# OAV in cold weather



## Cobbler (Jan 6, 2021)

It seems like I have read a lot of comments that suggest there may be problems using OAV late in the fall when temperatures are in the 40s. Is there some problem using OAV when the bees are loosely clustered - still a few bees venturing out during the warmest part of some days?

I did a full OAV treatment starting in August - every four days, six applications.

Recently I have seen a few more dead or crawling bees outside the hives than I would like to see. I would like to hit them with OAV another time or two. Is there any concern about that?

I am in the Portland Oregon area.


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## johno (Dec 4, 2011)

Whatever the temperature is when you treat with OAV you can do no harm only good. If the outside temperature is around 40 degrees you can be sure with bees flying the temp inside will be higher and even if they are not flying I am sure that the temperature will still be higher.


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## crofter (May 5, 2011)

Put some insulation on and they will not be clustered yet at this temperature.


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## username00101 (Apr 17, 2019)

Isn't the minimum temp 45F?


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## crofter (May 5, 2011)

The temperature inside the hive is the controlling factor in whether or not the bees will be clustered. We are having nights below freezing and my bees, with only top insulation are not clustered. You could wait till a bit later in the day and give a few shots of smoke to stir them up a bit if you had any doubt.


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## Wil-7 (Sep 4, 2021)

Glad I ran across this topic. This my first year with bees, I am planning on doing the OAV in late November or earlier December. Supposedly, no brood. I am in Northeast , Ohio. I do have a BEE Cozy wrap on my hive now because some of our days are getting colder but with an occasional 60* plus day that sneaks in on us. Are there any dangers of doing the OAV with the wand that you stick through the front lower entrance? What should the outside temps be etc. ? I worry that if the bees are to close to the bottom, I'd likely burn their little butts with the hot vapor.


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## crofter (May 5, 2011)

When I was using the wand heaters I found that a few good shots of smoke in the entrance resulted in fewer crispy bees in the bowl. The bee cozy wrap does help, but not near as much as considerably high R value insulation on top. I think I have seen mention in Etienne's literature 60% of heat loss is through the hive top. Foam board under top cover and an extra layer can easily go on top. Various ways of keeping the elements away from the external piece.


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## username00101 (Apr 17, 2019)

Wil-7 said:


> Glad I ran across this topic. This my first year with bees, I am planning on doing the OAV in late November or earlier December. Supposedly, no brood. I am in Northeast , Ohio. I do have a BEE Cozy wrap on my hive now because some of our days are getting colder but with an occasional 60* plus day that sneaks in on us. Are there any dangers of doing the OAV with the wand that you stick through the front lower entrance? What should the outside temps be etc. ? I worry that if the bees are to close to the bottom, I'd likely burn their little butts with the hot vapor.


The wand type vaporizers are not too great. I would purchase a band heater vaporizer, it's the superior OAV application method, anyone who uses OAV would be crazy not to switch to a band heater.

If you go to "for sale" there's one for $200, or Lorob Bees sells them for $300.


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## Wil-7 (Sep 4, 2021)

crofter said:


> When I was using the wand heaters I found that a few good shots of smoke in the entrance resulted in fewer crispy bees in the bowl. The bee cozy wrap does help, but not near as much as considerably high R value insulation on top. I think I have seen mention in Etienne's literature 60% of heat loss is through the hive top. Foam board under top cover and an extra layer can easily go on top. Various ways of keeping the elements away from the external piece.


I plan on topping off my hive with a Hot Box ( Quilt Box) from Kelley Beekeeping, when it gets pretty cold but after I do the OAV treatment because I worry also about the vapors going up and into the top insulation that the hot box provides. Not sure if that is a good idea or not.


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## Wil-7 (Sep 4, 2021)

username00101 said:


> The wand type vaporizers are not too great. I would purchase a band heater vaporizer, it's the superior OAV application method, anyone who uses OAV would be crazy not to switch to a band heater.
> 
> If you go to "for sale" there's one for $200, or Lorob Bees sells them for $300.


I went over to sales like you said to do. I even checked out his videos. I like what I see but I am already invested $175 in the wand type and haven't even used it yet. With the band type,I'd also have to invest in another generator to power it since my very old generator kicked the bucket and went south on me a year ago. They aren't cheap anymore.


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## Cobbler (Jan 6, 2021)

Thanks everyone. It sounds like there’s nothing to worry about using OAV any time of year.

I should say that my bees are probably not clustered - more like they are just staying inside most of the time.

Even if they were clustered, I would think that OAV would still permeate the ball. Am I wrong about that?


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## username00101 (Apr 17, 2019)

the band heater vaporizers just run an extension chord, no big deal, no battery or generator needed.

Get a 500 watt inverter stick it on your car battery with it on, easy.

Home depot sells them for like $50.

I'd return the wand vaporizer or sell it on ebay, and get yourself a band heater.


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## crofter (May 5, 2011)

Cobbler said:


> Thanks everyone. It sounds like there’s nothing to worry about using OAV any time of year.
> 
> I should say that my bees are probably not clustered - more like they are just staying inside most of the time.
> 
> Even if they were clustered, I would think that OAV would still permeate the ball. Am I wrong about that?


That would be overstating the case I think. Not recommended if tightly clustered. That would depend on population and whether any insulation beyond bare wood of hive.


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## Marcin (Jun 15, 2011)

username00101 said:


> The wand type vaporizers are not too great. I would purchase a band heater vaporizer, it's the superior OAV application method, anyone who uses OAV would be crazy not to switch to a band heater.


Other than speed and reduced chance of frying some bees using the wand style, what are the advantages that make the band heater superior?


