making oxalic strips

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just making oxalic gly strips at the mo. borrowed some gear, got some gear in from beequip and as per normal modified it a bit.

as you can see i made a rough stirrer holder. mounted a cheap paint stirrer. please note a mortar stirrer would be better, or at least a low speed paint stirrer. this one i run on low and its not great. i doubt it will last long.

so what the stirrer does is to keep the OA moving and not get to hot on the bottom of the tank. you need about 55c to dissolve everything, but you need to keep under 60c. thats a really really tight window to stay in. go to high (i'm told) that it breaks down into formic acid, which is soluble in glycerin. formic is really hard on bees especially queens. that might explain some of the hive deaths.
it also breaks up the oxalic acid clumps.

the other big factor is humidity. glycerin soaks up moisture when exposed to air. something we want to avoid when the strips are out of the hive as it will start "growing acid crystals" on the surface. that doesn't hurt the bees (as some people claim) but rather its a waste of acid and the strips hold very little acid.. wet oxalic acid kills varroa 3x better than the dry acid on the surface.
making in a damp garage is not a good idea. auckland/northland humidity is really bad for this. need to keep the room super dry.
this also means we want to keep the manufacturing time to a minimum. leaving it to heat up overnight while exposed to air is not good.
do not leave the gly lids off. once the gly soaks up moisture its not useable.

the next thing is we want to keep the strips warm while they soak. so need a room you can keep hot.

so thats why i've set it up in the hot room with the dehumidifier. its only 35c 25% rh.

one downside i found with the kit is the method of keeping the strips in solution. they expand so much it pushes the lid up. the guys we borrowed the gear from started using metal weights instead of the standard method using blocks of wood and weight on top of the lid. something i will look at next time. i would really like to keep the lids clipped on.

also i hear people mentioning different colored strips. they should all be the same. beequip has a poor pic of a tub with different colored strips. it can look like that due to the lights refection, but if you look at a different angle they all look the same IF they stay covered in acid mix.

basic procedure.
put all the gear in the hot room, turn the room heater on and the dehumidifier. test the tank heater and check the thermostat. this one gets it to 55c when set to 60c. thats good so we won't overshoot the temp. remember these are cheap tanks and thermostats drift with age.
leave the gear overnight. that way the gly, acid, strips and water jacket warm up to hot room temp and it speeds up processing time.

turn on heater. set to 60c. i don't see the point of setting it higher and risking overshooting temps. i don't see the need to wait until the water jacket has heated up but it won't hurt.
pour in the gly that you have measured out. it should be runny due to the heat of the room.
turn stirrer on, nice slow speed.
pour in the acid in smallish amounts. break up all the big lumps before you open the bag. i find the stirrer breaks up the chunks but careful to not put to much in at once.
once the required amount of acid is in, its coffee break time. let it heat up and the stirrer will break everything up. come back when the heater light has gone out and check temps.
pour out some mix into a sizeable bucket at full speed. open valve fully, as some acid gets stuck in the valve. probably pour out 5-10 liters or so. tip it back in to mix. let it dissolve in.
coffee time
it should hit 55c and the mix go clear.

set up the containers as per kit instructions.
fill almost to the brim. do not clip the lids on.
check later on once the cardboard has expanded to make sure its still covered. it must remain covered by acid mix at all times. top it off if need be.
btw this is where stainless weights on the strips would be better, make it a lot easier.

leave it overnight.
move strips to draining rack (not drying!). they should all look the same color.
once the excess has drained, off wrap the bundles of strips. do not dry the strips. ideally vacuum pack them. otherwise wrapping in shrink wrap works ok for short term storage. with room at 35c its still very liquid and easy to drain. it should set jelly like at colder temps.

image086.jpg

of course safety gear etc, you will spill acid so be able to clean it. mask for the oxalic dust.
 
