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Oxalic acid sublimation

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Quick question guys and gals........
How many of you use a heat gun vaporiser system for oxalic acid sublimation?
Similar to that sold by Lega Italy.
 

Erichalfbee 

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I use a sublimox.
Is that similar?
 

Apiarisnt 

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It is worth bearing in mind that

"7.10 Other Experimental Properties [of oxalic acid]
...
SUBLIMES BEST @ 157 °C; @ HIGHER TEMP DECOMP INTO CO2, CARBON MONOXIDE, FORMIC ACID, & WATER; "
(from Hazardous Substances Data Bank (HSDB) : 1100 )


and uncontrolled exposure to formic acid is not terribly good for worker or queen bees (Underwood, R. The effects of temperature and dose of formic acid on treatment efficacy against Varroa destructor (Acari: Varroidae), a parasite of Apis mellifera (Hymenoptera: Apidae), February 2003, Experimental and Applied Acarology 29(3-4):303-1 )

One of the merits of the Sublimox is the sophisticated temperature control system that incoporates a proportional integral derivative (PID) controller. I am not sure you would get that degree of temperature control with any gas powered device
 

gmonag 

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It is worth bearing in mind that

"7.10 Other Experimental Properties [of oxalic acid]
...
SUBLIMES BEST @ 157 °C; @ HIGHER TEMP DECOMP INTO CO2, CARBON MONOXIDE, FORMIC ACID, & WATER; "
(from Hazardous Substances Data Bank (HSDB) : 1100 )


and uncontrolled exposure to formic acid is not terribly good for worker or queen bees (Underwood, R. The effects of temperature and dose of formic acid on treatment efficacy against Varroa destructor (Acari: Varroidae), a parasite of Apis mellifera (Hymenoptera: Apidae), February 2003, Experimental and Applied Acarology 29(3-4):303-1 )

One of the merits of the Sublimox is the sophisticated temperature control system that incoporates a proportional integral derivative (PID) controller. I am not sure you would get that degree of temperature control with any gas powered device
That has always been a cause of concern for me. A thermostatically controlled vapouriser such as the Sublimox is the ideal, but very expensive and requires ac power.

A cheap 12V vapourizer is effective but slow, especially considering that in order to avoid overheating and thus decomposing the OA, the vapouriser must be cooled between each application (by dunking in water). If this is not done then the OA will decompose, rather than vapourise, as described above.

A GasVap type vapouriser is cheap, fast and portable (no electrical power source required) but is even more prone to overheating the OA. To avoid this it must be cooled between applications to <157°C and the flame reduced during sublimation.

I'm pretty sure that many beeks are actually treating with Formic Acid and not Oxalic Acid as intended.
 
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Olbe 

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If you want to use a heat gun you will want one with the digital control so you have some control of the temperature.
I made a vaporising unit from a brass water meter housing , just removed the internal mechanism and used one of the little stainless steel cups you can get from a chefs supplies store , can't remember what these were called, but they hold quite a lot of oxalic acid- enough to do about 20 hives at a time.
We have screened floors on all our hives and so I fitted a bend to the outlet side and we vaporise from underneath through the screen , very quick to do 20 hives.
It does take a few minutes to get up to temperature but once there is brilliant.
 

Erichalfbee 

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I run my sublimox off a leisure battery and an inverter. All sits in a wheelbarrow but it’s easy with just six hives.
 

kerrbees 

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Have built my own oxalic acid vaporiser. Uses 12 volt battery with 2 switches in line (For safety) housed in a die cast box with a 3D printer blower and a narrow outlet to place in hive entrance. The heating element is a 12 volt cup heating element with a 22mm end cap. Holds just enough oxalic acid crystals for treating 1 hive. Found this very efficient as the blower provides just enough pressure to percolate right though th
IMG_4208.JPGe hive.IMG_4209.JPG
 

Gilberdyke John 

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It is worth bearing in mind that

"7.10 Other Experimental Properties [of oxalic acid]
...
SUBLIMES BEST @ 157 °C; @ HIGHER TEMP DECOMP INTO CO2, CARBON MONOXIDE, FORMIC ACID, & WATER; "
(from Hazardous Substances Data Bank (HSDB) : 1100 )


and uncontrolled exposure to formic acid is not terribly good for worker or queen bees (Underwood, R. The effects of temperature and dose of formic acid on treatment efficacy against Varroa destructor (Acari: Varroidae), a parasite of Apis mellifera (Hymenoptera: Apidae), February 2003, Experimental and Applied Acarology 29(3-4):303-1 )

One of the merits of the Sublimox is the sophisticated temperature control system that incoporates a proportional integral derivative (PID) controller. I am not sure you would get that degree of temperature control with any gas powered device
PID is more than likely complete overkill for controlling temperature in such a simple application. It reads nicely for marketing purposes. A bit like quoting db figures when selling audio electronics. "Its gotta be good cos it's got db's in its sales literature "
 

jolson 

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I've read beekeeper's concerns about formic acid, but:
  • how do you get the oxalic acid to a higher decomposition temperature once it's sublimated, without holding it in a sealed container and applying more heat? Once the OA is sublimating, its a gas expanding away from the heat source, and more likely to cool than absorb more energy.
  • I recall from old books that formic acid is/was used for treating bees. A quick google brings up dozens of sites like Formic Acid Treatment for Honey Bees - BeeKeepClub , some specifically mention formic acid vapourizers. Is the concern about the formic acid, or the carbon monoxide?
John
 

gmonag 

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I've read beekeeper's concerns about formic acid, but:
  • how do you get the oxalic acid to a higher decomposition temperature once it's sublimated, without holding it in a sealed container and applying more heat? Once the OA is sublimating, its a gas expanding away from the heat source, and more likely to cool than absorb more energy...
If the heat source is left ON whilst recharging the vapouriser the temperature, which could well have been held at 157C whilst sublimating, will rise quickly. When the OA is then placed in the cup it may decompose.
That is why it is important to cool the vapouriser to <150C between applications
 

jeff33 

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I have been using the 12v vaporiser without cooling in between hive (I do let it cool enough so the next batch of OA doesn't evaporate as soon as it touches the tray) for years and never had trouble. Mites get killed and bees seem to be doing just fine.
 

The Poot in Somerset 

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I can only assume it’s all part of the fun that happens on the Gower Peninsular....
 

gmonag 

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I have been using the 12v vaporiser without cooling in between hive (I do let it cool enough so the next batch of OA doesn't evaporate as soon as it touches the tray) for years and never had trouble. Mites get killed and bees seem to be doing just fine.
So you do cool the tray between applications... Perfect
 

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