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## username00101 (Apr 17, 2019)

Don't underestimate the speed, I can do a colony in about 10-30 seconds with the Band Heater Vaps.


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## Arnie (Jan 30, 2014)

Wil, there is nothing wrong with the wand type vaporizers
I used them for years until I got an Easyvap. 

They do take longer, but the wand will put a lot of vapor into the hive. The important consideration is that they kill mites.

Having said that, I was using 2 wands at once and it still took too long. Too many hives, in 3 locations....

If you have a couple hives or so, don't worry.


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## broncorm (Mar 9, 2018)

Cobbler said:


> It seems like I have read a lot of comments that suggest there may be problems using OAV late in the fall when temperatures are in the 40s. Is there some problem using OAV when the bees are loosely clustered - still a few bees venturing out during the warmest part of some days?
> 
> I did a full OAV treatment starting in August - every four days, six applications.
> 
> ...



*What is the outside temperature range to perform OAV?*
You need an outside temperature of 37 (f). There is no top temperature. The temperature of 37 f is only needed at time of treatment and 1-2 hours thereafter.


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## Cobbler (Jan 6, 2021)

What is the reasoning behind 37 degrees minimum to use OAV?


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## username00101 (Apr 17, 2019)

We discussed this last winter. The temperature affects the tightness of the cluster. Below 37F it's so tight the OAV can't get into the middle and the mites are not affected.

The puff of smoke suggestion is a good one, it tends to loosen them up a bit - but 45F-50F is better.


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## crofter (May 5, 2011)

Cobbler said:


> What is the reasoning behind 37 degrees minimum to use OAV?


I am curious too. The bees start to cluster according to temperature in the hive, do they not? How is outside temperature the controlling factor? Where exactly shall the temperature be measured?


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## Kuro (Jun 18, 2015)

Cobbler said:


> What is the reasoning behind 37 degrees minimum to use OAV?


Mann Lake says >40F (Mann Lake® Oxalic Acid Vaporizer), Dedant says 37F (https://www.dadant.com/wp-content/uploads/2012/04/2011/09/Dadant_OxalicAcidVaporizer_QandA.pdf), BetterBee says ‘as low as 37 F, but a better range is in the mid-40s to low50s F’ (How to Do an Oxalic Acid Vaporization Using a Varrox Wand). None of them cite the original literature (if any). 

I use a wand-type vaporizer inserted from the bottom entrance. When the outside temp is >45F, the OA fume mostly leaks out from the top (i.e., the entire hive box gets exposed), but when it is below 40F, the fume mostly leaks out from the bottom.


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## johno (Dec 4, 2011)

I think most of the low temperature story is thumbsuck as nobody has done actual tests where you can see the bees, personally I feel that even if the bees are clustered they will break cluster and mill around from the panic of a sudden intrision of something strange. I think the only time when you could do harm is in the second half of winter when you can get prolonged periods of extreme cold and you would not want the bees to break cluster as they would be likely to freeze.


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## Amibusiness (Oct 3, 2016)

They form a tight band of bees as a skin on the outside of the cluster and heat the inside to whatever temp they need. The thickness of the skin is determined by the outside temp. The amount of space inside the skin determines how productive they can be (how much brood they can rear) coming into spring. The skin is not airtight but is pretty dense. Stating a certain temp is missleading as southern bees seem to form a thicker skin at a higher temp than northern bees. So know your bees and behave accordingly. An observation hive can help give insight but is not a guarantee of what a bigger 3D colony is doing....


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## Fivej (Apr 4, 2016)

I have used a wand for five years and was taught by Enjambres to always give them a couple puffs of smoke to clear them from the bottom board and bottom of the frames. In the fall and winter, I wait until I get a warm day around 40 and up. Usually two or three puffs will get them to loosen their cluster. You can hear them react. Smoke is needed, but don't over do it when it's really cold.


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## Marcin (Jun 15, 2011)

Cobbler said:


> What is the reasoning behind 37 degrees minimum to use OAV?


I've heard that part of the reason. besides tighter cluster, is that below 37 degrees, oxalic acid will recrystallize faster. I've heard this first at a beekeeping meeting. Since then, I've heard it mentioned many times at meetings. When asked for explanation why 37 degrees, the answer was because so and so said so. 
Take that with a spoon of salt. Like most of the stuff said at the back of the room at a beekeeping meeting.


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## johno (Dec 4, 2011)

The oxalic acid is crystalizing within an inch or two of leaving the surface of the pan or nozzle of the vaporizer, and the cooler it is in the hive the higher those crystals will rise until they cool enough to be heavier than air and then they will fall and come to rest on all of the horizontal areas. I have spent quite a bit of time vaporizing into an obsevation hive and watching the vapor flow and the bees reaction, once the vapor comes into contact with bees it looks like absolute panic sets in and it is every bee for itself and they run around all over the frames and as the vapor settles the bees return to normal. From this I would say that unless it was extremely cold when bees without brood could really shut down, they would panic and break cluster for about 5 minutes. As the observation hive never got below 50F I could not put that theory to test and I do not know of anyone has.


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## username00101 (Apr 17, 2019)

Interesting, so clearly damage is done if the temperature is too low. I try rather hard to make sure I NEVER do it on a day colder than 45F. Last year was a cold one, I was forced to do OAV at 40F or so, it worked but I needed to do more than one for it to be effective and kill every last mite.

Recommendation is 50F or above, but one can in theory get away with it at 40F. The warmer the better.


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## crofter (May 5, 2011)

username00101 said:


> <Snip> Interesting, *so clearly damage is done if the temperature is too low.* <Snip>


From what do you draw that conclusion? Was it from johno's post? I have seen nothing so far in this thread about damage; only speculation about loss of effectiveness.