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Hi Tristan, the rate of formation of formic acid from oxalic acid is temperature dependent, but I think you need not worry too much in your setup, because at temperatures of 60°C there is no substantial conversion. That only happens at t≥100°C. In many European countries beekeepers use formic acid treatment exclusively to treat Varroa, a low concentration in glycerol would probably not be that dangerous to bees and queens, but certainly formic acid vapour is not to be inhaled. But again, at 60°C and below, that risk is very low.
Re the crystallisation of oxalic acid on the surface of the strips as caused by the absorption of water from humid air: no matter how much one tries to keep the oxalic acid from crystallising, once the strips are in the hives they are exposed to the humid air inside, the glycerol will take up water from the humid air and oxalic acid will crystallise quite quickly (within days). I have never measure hive humidity, but numbers of 55-60% RH are mentioned often. At those humidity levels glycerol can take up ~25% of its weight in water or more and not seldom small puddles of oxalic acid/glycerin/water are seen on the hive bottom or on a sticky board. It can't be avoided.
And finally a question: can you help me with a reference that proves the 3x higher activity of liquid OA in glycerol as compared to the solid?
Thank you, good luck!
 
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its not really about if the higher temps causing formic is actually killing bees or not, its about avoiding risk wherever possible. if you do not need to use higher temps then why take the risk, we can do it as fast and easier without going higher temps.

the moisture in the hive is what makes the strips "work". thats absolutely fine. gly soaks up humidity, acid comes out and gets on the bees/mites.

what we want to avoid is firstly having water in the gly to start with, which upsets our measurements/dosage. but also it soaking up moisture into the strips when being made and in storage. having oxalic come out before we put it in the hive is not useful. these strips hold very small amounts.
now that is something we certainly can avoid quite easly.

remember that we need to make things consistent, so we don't end up with different levels of treatment resulting in widely different outcomes. otherwise you then have hives which simply spread mites to the hives next to it.

the study on the OA look up
Activity of oxalic and citric acids
on the mite Varroa destructor in laboratory assays
Norberto MILANI*
Dipartimento di Biologia applicata alla Difesa delle Piante, Udine University,
Via delle Scienze, 208 – 33100 Udine, Italy
 
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Thank you for the reference, it was not hard to find a pdf. Interesting read! Tests were done on mites extracted from capped cells because results with phoretic mites were too variable according to the author. Still would have been interesting if they had included phoretic mites in their study, that is after all the population Oxalic Acid affects in a hive.

Would you say if crystallisation of OA on the strip surface could be avoided after the strips were introduced inside a hive, that that would be a preferred condition, perhaps in theory?
 
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in the hive the OA gets cleaned off quite quickly. you don't have to try to avoid crystallization inside the hive, the bees do that already. if you look at the parts of the strip the bees cannot get to (or go to), the OA builds up. i've had it a few mm thick. yet the rest of the strip is clean and it works over time quite well. the bees still get the acid on them (randy olivers testing) and mites still die, even tho the strip is clean.

if you look at the amount of OA in a hive after vaporizing, its a lot higher for similar mite kill than OAE. with dry OA you need a lot more. plus bees get rid of dry OA rather quickly. eg vaporizing is only good for 4 days.
so imho having dry OA on the outside of the strip is a waste.

you only have to avoid crystallization on the strip when they are outside of the hive. especially when storing them for a long time.
i've had them on the bench is a dry, medium humidity house and they grow the crystals on the surface.
also had OAE mixture left on the bench and it goes wetter as it absorbs moisture. (and wetter mix gets spread more and ends up being hot and nasty on the bees)
so storing strips open to the air is most certainly not good.
 
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I am interesting in the draining/drying point Tristan - especially as it seems many hives has been poisoned with a staple form that went from soak to hive, without a drying step.
I do wonder whether differences in humidity affect the efficacy of the strips through moisture absorption - especially when @Otto 's instructions (under resources here) state that he dries his gib staples outside for 2 days or so (and aiming for a dry touch). The Beequip instructions say to drain for a minimum of 24 hours.
So the material being used should be carefully noted
 
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I am interesting in the draining/drying point Tristan - especially as it seems many hives has been poisoned with a staple form that went from soak to hive, without a drying step.
I do wonder whether differences in humidity affect the efficacy of the strips through moisture absorption - especially when @Otto 's instructions (under resources here) state that he dries his gib staples outside for 2 days or so (and aiming for a dry touch). The Beequip instructions say to drain for a minimum of 24 hours.
So the material being used should be carefully noted

one thing to keep in mind is these are being packed. they will be unpacked close to time of use. if they are found to be wet extra draining can be done.

