Gasvap Modifications

[Newbeeneil]

Indeed!

 

[jeff33]

Maybe I am doing it wrong but 4.3min to sublimate 2.5gr? When the gasvap has reached optimum temperature it takes me less than a minute per hive.

 

[blackcloud]

True - and if you observe through perspex you can see the actual discharge time is usually less than 15 seconds.
Warm weather will keep the vapour swirling for the same duration again.Cold weather has it drop almost instantly(and instantly down through an omf if you administer through the entrance!)
Reassembly, strap-down and breakdown of the next hive takes longer than the dosage itself.

I think the four minutes must include a cuppa and chocolate hobnobs.

 

[Ian123]

Maybe I am doing it wrong but 4.3min to sublimate 2.5gr? When the gasvap has reached optimum temperature it takes me less than a minute per hive.

New equipment these days!!…. I think much of the older research would have been done with the old pan types. Back then it was much faster to trickle.

 

[sean-a]

David Evans summarised his view of the research regarding OA dosage in November last year (mostly in the part headed "Dosage, again", but there's interesting stuff in the comments too):

Repeated oxalic acid vaporisation - The Apiarist

I'd read it as suggesting that a 4g dose will kill a higher percentage of mites, but it may not be a sufficiently large increase over 2g to make a real difference and that more research is probably required into dosage, timing and probably other variables too (hive volume, perhaps, given that the US recommendation is based on the number of brood boxes).

I'm really not sure that increasing the dosage is giving the anti-vaping brigade that much more ammunition than using a non-approved product or performing repeated applications (even with an approved product) mind...

James

The charts presented in the article seem to show that 4g is better than 2g if reducing mite levels is your objective.....
Yet to see any evidence that higher dose (sublimation) is bad for bees.

Interestingly Api-Bioxal is recommended in the article as a once a year treatment (at 2.25g) when vaporising it but....
twice a year when trickling.
Others (Bob Binnie et al I think) seem to suggest that trickling more than once a year damages queens and there is a higher failure rate.

So JBM is right in his assertion that "so no real evidence that the extra few percent can be taken as an across the board figure anyway" as there appear to be few studies and particularly as the lower dose of OA (1.125g) produced higher efficacy than 2.5g.
Most Bee keepers (that use OA sublimation) would not hold to the recommendation that OA is only used as a once a year hit, indeed Bob Binnie talks of doing 8 treatments 3 days apart as an experiment that he is planning. (In the comments under one of his videos)

As in most things Beekeeping.....there is no concensus but plenty of experts willing to put forward their views as fact based on folklore and hunch.
I read that University of Georgia was planning to test higher doses of OA, so I guess that the jury is still out.

 

[Ian123]

"Pete Little (Hivemaker) did some experiments increasing the dose above the recommended levels and found that there were no obvious signs of distressing the bees but ... increasing the dose did not show any improvement over the mite killing"

This is not a controlled experiment, peer reviewed and published in an academic journal. I know because I have looked for it in scientific journals and it has not been published.

I’m pretty sure I could imagine his response to that

 

[pargyle]

I’m pretty sure I could imagine his response to that

I think he'll be looking down and muttering ....he didn't suffer fools lightly. I don't know anyone who had more PRACTICAL experience of sublimating OA ... if his recommedation was for 2.5gms - good enough for me.

 

[JamezF]

Interestingly Api-Bioxal is recommended in the article as a once a year treatment (at 2.25g) when vaporising it but....
twice a year when trickling.

That's because it's what's in the instructions for using Api-Bioxal. I assume using it any other way isn't legal.

James

 

[polymath]

Right.... for any beginners reading this and taking any notice of Sean-a's personal opinion. Please note ... the proven and recognised dosage for treatment of varroa by sublimating oxalic acid is 2.5 gms per colony.

There is no benefit from overdosing and none of the manufacturers of authorised OA treatments and those people who have investigated and tested unauthorised treatments recommend using any more than 2.5 gms.

Sean-a is entitled to his personal opinion but please accept that it is just HIS PERSONAL OPINION and should not be followed.

To be more scientific on this:
https://theapiarist.org/wp-content/uploads/2019/06/Radetzki_OA_vaporisation_trial.pdfhttps://theapiarist.org/repeated-oxalic-acid-vaporisation/
The bottom line is VMD only allow one treatment per year, research has shown multiple treatments are fine. As far as dosage is concerned and there is more research by LASI on this i have not linked to there are no major downsides to slightly higher dosage and under dosing also does not have major issues. But have a read of the attached links.