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## johno (Dec 4, 2011)

I just did a check on one of my colonies that had no brood but was queen right, did a treatment and had about a hundred mites fall. That was a surprise as that colony and all my others have had 12 treatments since late July and the last 6 of those finished in late September, makes you think does it not. It would appear that mites are spending more time in the brood than on bees, no question of resistance cause when they were broodless the treatment brought them down. No doubt that I will get them as I do my broodless treatments but they will have done some damage to my winter bees. I will have to re think this treatment next year and maybe split all the hives into hives with capped brood and no queen and hives with queens and no capped brood in around August and see how that improves the treatments.


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## Struttinbuck (Mar 8, 2020)

johno said:


> I just did a check on one of my colonies that had no brood but was queen right, did a treatment and had about a hundred mites fall. That was a surprise as that colony and all my others have had 12 treatments since late July and the last 6 of those finished in late September, makes you think does it not. It would appear that mites are spending more time in the brood than on bees, no question of resistance cause when they were broodless the treatment brought them down. No doubt that I will get them as I do my broodless treatments but they will have done some damage to my winter bees. I will have to re think this treatment next year and maybe split all the hives into hives with capped brood and no queen and hives with queens and no capped brood in around August and see how that improves the treatments.


Want to get a percentage of mites killed? This broodless period will be perfect for that. 
1. Make sure the hive has no brood. Treat the hive. With all bees in the hive.
2. Give the hive a number of days for the mites to fall.
3. Treat again with same or another trusted method.
4. If you have zero mites on the second treatment then your method of treatment killed 100% of the mites.
5. If you have a very low number of mites compared to the first mite count then you can give it a percentage of effectivness.


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## johno (Dec 4, 2011)

Struttingbuck, the problem is to get them broodless well before they have to produce winter bees, this cannot be done by shutting down the queen as the hive will be set back from the lack of brood for 21 to 24 days. But if the hive is split in late summer with the queen and open brood in one half they can be treated immediately and mite population reduced to zero the other half with all the capped brood can be given a queen cell and 24 days later can be treated until mite free. You can leave the young queen with the hive and keep it split or you can remove the young queen make a nuc for her and combine the rest with the original hive and in this way you start going into fall with no to few mitesand still strong populations.


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## Struttinbuck (Mar 8, 2020)

johno said:


> Struttingbuck, the problem is to get them broodless well before they have to produce winter bees, this cannot be done by shutting down the queen as the hive will be set back from the lack of brood for 21 to 24 days. But if the hive is split in late summer with the queen and open brood in one half they can be treated immediately and mite population reduced to zero the other half with all the capped brood can be given a queen cell and 24 days later can be treated until mite free. You can leave the young queen with the hive and keep it split or you can remove the young queen make a nuc for her and combine the rest with the original hive and in this way you start going into fall with no to few mitesand still strong populations.


November is perfect in my region. I have 2 colonies out of 17 that are broodless right now. This next month is going to be a prime broodless period. The winter bees have been laid. They are emerging as we speak. And I can't see much more brood till the maples start blooming. Thats why OAV is an almost perfect form of treatment this time of year. There can be no better time for a single treatment of OAV than November, December. Just make sure they have broke cluster but not out foraging much. One treatment and every mite is dead.


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## bricknerdn (Dec 5, 2020)

Cobbler said:


> It seems like I have read a lot of comments that suggest there may be problems using OAV late in the fall when temperatures are in the 40s. Is there some problem using OAV when the bees are loosely clustered - still a few bees venturing out during the warmest part of some days?
> 
> I did a full OAV treatment starting in August - every four days, six applications.
> 
> ...


Whoa! Everyone using OA vaporization needs to read Randy Oliver's article in the February 2021 issue of the American Bee Journal in regard to the Frank Luttman vaporization trial. Basically Luttman found that he could not bring his mite levels under control until he was doing the vapos every 2 days. This means you might need to do up to 10 consecutive 2 days vapos to get the best mite kill because there are newly emerging mites from the capped brood that exists on the day you started the vaporization. Remember, the just capped drone cells will have mites emerging 14 days after you start this treatment cycle.

Here is the link to Randy's article:









Mite Control While Honey is on the Hive: Part 4 - Scientific Beekeeping


Mite Control While Honey is on the Hive Part 4 First Published in ABJ February 2021 Randy Oliver ScientificBeekeeping.com In the three previous articles in this series, I showed the results of my field trial of summer mite treatments. Now let’s go a little further with extended-release oxalic...




scientificbeekeeping.com


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## snl (Nov 20, 2009)

Cobbler said:


> It seems like I have read a lot of comments that suggest there may be problems using OAV late in the fall when temperatures are in the 40s. Is there some problem using OAV when the bees are loosely clustered - still a few bees venturing out during the warmest part of some days?
> 
> I did a full OAV treatment starting in August - every four days, six applications.
> 
> ...


If you read what Johno wrote, you’ll have your answer.


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## Akovia (Aug 3, 2020)

Cobbler said:


> It seems like I have read a lot of comments that suggest there may be problems using OAV late in the fall when temperatures are in the 40s. Is there some problem using OAV when the bees are loosely clustered - still a few bees venturing out during the warmest part of some days?
> 
> I did a full OAV treatment starting in August - every four days, six applications.
> 
> ...


Ikm a newbie in PDX Metro as well. My five colonies ar also throwing out lots of dead bees. Transition from summer forager bees (they are still bringing pollen in 11/3/21!). I am feeding dry sugar inside Vivaldi boxes. My boxes are “heavy” with resources. One colony seems to be drone heavy and I don’t know what that means (heavy boxes). I have been planning to OAV in early December.