i think the hang them out to dry for a few days is poor, but you could get away with it in sunny south island. a damp garage in northland not so much.
no shade on otto here as the "dry" method is pretty common and i'm not saying it can't work. however as i mentioned above i think its a poor thing because of the acid accumulating on the surface. we really want the acid to be in the strip and come out wet, as wet is far more effective. but we also don't want the strips to be dripping as wet strips spreads the acid around far to fast. thats the issue with ratios that have high gly and low acid. they are to wet and tend to be hot on the bees even tho its less acid.

the actual difference in the hive? i don't know. this is all about eliminating things that might go wrong. so we get the same results in different climates.
unfortunately one of the best sources of info is randy oliver, but hes in a very dry place where i doubt that any of this is an issue. plus he also does the 1:1 mix which is dry to touch. a wetter mix in a more humid environment is a bit different.
 
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especially as it seems many hives has been poisoned with a staple form that went from soak to hive, without a drying step.
i would love to hear from those people as to what was actually done.
what mix ratio. what temp where they stored at. a mention of stips in a bag of liquid sort of sounds like a poor ratio. but also could be cold mix soaking for a long time causing the acid to drop out of solution, creating a low acid high gly mix in the strips, which we know is hard on bees.
 
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i would love to hear from those people as to what was actually done.
what mix ratio. what temp where they stored at. a mention of stips in a bag of liquid sort of sounds like a poor ratio. but also could be cold mix soaking for a long time causing the acid to drop out of solution, creating a low acid high gly mix in the strips, which we know is hard on bees.
*Those people* are very quiet Tristan !
Although there have been a couple of people here who have commented on large hive losses, likely through staples that were too wet from their description. But with regard to the large losses in the past couple of years . . .no idea on the recipe

i think the hang them out to dry for a few days is poor, but you could get away with it in sunny south island. a damp garage in northland not so much.
no shade on otto here as the "dry" method is pretty common and i'm not saying it can't work. however as i mentioned above i think its a poor thing because of the acid accumulating on the surface.
Hmm. Not sure I'd agree with your choice of words there Tristan . . .Otto has been using the staples (solely) for a number of years now. Let's just say where Otto is (in Dunedin), it *does* work. Similarly, for others in Auckland . . it appears it doesn't. Also, you're using a different matrix (the strips) versus the staples. It would be interesting to compare
 
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forgive my poor wording.
keep in mind that "it works" and "working the best it can" is two different things.
i need it to work consistently and without failure in every climate. having it "work" is not good enough.

certainly it would be interesting to compare the two materials (and hopefully others as well) but just need to get manufacturing process dialed in first so i can crank them out in large scale.

fyi i had a strip fall out of the pack when wrapping and i left it aside in the hot room overnight. today its actually dry to the touch, to the point that i can handle it and get no meaningful acid residue on my hands/gloves. while these are only drained they are not "wet". they are also not white with acid.
i think the key here is draining them while they are kept warm. it will interesting to see how they are when the packs are opened up at room temp in a few months time.
 
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Thanks for the info guys (y).

Treated all the hives with Apivar this spring which has done an almost good job, but still seeing an occasional sign of mites.

I'm scared of OA/GL strips because of the damage they have done to my bees in the past, but on the other hand having some mites is not good either. So I'm planning to put just one staple in each hive when I super them up, hopefully it will have a repressive effect on any mites present, and not damage the hives. I hope :oops:.

Re the hanging out to dry thing, won't work around here. With our high humidity a freshly made strip hung out would absorb water, not dry.

My own strips I had made from a cardboard material, drying not needed because after the strips are made and packed, they slowly expand until any liquid on the surface is absorbed and they are dry to the touch. I was able to install these strips to the hives without gloves, and also got better results with them than the bought ones.

With this season forecast to be very dry, I am hoping that will also reduce potential harm to the bees from the strips. Very broadly, people who have had success with OA/GL strips have been in lower humidity areas, people who have not have been in humid areas.
 
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Treated all the hives with Apivar this spring which has done an almost good job, but still seeing an occasional sign of mites
thats not good. i suspect there is still some collapsing hives out there from being abandoned/mistreated.

