# OAV Treatment with Screened Bottom Boards and Inner Cover



## HoovesAndHoney (Feb 23, 2015)

I'm getting ready to run an OAV treatment on our hives. I have screened bottom boards and screened inner cover. What do i need to do in preparation for an OAV treatment with this setup? Thanks in advance for your responses


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## snl (Nov 20, 2009)

You need to close off the bottom board so the vapors do not escape. Insert your tray under the SBB during vaporization for 10 minutes and you're fine.
No problem on the SIC, leave as is or remove during treatment, you have a top cover.


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## HoovesAndHoney (Feb 23, 2015)

Thanks. In your opinion, what is best applicator for the OAV? One that you can dip in water between treatments? I'm running 40+ hives


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## snl (Nov 20, 2009)

HoovesAndHoney said:


> Thanks. In your opinion, what is best applicator for the OAV? One that you can dip in water between treatments? I'm running 40+ hives


For that many hives, the new ProVap110. Fastest on the market. No water dipping at all. View the video.


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## johnwratcliff (Feb 24, 2015)

Varrox is a great wand. On the subject of screen bb's I don't think that you have to seal it off. Read Randy olivers research


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## snl (Nov 20, 2009)

johnwratcliff said:


> Varrox is a great wand. On the subject of screen bb's I don't think that you have to seal it off. Read Randy olivers research


Yes it is, but with 40 plus hives, the ProVap is the best choice. I'd still close the bottom. It's the vapors that kills.


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## JeffM17 (Jul 19, 2013)

What are your thoughts about using the OAV wand below the screened bottom board? I was thinking of making up a solid bottom board insert with a metal flashing then using it to apply the OAV from below the Screen bottom board. I would just block off the normal entrance with a rag. Seems like a easy way to do it...


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## dudelt (Mar 18, 2013)

Others have commented on vaporizing under the screen and the general consensus is to not do it. Some of the vapor solidified on the screen and it appears that it reduces the effectiveness.


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## MichiganMike (Mar 25, 2014)

JeffM17 said:


> What are your thoughts about using the OAV wand below the screened bottom board? I was thinking of making up a solid bottom board insert with a metal flashing then using it to apply the OAV from below the Screen bottom board. I would just block off the normal entrance with a rag. Seems like a easy way to do it...


That is how I do it and it very effective. I should add that I use metal tape to prevent my lower insert from being burned.


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## missybee (Sep 6, 2014)

We are vaporizing under the screen, set up a solid board below the screened. During the last OAV we had burn marks on a frame and melted wax. Going to keep it away from the frames from now on. 

We have been using it for 3 years now.


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## JeffM17 (Jul 19, 2013)

missybee said:


> We are vaporizing under the screen, set up a solid board below the screened. During the last OAV we had burn marks on a frame and melted wax. Going to keep it away from the frames from now on.
> We have been using it for 3 years now.


Did you have the burn marks and melted wax with the wand under the screen? I have a slatted board so Im thinking that plus going under the screen bottom board should reduce / eliminate any chance of a hive fire.


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## missybee (Sep 6, 2014)

JeffM17 said:


> Did you have the burn marks and melted wax with the wand under the screen? I have a slatted board so Im thinking that plus going under the screen bottom board should reduce / eliminate any chance of a hive fire.


No that was through the hive entrance on top of the screen. Two of the hives had burn marks on the bottom of a frame, one was charred enough to be close to flame. That is when we decided to modify our bottom boards. I now have screened bottoms with a solid bottom below, sort of like putting them on a backwards solid bottom board. I made the solid bottoms. I slide in that plastic sign type stuff, to catch debris and be able to dump it. 
So now when we OAV we will enter from the back under the screened bottom board. We will close off the front entrance on all of the hives and won't need to open to stick the wand in. We will close off the back opening once we insert the wand. 
Might be a bit easier, no more bees escaping as we try to get the wand in and out. They sure can escape fast. 

Those two burn marks worried us enough I remade all the hives bottom boards. Now the wand can not get anywhere near the frames or wax.


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## Mike Gillmore (Feb 25, 2006)

JeffM17 said:


> What are your thoughts about using the OAV wand below the screened bottom board?


I built my own screened bottom boards to treat from the back of the hive and have been vaporizing for several years from under the screen. Yes, a small amount of crystals stick to the screen just above the pan, but not enough to impact effectiveness. The vapor fills the entire cavity very well.


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## missybee (Sep 6, 2014)

I used a paint stick, piece of wood and knock any hanging burr comb, etc away before we OAV'd. Even with doing that we had the burn mark. 

We both decided it was time to change our method. 

Glad to hear it will work Mike G we just changed all the bottom boards and have not done a OAV. Good cold weather work. We had enough screened bottom boards so I could convert 4, then go out and do a swap. We had some nice 70 f days to make it safe for the bees.


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## Mike Gillmore (Feb 25, 2006)

Thought I would mention that I use #8 hardware cloth on my SBB's, 1/8" diameter openings. The vapors pass right up through it. Using a narrower diameter screen opening, like window screen type material, could restrict some of the vapor from easily passing through.


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## igottagetalife (Feb 19, 2012)

with screened bottom boards, you would want to close them off with something other than cloroplast slide ins (melt if you get to close). Personally using vapor doesn't work as it is costly. I prefer the drip method (1:1 sugar water 3.5% oxalic acid.


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