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## Struttinbuck (Mar 8, 2020)

bricknerdn said:


> Whoa! Everyone using OA vaporization needs to read Randy Oliver's article in the February 2021 issue of the American Bee Journal in regard to the Frank Luttman vaporization trial. Basically Luttman found that he could not bring his mite levels under control until he was doing the vapos every 2 days. This means you might need to do up to 10 consecutive 2 days vapos to get the best mite kill because there are newly emerging mites from the capped brood that exists on the day you started the vaporization. Remember, the just capped drone cells will have mites emerging 14 days after you start this treatment cycle.
> 
> Here is the link to Randy's article:
> 
> ...


Thats why the broodless period is so perfect for OA.
And how on earth is it I haven't heard any treatment company, PHD's, organizations or studies speak of how effective any of these treatments are? We need a percentage of mites killed rate. The most feasible way to do that is going to be this broodless period coming up. Unless your in an area that doesn't have a broodless period.


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## bricknerdn (Dec 5, 2020)

Struttinbuck said:


> Thats why the broodless period is so perfect for OA.
> And how on earth is it I haven't heard any treatment company, PHD's, organizations or studies speak of how effective any of these treatments are? We need a percentage of mites killed rate. The most feasible way to do that is going to be this broodless period coming up. Unless your in an area that doesn't have a broodless period.


And most of my colonies have brood year round. The best mite treatment going is Randy's OA shop towels with a fall final treatment using MAQS.


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## Ruggggus (Jun 23, 2019)

Allow me to toss in my experience and conclusions. I waited till mid September when I was done removing honey to begin OAV only because I wasn't aware that the new lable was available on April 30th that allows treatment while honey is on. Had I known I would have started treatments in late July to get mites under control long before winter bees are being produced. Why treat sooner? Because along with weakening the bee from feeding on its fat body the mites also bring disease into the picture and i think the colony can better deal with disease while having a large amount of brood in the chamber and more coming due to the fact that diseased bees will fly away from the colony. The colony can afford this with many new bees to replace them but this is not the case in late fall, at least in upper NYS.
Once I start treatment it continues every 3 days (weather and my schedule permitting) until the mite drop for a treatment is below 50. This is because I have found through watching mite drop counts that two days after a treatment is usually the highest count and drops significantly after day 3. I assume because there is no longer a sufficient amount of OA in contact with the mite. I can tell you for a fact that treating a broodless colony once does NOT kill all mites! Why? I don't know, it can be several things. Maybe the mite is covered by the bees exoskeleton plate enough to drop the amount of OA contact below that required to kill or maybe 1 gram per brood chamber isn't enough to coat each bee with a sufficient amount of OA. Heck maybe there are too many bees in the colony for any amount of OA to find it to the center of the colony. I used to think that the only answer was that scout bees were bringing mites in from a colony outside my control (mite bomb). This is another absolutely a good possibility but not the only one and there are likely others I have not yet thought of. But again I'll tell you that a single treatment will not even kill half of the mites in the hive, I doubt even a quarter of them.
Now for the crux of this thread, outside temperature. As others have hinted at, outside temperature is not what the temperature is inside the hive. I have insulated hives and normal 3/4" pine uninsulated hives and the density of the cluster is much different between them. Know your equipment and what is going on within it by opening it up and observing. You are not going to hurt your bees at all even if it's cold. You will kill brood if you chill it but adult bees are way tougher than we are and can take a lot.
Now back to the difference of a pan vs band heater application method. They are both electric so that is not part of the equation. What is is where the heat generation is. The pan takes much longer and puts that heat producing unit right in the hive where low hanging burr comb can come in contact with it and catch your hive on fire, been done several times. Now the bees are doing there best to maintain about a 95°F temperature in the core. Which do you think is more beneficial to them several minutes of heat build up to get the OA sublimated or 20 seconds. This is why the bees are freaking out, I know I would be if my furnace started blowing 400°F air directly at me. Can they take it? Yes, because they are pretty darn tough but it's our job to do what's best. 
Once you use a band heater you will never go back. There are several of us right here on beesource that make and sell them for close to our less than the cost of a pan, save yourself the frustration of time spent and killed bees. Or make your own from the plans I have on my showcase.


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## Struttinbuck (Mar 8, 2020)

bricknerdn said:


> And most of my colonies have brood year round. The best mite treatment going is Randy's OA shop towels with a fall final treatment using MAQS.


What are the things you like about the shop towels the most so far? Theres a youtube guy named Steves outdoor world thats using them too.


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## snl (Nov 20, 2009)

First, the label has NOT changed! It is still one gram per brood chamber and you cannot use it with harvestable honey
Second the OA coming out of a band heater vaporizer is not all that hot. Johno here on BS has demonstrated that blowing it against his arm.
Third, one gram per brood chamber is inadequate. Cameron Jack at UFL has shown that. I’ve heard that the EPA will allow a greater dose soon, but until then.