So I'm planning to put just one staple in each hive when I super them up,
one staple won't do any good.
randy oliver has really good research on amount of OA to kill mites in a hive. you need a high enough dose for long enough. also the higher you go the less variability you tend to get. so its a waste of time and money to under dose.

i did notice the strips they supply now are a bit thinner than the original ones that i did the quick and dirty testing on.
still i think the one staple per two frames of brood seams to be a good size. its interesting that they don't touch any strip/side that doesn't have brood near it.
i have a suspicion that we need a strip in every bee gap so each side of a brood frame that is being actively worked on is getting a dose.

of interest that strip i had out of the pack, that was dry to touch. i turned the dehumidifier up so the room humidity went up to 40%, and it started showing white on the outside.
 

Alastair

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Thanks for the info Tristan I'll abandon the one staple idea then. But I am not going to put 4 strips in, for my bees anyway that has always been an extremely bad idea.

Think I will do this instead -

 
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Thanks for the info Tristan I'll abandon the one staple idea then. But I am not going to put 4 strips in, for my bees anyway that has always been an extremely bad idea.

Think I will do this instead -

in my quick and dirty testing i had 8 strips in before any reaction from the bees. they moved away and queen laid in the outside frames.
the hives that died seam to be from the strips i made later which may point to my mistake in manufacturing.
unless there is something else going on, because oxalic doesn't last very long in a hive.

the thymol looks really interesting but the big downside is residue, ie can't do it in a honey flow. i was looking at if i could fit the blocks in the space under the top feeder.
 

Alastair

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Well for me, I use single full depth brood boxes, was thinking of putting them under the excluder. The second box up never comes off it is just winter feed.
 
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Well for me, I use single full depth brood boxes, was thinking of putting them under the excluder. The second box up never comes off it is just winter feed.
from his pics of it, those blocks are way to big to go under an excluder. you would have to use a spacer rim. a feeder rim or two wooden excluder/top mat rims.
hard to say without trying it, but the thymol gel we used years ago made the gear stink for a long time. those supers of feed end up being shifted around and ends up in honey coming off (had a few extraction customers do it). even dead outs being reused as supers the smell stays for a long time. this is why the boss won't let me test it out.
i highly recommend doing it has double brood or single box brood. no supers.
 
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View attachment 1660
View attachment 1661

just making oxalic gly strips at the mo. borrowed some gear, got some gear in from beequip and as per normal modified it a bit.

as you can see i made a rough stirrer holder. mounted a cheap paint stirrer. please note a mortar stirrer would be better, or at least a low speed paint stirrer. this one i run on low and its not great. i doubt it will last long.

so what the stirrer does is to keep the OA moving and not get to hot on the bottom of the tank. you need about 55c to dissolve everything, but you need to keep under 60c. thats a really really tight window to stay in. go to high (i'm told) that it breaks down into formic acid, which is soluble in glycerin. formic is really hard on bees especially queens. that might explain some of the hive deaths.
it also breaks up the oxalic acid clumps.

the other big factor is humidity. glycerin soaks up moisture when exposed to air. something we want to avoid when the strips are out of the hive as it will start "growing acid crystals" on the surface. that doesn't hurt the bees (as some people claim) but rather its a waste of acid and the strips hold very little acid.. wet oxalic acid kills varroa 3x better than the dry acid on the surface.
making in a damp garage is not a good idea. auckland/northland humidity is really bad for this. need to keep the room super dry.
this also means we want to keep the manufacturing time to a minimum. leaving it to heat up overnight while exposed to air is not good.
do not leave the gly lids off. once the gly soaks up moisture its not useable.

the next thing is we want to keep the strips warm while they soak. so need a room you can keep hot.

so thats why i've set it up in the hot room with the dehumidifier. its only 35c 25% rh.

one downside i found with the kit is the method of keeping the strips in solution. they expand so much it pushes the lid up. the guys we borrowed the gear from started using metal weights instead of the standard method using blocks of wood and weight on top of the lid. something i will look at next time. i would really like to keep the lids clipped on.

also i hear people mentioning different colored strips. they should all be the same. beequip has a poor pic of a tub with different colored strips. it can look like that due to the lights refection, but if you look at a different angle they all look the same IF they stay covered in acid mix.

