I can only dare guess, most of his life to bee research. He has researched the problem of dealing with mites extensively. There are others who make the same claims as Randy almost word for word as quoting from the CRC Handbook of Chemistry and Physics. Can this book be relied of for chemist for a quick reference to sure answers? Is this hand book and Randys reference accurate? I would certainly hope so. Have I misunderstood Randys above statement? Very possibly but seems pretty clear to me.
Why is Randys findings so important pertaining to OAV, or should be very important to we beekeepers? I will say because there are too many beekeepers losing hives to mites. Not just because of possible (too hot) set vaporizers but the treatment schedule in which OAV is applied I am thinking.
We are blessed with some very smart and brilliant minded members here at beemaster, Yet even these well educated folks are not Immuned from the destruction of the mite labeled as VARROA DESTRUCTOR. Mites are a silent-deadly, problem killer of our bees and should not be taken lightly or taken for granted by anyone, including myself.
If we go back to Beeboy01s topic that he posted here a year or so ago, (where he conducted an intensive experiment), we will find that he had a severe mite problem hive. We will find even when he used OAV administered properly, (cycle wise, schedule wise), he still had a severe mite problem with this hive for quite some time and a rough battle before finally getting things under control. Another beekeeper, now becoming famous on YouTube here in America, experienced similar results as our Beeboy01 by experimentation and sharing a short video series on his one particular hive . Could it be that a small reason or perhaps even a large reason was because their vaporizer was set to hot rendering a percentage of decomposed OAV to no effect? Again according to Randy Oliver, that can happen.. The Beeboy01 experiment was a real eye opener for me!!!
For what I am saying, and about to say is sure to be rejected even further by some of my friends, fellow beekeepers, and members here but that is ok. One can accept or reject these thoughts stemming from Randys facts as they see fit. I am simply sharing my thoughts and theories in an attempt to help. My mistake on this topic was asking about the degree of effective formic when reached as OAV is decomposed at 372f to formic and carbon dioxide and suggestion this fromic to continue to aid our bees. Unfortunately my thoughts on these decomposed components took away from what was the important question by you Parks leaving the original question that you ask lost in the shuffle. I apologize to you Parks for that.
Now Parks back to your original post and question.
I quote;
"I am looking into Johno easy vap for OAV treatments. Currently using OA dribble method and wanting to speed up the process. Alternate with MAQS. My question is a lot of the vaporizers are getting up to 400-450 degrees F. I?ve read after about 375 degrees OA turns into formic acid and carbon monoxide. Does this hurt the effectiveness of treatment or health of bees? MAQS is formic acid. Anyway, I?ve seen some beeks say this is bad. I think the easy vap and the pro vap all get into the 400-450 deg range. Any help appreciated
"
Your answer Parks according Randy Olivers paper and his information he provided from the CRC Handbook of Chemistry and Physics. Say Yes OAV can get to hot,. again quoting Randy "problems with some vaporizers is that they get too hot too quickly and decompose, rather than evaporate" The good news for your JphnO vaporizer is No, according to JohnOs answer to you in your reply 10. Because that particular brand drops quickly below the threshold to proper sublimation. Leaving Any and all remaining OAV in the proper description of Randy and his chemical book source.
Your reply 10 quoting JohnO
"The temperature controller is set at 440 F and when the OA hits the bottom of the bowl the temperature dips to about 290 F"
That 290f Parks is 143.333? Celsius and well below the decomposition temperature. So remaining OAV is well within the range of sublimation and decomposition.
But what about the other vaporizers which may also be equipped with a very high initial heat source which may also employ a sealed top, and an added aluminum heat retainer in the Bottom of the cooking pot? Does the temperature drop as quickly as yours? Some of these types have an added metal heat retainer in the bottom just for this purpose of holding the temp as steady as possible and close to the PID set temperature as possible. To retain the set temperature of 230C as long as possible. Let?s remember what Randy said At 315?F (157.222 ?C) the oxalic acid starts to sublime (go directly from solid to vapor), and finally at 372?F (188.889 ?C) ANY remaining OAV WILL decompose! Now let me add , any decomposed OAV will not benefit our bees. The question now is for a mathematician. What percentage of OAV is lost to decomposition? This lost percentage will vary from applicator to applicator depending on where the PID is set. I was hoping my theory of formic decomposing would benefit our bees. One of our experts here says not enough formic is developed in this fashion to help. So I suppose whatever is lost is equal to junk mail lol ? Can vaporizers which start off with a very high heat and equipped with heat retainer bottom still be effective? Sure they can and are if the PID is set correctly. Actually I personally prefer this type, maybe as much as the JohnO, a little more expensive but good stuff! To see if a percentage is lost, and if so, what percentage, I recommend checking your heat banded, sealed top vaporizers through a few experimental cycles and take note of the temperature drop when oxalic is being processed in conjunction with the time cycle and temp between 315?F (157.222 ?C) and 372?F (188.889 ?C) opposed to when cycle ends. as described by Randy Oliver and the CRC Handbook of Chemistry and Physics and do the math. All a person has to do is set the PID accordingly. If necessary. Simple, easy, and should eliminate the (questionable) problem of QAV and (too hot). I hope that helps you Parks and possibly others.
Phillip