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## Struttinbuck (Mar 8, 2020)

Ruggggus said:


> Allow me to toss in my experience and conclusions. I waited till mid September when I was done removing honey to begin OAV only because I wasn't aware that the new lable was available on April 30th that allows treatment while honey is on. Had I known I would have started treatments in late July to get mites under control long before winter bees are being produced. Why treat sooner? Because along with weakening the bee from feeding on its fat body the mites also bring disease into the picture and i think the colony can better deal with disease while having a large amount of brood in the chamber and more coming due to the fact that diseased bees will fly away from the colony. The colony can afford this with many new bees to replace them but this is not the case in late fall, at least in upper NYS.
> Once I start treatment it continues every 3 days (weather and my schedule permitting) until the mite drop for a treatment is below 50. This is because I have found through watching mite drop counts that two days after a treatment is usually the highest count and drops significantly after day 3. I assume because there is no longer a sufficient amount of OA in contact with the mite. I can tell you for a fact that treating a broodless colony once does NOT kill all mites! Why? I don't know, it can be several things. Maybe the mite is covered by the bees exoskeleton plate enough to drop the amount of OA contact below that required to kill or maybe 1 gram per brood chamber isn't enough to coat each bee with a sufficient amount of OA. Heck maybe there are too many bees in the colony for any amount of OA to find it to the center of the colony. I used to think that the only answer was that scout bees were bringing mites in from a colony outside my control (mite bomb). This is another absolutely a good possibility but not the only one and there are likely others I have not yet thought of. But again I'll tell you that a single treatment will not even kill half of the mites in the hive, I doubt even a quarter of them.
> Now for the crux of this thread, outside temperature. As others have hinted at, outside temperature is not what the temperature is inside the hive. I have insulated hives and normal 3/4" pine uninsulated hives and the density of the cluster is much different between them. Know your equipment and what is going on within it by opening it up and observing. You are not going to hurt your bees at all even if it's cold. You will kill brood if you chill it but adult bees are way tougher than we are and can take a lot.
> Now back to the difference of a pan vs band heater application method. They are both electric so that is not part of the equation. What is is where the heat generation is. The pan takes much longer and puts that heat producing unit right in the hive where low hanging burr comb can come in contact with it and catch your hive on fire, been done several times. Now the bees are doing there best to maintain about a 95°F temperature in the core. Which do you think is more beneficial to them several minutes of heat build up to get the OA sublimated or 20 seconds. This is why the bees are freaking out, I know I would be if my furnace started blowing 400°F air directly at me. Can they take it? Yes, because they are pretty darn tough but it's our job to do what's best.
> Once you use a band heater you will never go back. There are several of us right here on beesource that make and sell them for close to our less than the cost of a pan, save yourself the frustration of time spent and killed bees. Or make your own from the plans I have on my showcase.


I totally agree the treatments probably don't kill all the mites. Well I have 5 hives this month I'm going to have a better idea of just how many they do kill . And if other people can do the test too it will start to show us all what treatments are working the best.


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## davemal (Mar 6, 2015)

Below are links to the two OAV videos I made a couple years ago using ProVap 110 band heater.

I am in mid-MD. I treat with OAV only once around Thanksgiving when we are broodless. (I treat prior to this with Apivar beginning July15). My bees are always at the top when I use OAV, so I want a strong cloud of vapor up top where the bees are. Vapor injected at the bottom largely stays there unless moved around by the bees. But the bees do not move it around because they are all near the top, thus my preference is for top-down application.

Watch first: (1260) Experimental OAV treatment of triple deeps - YouTube

Then watch: (1260) ProVap110 experiment on triple deep colony - YouTube


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## Struttinbuck (Mar 8, 2020)

davemal said:


> Below are links to the two OAV videos I made a couple years ago using ProVap 110 band heater.
> 
> I am in mid-MD. I treat with OAV only once around Thanksgiving when we are broodless. (I treat prior to this with Apivar beginning July15). My bees are always at the top when I use OAV, so I want a strong cloud of vapor up top where the bees are. Vapor injected at the bottom largely stays there unless moved around by the bees. But the bees do not move it around because they are all near the top, thus my preference is for top-down application.
> 
> ...


No comparison between the two. Vaping from the top is 10 times more distributed. Good demonstration.


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## bricknerdn (Dec 5, 2020)

Struttinbuck said:


> What are the things you like about the shop towels the most so far? Theres a youtube guy named Steves outdoor world thats using them too.


If you go to Randy Oliver's website, scientificbeekeeping.com, and select "varroa management" from the list on the right side of the page titled "articles by publication date", you will be amazed at the number of articles he has published from his years of research and trials. He was the first person in the US to obtain EPA permission to evaluate the use of OA impregnated into various media, a practice that has been approved in many European and South American countries in many years, but is still not approved by the EPA in the US.

After reading his articles in early 2017, I was convinced this was the only way to go and adopted the shop towel method every year since then. Dribbling is crazy and buying $300 vaporizers was expensive. I applied the towels three times a year in 2017 through 2020, April 1, June 1, and August 1, and then the MAQS in October when temperatures permitted. I sampled every one of my hives at the end of the month, February through November, so I know exactly what the mite populations were at all times. The average mite drop for the entire year 2019 was .6 mites/100 bees, in 2020 was .3 . With those excellent results, I applied the towels twice this year, June 15 and August 15. To date this year, the average is .5 . That result will be lower after I do the November checks since the hives are currently in the MAQS final mite treatment.

The OA towels are a 20 cents per hive treatment. I repeat, 20 cents per hive. Our bee club has had annual losses less than 15% over the last three years since adopting the shop towel method, and some good wintertime feeding regiminens. Don't buy the OA Mann-Lake that sells for like $30 for a small bag. You can buy the same OA on Amazon at a fraction of that cost if you are doing large batches. Likewise, vegetable glycerin can be bought from Bulk Apothecary at excellent prices. 

Need a recipe sheet, email me at [email protected].