 

[polymath]

David Evans summarised his view of the research regarding OA dosage in November last year (mostly in the part headed "Dosage, again", but there's interesting stuff in the comments too):

Repeated oxalic acid vaporisation - The Apiarist

I'd read it as suggesting that a 4g dose will kill a higher percentage of mites, but it may not be a sufficiently large increase over 2g to make a real difference and that more research is probably required into dosage, timing and probably other variables too (hive volume, perhaps, given that the US recommendation is based on the number of brood boxes).

I'm really not sure that increasing the dosage is giving the anti-vaping brigade that much more ammunition than using a non-approved product or performing repeated applications (even with an approved product) mind...

James

Some other light reading on this attached and below in links.


Towards integrated control of varroa: effect of variation in hygienic behaviour among honey bee colonies on mite population increase and deformed wing virus incidence : Sussex Research Online

 

[Buzz Off]

Gland pliers Snap!

Thanks..I didn't know what it was called

 

[JamezF]

Thanks..I didn't know what it was called

I've heard them called all sorts of names. Gas pliers, adjustable pliers, "those bloody things over there!"...

James

 

[blackcloud]

pump pliers!

 

[JamezF]

pump pliers!

Oh, yes, I'd forgotten that one.

James

 

[polymath]

Using the gasvap 13mm end cap measure spoon OA is approx. 1.15g - 1.3g per level fill if one just scoops up a level loose fill. A compacted fill by tapping the spoon to settle the OA it is 1.55g - 1.6g.

If one uses Api bioxal a level spoon is 1.6 - 1.65g.

A 22mm end feed cap contains 5.5g approx. of OA compacted by tapping it and 6.3g of Apibioxal.

For OA dosing two spoons of the loose fill method is needed or if using Apibioxal 1.5 spoons. If one is tapping and compacting the measure spoon then also 1.5 is the dose for 2.4 - 2.5g of OA.

Better still instead of guessing or over dosing, weigh your own samples to check and get the dose correct.

really useful thanks thought the point of the measuring spoon supplied by Gasvap was it put the right amount it, why not make it the right size aaaagh. Really great thanks.

 

[pargyle]

really useful thanks thought the point of the measuring spoon supplied by Gasvap was it put the right amount it, why not make it the right size aaaagh. Really great thanks.

It's because just about all the bits of the gasvap are made from standard copper fittings ... the 'scoop' is either an 8mm or 10mm copper pipe end cap. The next size up would be 15mm which is too big. Making a bespoke measure that also serves as a pipe cleaner for the nozzle would be prohibitively expensive.

It ain't rocket science to make your own - a clear plastic tube with a mark to show where the correct weight is .. we don't need to be spoon fed every last bit of kit do we ?

 

[JamezF]

we don't need to be spoon fed every last bit of kit do we ?

Ho ho. I see what you did there

James

 

[hemo]

really useful thanks thought the point of the measuring spoon supplied by Gasvap was it put the right amount it, why not make it the right size aaaagh. Really great thanks.

As has been said the simple use of standard copper fittings makes an exact measure not possible.

My post is that of my own simple findings so that I know my meausres are in the ball park of 2.4 - 2.5g per application.
Others should do the same just to confirm true or not if the amounts used give similar results.

The loose fill example of the 15mm end cap spoon is just that with generic OA , a simple scoop up levelled off with no compacting, I did this three or four times and got a varying weight by 0.15g.

As I mentioned two loose measures of OA is sufficient or 1.5 of Apibioxal.

If one wants an end cap spoon which measures 2.5g in one go then solder a 22mm cap to the 6/8mm pipe and then cut the end cap down in height to where 2.5g of loose fill will sit.

 

[hemo]

Maybe I am doing it wrong but 4.3min to sublimate 2.5gr? When the gasvap has reached optimum temperature it takes me less than a minute per hive.

Even a pan is only 3mins or less to sublimate 2.5g.

 

[polymath]

It's because just about all the bits of the gasvap are made from standard copper fittings ... the 'scoop' is either an 8mm or 10mm copper pipe end cap. The next size up would be 15mm which is too big. Making a bespoke measure that also serves as a pipe cleaner for the nozzle would be prohibitively expensive.

It ain't rocket science to make your own - a clear plastic tube with a mark to show where the correct weight is .. we don't need to be spoon fed every last bit of kit do we ?

No but useful when you buy it for it to say it is not the correct size for 2.5mg sort of just assumed it was. Thought the designer had worked through that. on a bigger pipe they could have just cut the height down to the right size.