basic procedure.
put all the gear in the hot room, turn the room heater on and the dehumidifier. test the tank heater and check the thermostat. this one gets it to 55c when set to 60c. thats good so we won't overshoot the temp. remember these are cheap tanks and thermostats drift with age.
leave the gear overnight. that way the gly, acid, strips and water jacket warm up to hot room temp and it speeds up processing time.

turn on heater. set to 60c. i don't see the point of setting it higher and risking overshooting temps. i don't see the need to wait until the water jacket has heated up but it won't hurt.
pour in the gly that you have measured out. it should be runny due to the heat of the room.
turn stirrer on, nice slow speed.
pour in the acid in smallish amounts. break up all the big lumps before you open the bag. i find the stirrer breaks up the chunks but careful to not put to much in at once.
once the required amount of acid is in, its coffee break time. let it heat up and the stirrer will break everything up. come back when the heater light has gone out and check temps.
pour out some mix into a sizeable bucket at full speed. open valve fully, as some acid gets stuck in the valve. probably pour out 5-10 liters or so. tip it back in to mix. let it dissolve in.
coffee time
it should hit 55c and the mix go clear.

set up the containers as per kit instructions.
fill almost to the brim. do not clip the lids on.
check later on once the cardboard has expanded to make sure its still covered. it must remain covered by acid mix at all times. top it off if need be.
btw this is where stainless weights on the strips would be better, make it a lot easier.

leave it overnight.
move strips to draining rack (not drying!). they should all look the same color.
once the excess has drained, off wrap the bundles of strips. do not dry the strips. ideally vacuum pack them. otherwise wrapping in shrink wrap works ok for short term storage. with room at 35c its still very liquid and easy to drain. it should set jelly like at colder temps.

View attachment 1662

of course safety gear etc, you will spill acid so be able to clean it. mask for the oxalic dust.
I wouldn’t stress too much about your ozito mixer not lasting, we’ve had one for the last 6+ years for mixing patties up and it’s still going strong! It’s done a few tons of mega bee! I did give it new brushes (supplied!) a couple years ago. N.B. Yet, not too sure about the acidic environment…
 
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I do not think there is one treatment that only has positive effects. If such a treatment existed no one would look for alternatives. But it does not, or at least I do not think we are aware of any, hence our quest for alternatives. I have exclusively experience with Oxalic acid/Glycerol strips largely made following Otto's description available on this forum, with modifications. I felt confident with that approach because we are only a few km's apart so our environments are similar. But because of this one-approach-only-experience I can't compare effects between this treatment and other ones. And even if I had that experience .. the variables are infinite.
All I can say is that over 5 years I never lost a hive to Varroa, even as a novice beekeeper I had one pulling through that had more than 12,000 mites and only OA/GLY was used, it pulled through easily, no thanks to my late detection of the mite invasion.
It is natural and healthy that alternatives are met with healthy criticism. After all we hope for something better and do not like to risk the bees. But none of us know all that there is to be known or even all that may be relevant to a new treatment set up. In my opinion, we can achieve progress by exchanging information of experiences rather than from dogmatic prescriptions.
It is easy to describe one approach and (sometimes rightfully so) be enthused about that approach, but NZ has so many different conditions, climates and microclimates, seasons, bees even, let alone beekeepers and also every year is different. So describing detailed procedures like Tristan did, like Otto did and many others here on the forum and in NZ is really necessary and very useful, but then there are so many details we do not even realise. I hesitate for that reason to share recipes because they may only work "here".

And then there is hearsay which is a always, with all the best of intentions, a derivative of the actual story.

Oxalic acid treatment is in fact a collection of treatments and sometimes mentioned and judged without describing how the active component was applied; each of these will have its own quirks. Drawing firm conclusions about what is best IN GENERAL is tough, if not impossible.

I try to keep observing the colonies when they are being treated and compare different OA/GLY strip recipes. Sometimes you think something works perhaps a little better, as in the mites fall more rapidly, but then again, that hive may have been in a more or less sunny spot, they certainly have different queens and micro genetics at least.

For myself I know I can only try, make mistakes, get up and try more and harder. I think it is called beekeeping :)
 


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