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## Struttinbuck (Mar 8, 2020)

bricknerdn said:


> If you go to Randy Oliver's website, scientificbeekeeping.com, and select "varroa management" from the list on the right side of the page titled "articles by publication date", you will be amazed at the number of articles he has published from his years of research and trials. He was the first person in the US to obtain EPA permission to evaluate the use of OA impregnated into various media, a practice that has been approved in many European and South American countries in many years, but is still not approved by the EPA in the US.
> 
> After reading his articles in early 2017, I was convinced this was the only way to go and adopted the shop towel method every year since then. Dribbling is crazy and buying $300 vaporizers was expensive. I applied the towels three times a year in 2017 through 2020, April 1, June 1, and August 1, and then the MAQS in October when temperatures permitted. I sampled every one of my hives at the end of the month, February through November, so I know exactly what the mite populations were at all times. The average mite drop for the entire year 2019 was .6 mites/100 bees, in 2020 was .3 . With those excellent results, I applied the towels twice this year, June 15 and August 15. To date this year, the average is .5 . That result will be lower after I do the November checks since the hives are currently in the MAQS final mite treatment.
> 
> ...





bricknerdn said:


> If you go to Randy Oliver's website, scientificbeekeeping.com, and select "varroa management" from the list on the right side of the page titled "articles by publication date", you will be amazed at the number of articles he has published from his years of research and trials. He was the first person in the US to obtain EPA permission to evaluate the use of OA impregnated into various media, a practice that has been approved in many European and South American countries in many years, but is still not approved by the EPA in the US.
> 
> After reading his articles in early 2017, I was convinced this was the only way to go and adopted the shop towel method every year since then. Dribbling is crazy and buying $300 vaporizers was expensive. I applied the towels three times a year in 2017 through 2020, April 1, June 1, and August 1, and then the MAQS in October when temperatures permitted. I sampled every one of my hives at the end of the month, February through November, so I know exactly what the mite populations were at all times. The average mite drop for the entire year 2019 was .6 mites/100 bees, in 2020 was .3 . With those excellent results, I applied the towels twice this year, June 15 and August 15. To date this year, the average is .5 . That result will be lower after I do the November checks since the hives are currently in the MAQS final mite treatment.
> 
> ...


Plus the stuff from laboratories is 99% pure.


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## username00101 (Apr 17, 2019)

Back to the temperatures. Outside temps must be in the mid to upper 40s and sunny at the minimum. Higher the better obviously, 50s is best - get them when they are not too clustered.

_1 gram per brood chamber isn't enough to coat each bee with a sufficient amount of OA_

1 gram per brood chamber isn't supported by the evidence in the literature that I've read. Research has demonstrated larger doses are highly effective.

_I waited till mid September when I was done removing honey to begin OAV only because I wasn't aware that the new lable was available on April 30th that allows treatment while honey is on. _

The USDA approved OA that is safe to use with harvestable honey is the Api Bioxal -

Just read the EPA label - obviously the EPA agrees with beekeepers that OA doesn't and cannot contaminate honey.


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## zeeksbeees (May 28, 2020)

bricknerdn said:


> If you go to Randy Oliver's website, scientificbeekeeping.com, and select "varroa management" from the list on the right side of the page titled "articles by publication date", you will be amazed at the number of articles he has published from his years of research and trials. He was the first person in the US to obtain EPA permission to evaluate the use of OA impregnated into various media, a practice that has been approved in many European and South American countries in many years, but is still not approved by the EPA in the US.
> 
> After reading his articles in early 2017, I was convinced this was the only way to go and adopted the shop towel method every year since then. Dribbling is crazy and buying $300 vaporizers was expensive. I applied the towels three times a year in 2017 through 2020, April 1, June 1, and August 1, and then the MAQS in October when temperatures permitted. I sampled every one of my hives at the end of the month, February through November, so I know exactly what the mite populations were at all times. The average mite drop for the entire year 2019 was .6 mites/100 bees, in 2020 was .3 . With those excellent results, I applied the towels twice this year, June 15 and August 15. To date this year, the average is .5 . That result will be lower after I do the November checks since the hives are currently in the MAQS final mite treatment.
> 
> ...


Always good reading around here....so the OP was asking about OAV in cold weather and here I am reading about shop towels and MAQS. What are the pros/cons with OAV vs. shop towels. I did see a Provap 110 for $75 so not sure where the $300 comes in. Maybe a whole new thread on shop towels is needed? In fact I am not too sure about what Randy's shop towel technique is and how to do it.


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## Struttinbuck (Mar 8, 2020)

zeeksbeees said:


> Always good reading around here....so the OP was asking about OAV in cold weather and here I am reading about shop towels and MAQS. What are the pros/cons with OAV vs. shop towels. I did see a Provap 110 for $75 so not sure where the $300 comes in. Maybe a whole new thread on shop towels is needed? In fact I am not too sure about what Randy's shop towel technique is and how to do it.


There hasn't been a company, a university study a corporate study on a percent effective rate on any of the treatments that I know of.
Of coarse it would be a difficult task. But this month and next month are perfect times for as many bee keepers that can see the opportunity this giant regional brood break we have coming up to attempt and put together their percentages of sticky board mite drops as possible. Basically it is 2 sticky board tests(Maybe more) and 2 mite treatments. Of coarse it's not like a university study but as Frederick Dunn calls it a citizen study.
1. Make sure hive is broodless
2. Make means and prep a sticky board
3. Install sticky board
4. Treat hive with treatment you want to find percentage effective rate.
5. Give minimum of 3 days for treatment(Or whatever the treatment suggests). Preferably more since hive is broodless.(There can be no mites reproducing since there is no brood)
6. Count the mite drop(Document it)
7. Clean sticky board and reinstall
8. Treat hive again preferably with a different cold weather treatment
9. Wait minimum 3 days again or whatever the treatment you used suggests.
10. Count the sticky board(Document everything possible ,daily temperature is huge)
If the 2nd mite count is higher than the first. The percent effective rate is P>O>S>
If the 2nd mite count is close to or the same as the first it's possibly 50%
If there are zero mites on the second sticky board test it's 100% effective
Ex. 1 first mite drop 90
2nd mite drop 10
With those results you can be reasonably sure you killed 90% of the original pheretic mites.
The more tests done and the more people that do them well documented , the better the information you will start finding as to which treatments are the most effective.


