Is there OA left in the vaporizer? How much time does that process take? I put 2 grams in my vaporizer and in 2.5 minutes it's gone.

 

Yeah I've heard that about vaporizers that aren't temperature-controlled. Here's the claim from Hoosierville Beekeeping, where I bought mine:

This highly sophisticated delivery device distributes oxalic acid in the correct dose every time. It does not burn the oxalic acid like other vaporizers on the market. With the temperature control set to the correct temperature range, the oxalic acid will not burn and create formic acid and carbon monoxide that is potentially harmful to the bees.

One of the problems with some vaporizers using uncontrolled temperature is that they get too hot too quickly and decompose the oxalic acid rather than vaporize it. If oxalic acid is heated to 372°F (188°C) it denigrates and burns giving off potentially harmful fumes to the bees. This is why it is so important to keep the temperature between 315°F (157ᵒC) and 372°F (188°C).

I can't defend the science behind these claims, but it makes sense that you'd want to vaporize--and not burn--the OA. That said, it does take me 15-20 minutes for the process, which I know would be a long time for people with a lot of hives. I've only got a couple though, so it's no big deal for me.

And yep, there's still white substance left in the tray when I'm done. That's the reason I stir it around in the middle of the process--trying to ensure it gets used up. I'm not really worried about any leftover material though...not sure, but I suspect that could be the remnants of vaporized (but not burned) OA.

 

I call BS. The studies were done using the common vaporizers which were shown to not be harmful to the bees. Perhaps heating the oxalic acid at a lower temperature is not as effective at killing mites? In my mind the oxalic acid vaporizes and leaves the tray (it's now a gas). This ceases any additional heating. When I treat a hive I'm done with no residual in 3 minutes flat. 300 bucks is a little steep too.
Perhaps the dy no mite is a solution looking for a problem? JMHO.

 

Capitalizing on human fears! Expensive solution to a non existent problem!

 

Most commercial vaporizers are built so that the temperature rise vaporizes the OA way prior to any conversion. No need for any temperature control.

 

This would be correct. The vaporizer does not go from the ambient temperature to the vapor point instantly. It takes a minute or two to get there. So by the time it gets up to the danger point of 372 degrees, all of the OA is already vaporized. If that were not the case. it would only take 5 seconds to vaporize each hive.

 

Bee Arthur - the camera work was great - and that is a nice looking setup you got going. The temp control maybe a bit overkill for this application, but it looks super adjustable, so.... consider.....
as SNL and Dudelt pointed out (and I have found this too), the OA will flash off long before you hit 375. You could reduce your cycle time, and get a more complete burn by cranking your temp up a bit - (also, I use a dinky battery like that too - it really helps to charge it right before use). I saw the vapors coming out the top so you got some oa all around, but there looked like quiet a bit still left over that didn't vaporize.
The OA is cheap, you might consider doing a few test burns at a few higher temps - until you can get all the OA to vaporize off with just a cycle or two. my little home made vaporizer, on a battery like yours, does a complete burn in about 2 minutes - there is nothing save a little fleck or two of ash when its done....if the battery is low - it can take much longer or just never get hot enough to even to vaporize much of it.
Sky

 

Sky - Good points, I think I will try cranking up the heat next time to see if I can make the process quicker, thanks.

To be clear to everyone, I'm not affiliated with the vaporizer. I've also never recommended it to other beeks due to its price and the fact that others seemed to get along fine without the temp control. That said, it does work so I won't be tossing it out for another anytime soon.

 

Like Barhopper and others comment that treatment seems to be taking an inordinately long time and there's a lot of OA left in the heating pan. I've got a video of a Sublimox vaporiser in use (bottom of the page) which takes less than a minute from start to finish. In this type of vaporiser the oxalic acid is dropped into a preheated pan and immediately vaporises. The vapour is forced through a small tube which is narrow enough to be pushed through a 9mm hole in the hive floor. If the OA you're using is of high purity (which it will be from a reputable supplier) it should all go.

 

Impressive, thanks for the vid.

 

That guy is a lot braver than I am. I like my lungs to much to do that. To the OP that is interesting. I'll research that model more. I'm very happy with mine, thanks Larry, but always willing to see different products.

 

The demo outside the hive is using a few millilitres of water! It was to demonstrate how forcefully and quickly the OA vaporises. I should have made that clearer. When used with OA in a properly sealed hive there's almost no vapour that escapes.

 

LINK http://myhoosiervillebeekeeping.webs.com/oxalic-acid-vaporizer

 

I appreciate the camera work and the tutorial with your OA vaporizer. It seems to have left a lot of the OA in the pan after treatment as others stated. It also seems quite costly and takes a lot of time for treatment. Good thing you only have one hive! lol I have a total of 50.00 or so into mine, it works quite well and in about two minutes. Good luck with the bees. I'd like to see a vid on the mite drop soon.

 

It was 1891.
By Dr. Edward Turner.
(°F)

“Sublimed oxalic acid rises slowly,
as already mentioned,
at 212°.

As the temperature increases,
the sublimation becomes more rapid;
and if the heat does not exceed 300° or 330°,
the acid sublimes entirely without decomposition.

At 360°C the sublimation is very free; between this point and 400° it sublimes rapidly; and at 414° it fuses and enters into brisk ebullition.

At temperatures exceeding 330° more o less of the subliming acid,
as the heat is more or less intense,
suffers decomposition; a change immediately indicated by the appearance of water.”

Citation from:
https://books.google.de/books?id=ty...KEwj205iO0sLJAhXCPg8KHaVbBDQ4FBDoAQhfMAg#v=onepage&q=oxalic sublimation&f=false

 

Is the reason for dunking the pan water between hives so each treatment heats up from cold to hot semi slowly?

To the op... if there is that much left in the pan after treatment, isn't the treatment falling short for the volume hive you are treating?

I have gotten my treatment of 3 hives down to 15 minutes from start to finish. I think the faster you can go and minimize disrupting things is better for bee's and beekeepers. I would like to see some science from this company proving that their method kills mites better than traditional vaporizers. To me if there is any oa left in the pan, the treatment is not complete.

 

Is the reason for dunking the pan water between hives so each treatment heats up from cold to hot semi slowly?

No. The reason for dunking the pan in water is because if you put the OA in the pan when it is hot, it will instantly vaporize in your face and not in the hive.

 

Norcalkyle - All I can say is that the treatments were effective based on follow-up testing. I do intend to crank up the heat when I do it again next year to speed up the process. But when I do, I may put a bit less OA in the pan because, as you mention, I was able to achieve the desired effect without vaporizing a full 2 grams.

 

Tagging in. Thanks all