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## bricknerdn (Dec 5, 2020)

zeeksbeees said:


> Always good reading around here....so the OP was asking about OAV in cold weather and here I am reading about shop towels and MAQS. What are the pros/cons with OAV vs. shop towels. I did see a Provap 110 for $75 so not sure where the $300 comes in. Maybe a whole new thread on shop towels is needed? In fact I am not too sure about what Randy's shop towel technique is and how to do it.


I don't follow current pricing on Provap, but when they first became available, they were expensive. Is the $75 one you saw a used device. There are now other manufacturers of vaporizers so I suspect Provap may have become more competitive. Any vaporizing tool using electrical power to operate also requires a generator if the apiary is not close to the power source.

You need to read Randy's article completely. The advantage of shop towels over vaporization is that the towels provide a month's exposure to OA, vaporization only works for several days. If you do vapo once a week, you are missing those mites that hatched latter in the week and re-invaded those larvae that are ready to cap. That's why the effacacy of vapo is not good enough to get a hive ready for winter.

Randy has several years of articles on oxalic acid shop towel trials. There is absolutely nothing negative about this method. This year and last he has also conducted trials using Swedish sponges in place of the blue Scott shop towels. I suspect he will have some good articles in the ABJ this winter with those trial results. My trials with the sponges were good. The mites do not chew up the sponges like they do the shop towels, so you only need to make one application early in June here to last until the October MAQS application. The cost for the sponge maybe higher than shop towels, but when your hives are 6 and 7mediums high, not having to remove all of those upper boxes to get down to the brood box on the bottom (in the summer heat) is a blessing in disguise.

I make a roll of 3 towels at a time. I pull 3 full towels off of the roll, fold them over to the size of one towel, and then cut the folded towel in half. The two halves are then rolled up like a roll of toilet paper so your have a roll about 2.5" in diameter by 6" long. This makes it real easy to place into the glass jar with the OA/glycerin solution. About one minute after insertion, the roll is removed and turned over and placed back into the jar to finish absorbing the solution.

Observe the safety precautions because of the solution temperature . Applying the towels in the field does not require all the safety equipment. I handle the towels with my 9 mil nitrile gloves and just wash my hands off with water after the application. I have handled them bare handled many times and never experienced any problem unless I had a tiny cut on a finger and then noticed a slight burning sensation which disapears after washing.


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## bricknerdn (Dec 5, 2020)

username00101 said:


> Back to the temperatures. Outside temps must be in the mid to upper 40s and sunny at the minimum. Higher the better obviously, 50s is best - get them when they are not too clustered.
> 
> _1 gram per brood chamber isn't enough to coat each bee with a sufficient amount of OA_
> 
> ...


A friend who keeps about 70 colonies was applying 2 grams in his vapos. He bought larger cups that now allow hive to apply 4 grams.


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## bricknerdn (Dec 5, 2020)

Struttinbuck said:


> There hasn't been a company, a university study a corporate study on a percent effective rate on any of the treatments that I know of.
> Of coarse it would be a difficult task. But this month and next month are perfect times for as many bee keepers that can see the opportunity this giant regional brood break we have coming up to attempt and put together their percentages of sticky board mite drops as possible. Basically it is 2 sticky board tests(Maybe more) and 2 mite treatments. Of coarse it's not like a university study but as Frederick Dunn calls it a citizen study.
> 1. Make sure hive is broodless
> 2. Make means and prep a sticky board
> ...


If you have followed Randy Oliver's research over the last 5 years, you will find that from his trials and other global research, there is data on the efficacy rates for all of the synthetic and natural miticides, and by the methods they are applied. I do all of my month end mite checks via the sticky board method. I question I have posed to Jerry Hayes, Jennifer Berry, and a number of the nationally recognized experts was, "at what mite count via the sticky board method do you begin mite treatments?" since this is not the widely accepted 3 mites per 100 bees limit. I now take my monthly mite count and factor in the expected bee population for that month, as it obviously changes every month of the year. That population data was obtained from Randy's data library also.

I achieve 99.9%+ mite control in my colonies with the OA shop towel and MAQS applications and have not lost a colony to mites since 2013.


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## blain1976 (Jun 8, 2019)

Wil-7 said:


> I went over to sales like you said to do. I even checked out his videos. I like what I see but I am already invested $175 in the wand type and haven't even used it yet. With the band type,I'd also have to invest in another generator to power it since my very old generator kicked the bucket and went south on me a year ago. They aren't cheap anymore.


Harbor freight sells a generator for around $100 that will easily run the band type vaporizers. Actually as I look now it says clearance $99.97. Not sure if they are doing away with that generator or maybe a newer version is coming out...no telling.


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## johno (Dec 4, 2011)

Amazon or Harbor Freight could supply you with a 500 watt inverter that you clip onto your car or trucks battery at around $30 to $40


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## bricknerdn (Dec 5, 2020)

blain1976 said:


> Harbor freight sells a generator for around $100 that will easily run the band type vaporizers. Actually as I look now it says clearance $99.97. Not sure if they are doing away with that generator or maybe a newer version is coming out...no telling.


And if is made in China, how long do you think it will last?


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## johno (Dec 4, 2011)

Actually most everything sold in the US is made in China anyhow.


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## bricknerdn (Dec 5, 2020)

johno said:


> Actually most everything sold in the US is made in China anyhow.


Regrettably!


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## Struttinbuck (Mar 8, 2020)

bricknerdn said:


> Regrettably!


I think the sticky board is currently the most accurate way to count dead mites because it is taking into consideration the entire hive. Every pheretic mite that dies should drop to the sticky board. (They won't but mechanically they should.) Then for the next few days mites emerge from the capped brood. The alcohol wash is such a focused single area to test. And still only testing pheretic mites. Maybe the alcohol test on a drone brood section of the hive would make it more accurate. Today the temperatures are right for me to clean my sticky boards and run a treatment with the OCV. Then Monday Tuesday do the mite count and another treatment. I may treat with a couple different types the second time depending what the weatherman says.


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## Struttinbuck (Mar 8, 2020)

bricknerdn said:


> If you have followed Randy Oliver's research over the last 5 years, you will find that from his trials and other global research, there is data on the efficacy rates for all of the synthetic and natural miticides, and by the methods they are applied. I do all of my month end mite checks via the sticky board method. I question I have posed to Jerry Hayes, Jennifer Berry, and a number of the nationally recognized experts was, "at what mite count via the sticky board method do you begin mite treatments?" since this is not the widely accepted 3 mites per 100 bees limit. I now take my monthly mite count and factor in the expected bee population for that month, as it obviously changes every month of the year. That population data was obtained from Randy's data library also.
> 
> I achieve 99.9%+ mite control in my colonies with the OA shop towel and MAQS applications and have not lost a colony to mites since 2013.


Would you have a link to any of the data as far as percent effective rates? I tried to search for it on the scientificbeekeeping website. And that man is a WORKHORSE! The DUDE is doing everything he can do to rid us of the mites for sure. Just he has so much info I couldn't locate it.


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## bricknerdn (Dec 5, 2020)

Struttinbuck said:


> Would you have a link to any of the data as far as percent effective rates? I tried to search for it on the scientificbeekeeping website. And that man is a WORKHORSE! The DUDE is doing everything he can do to rid us of the mites for sure. Just he has so much info I couldn't locate it.


I can't remember which of the monthly articles he had that data in and it would take a good amount of time to find it again. 
If you notice on the scientificbeekeeping.com webpage he shows a diagram that he calls the 'Varroa Control Model'. I have downloaded this and adapted the variables to my location. This is a very complex varroa monitoring tool and within its pages is a lot of data Randy has inserted from the sources he has researched, and I know there was some data in there about the efficacy of mite treatments.

I clean my sticky boards with Dawn dishwashing liquid after a test. If one gets gummed up enough with propylis, I clean it off with acetone. Some boards are probably 4 years old and our local Amish wooden ware maker sells them for $1 each so you can throw them away without any significant loss when they get it poor shape.

Since the University of Georgia has expanded the oxalic acid EPA approved testing started by Randy (and some other groups), I expect we will see them approving the use of shop towels and like materials in the next two years.


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## rsmitheyjr (Jan 7, 2022)

username00101 said:


> The wand type vaporizers are not too great. I would purchase a band heater vaporizer, it's the superior OAV application method, anyone who uses OAV would be crazy not to switch to a band heater.
> 
> If you go to "for sale" there's one for $200, or Lorob Bees sells them for $300.


I just bought a OAV UNIT from Lorob bee and it was $274.00 and Rob is very easy to deal with.


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## username00101 (Apr 17, 2019)

Lorob's a good vaporizer. I second that one.


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## tokyfm (Jan 8, 2022)

Put some insulation


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## Ruggggus (Jun 23, 2019)

davemal said:


> Below are links to the two OAV videos I made a couple years ago using ProVap 110 band heater.
> 
> I am in mid-MD. I treat with OAV only once around Thanksgiving when we are broodless. (I treat prior to this with Apivar beginning July15). My bees are always at the top when I use OAV, so I want a strong cloud of vapor up top where the bees are. Vapor injected at the bottom largely stays there unless moved around by the bees. But the bees do not move it around because they are all near the top, thus my preference is for top-down application.
> 
> ...


These are awesome videos, you mentioned checking the temperature increase within the hive during a treatment, did you ever do this. I am aware that you can get the plume quite close to your arm depending on the force and amount of OA that is exiting the nozzle but question what it does in the enclosed small area of a hive. You have encouraged me to start doing my own experiments. I make my own screened bottom boards that the removable panel seals to the bottom board on the front and sides with only a slight gap at the rear (which can be sealed by upward pressure while treating) and I don't have the plume falling out the bottom. I tell everyone they need to use screened boards to get mite counts but didn't realize how much product is lost through the store bought units. I also open the telescoping cover to create a chimney affect till the plume is rolling out the top. After doing some experiments to satisfy my concern of causing too much temperature increase I may switch to an upper application. I also may build a set of plexiglass hive bodies to better understand exactly what is happening within the hive. I have not tried Randy's shop towel method but will look into it further on his web site. Thank you for your post.


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## johno (Dec 4, 2011)

Just get the one that is already insulated, probably the fastest and most efficient one out there.


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## johno (Dec 4, 2011)

And by the way I have had more than 10 years out of my chinesium inverter.


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## Ruggggus (Jun 23, 2019)

johno said:


> And by the way I have had more than 10 years out of my chinesium inverter.


My Chinesium inverter died last year so I switched to my Japanesium 300W generator (yes 300W, it's just supposed to power a halogen light but you can unplug it and plug in the OAV) I know, off topic, please forgive me.


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## Wil-7 (Sep 4, 2021)

tokyfm said:


> Put some insulation


What type of insulation do you suggest for a band heater?


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## Ruggggus (Jun 23, 2019)

Wrap it with fiberglass rope. Used to seal stove doors. Creating an exterior OAV treatment device


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