Synopsis: Efficient (i.e. minimal dose, most corpse depend) oxalic acid vaporising entails getting the vapour into the hive and retaining it there. Listed here are some suggestions and tips and the answer to these perished Sublimox seals.

Introduction

The crack IT gurus from Fujitsu and I’ve been manically busy during the last fortnight making the preparations to maneuver this web site to a brand new server . There’s loads to do, ~600 posts and nearly one million phrases, all of which may most likely distilled into a few punchy sentences:

Destroying queen cells isn’t swarm management.

and

Oxalic acid remedy have to be performed when colonies are broodless, which – in winter – is sort of all the time earlier than and never after the New 12 months

OK, there’s a bit extra to beekeeping than that, nevertheless it’s a begin.

As a consequence of all this geekery, gnashing of tooth and bemoaning the dearth of requirements or correct documentation, I’ve been a bit pushed for time. Due to this fact the submit at present goes to concentrate on one factor, hopefully comparatively briefly.

Since it’s now after the New 12 months your bees are more likely to be rearing brood. Mine are. Slowly admittedly, only a small patch on the central going through frames maybe, however sufficient to cover a couple of mites from the harmful impression of oxalic acid.

Sublimox vaporiser

I handled colonies with oxalic acid again in late November; aside from often checking the hive entrances are clear and the burden signifies there are adequate shops within the field, there’s nothing a lot to do till early April .

Nonetheless, in the event that they weren’t rearing brood, or if you wish to deal with with oxalic acid midseason when broodless (e.g. engineered by queen trapping, after swarming, throughout swarm management or for a lately occupied bait hive) then learn on …

Supply strategies for oxalic acid

There are three accepted strategies to use oxalic acid; trickling, spraying or vaporisation (which can also be generally known as sublimation).

For those who learn the directions for Api-Bioxal – the solely accepted oxalic-acid remedy within the UK and USA – these routes are described, albeit with little element of the particular method for use.

On this submit I’m going to solely focus on vaporisation.

Trickling is simpler, there’s much less to get unsuitable, and it’s usually quicker. It’s what I all the time suggest for freshmen, and it’s the tactic I often use. I’ve mentioned it earlier than (and may once more).

Spraying might be not acceptable to be used within the winter as you must take away frames, spray both sides with the oxalic acid resolution and return them to the hive … altogether too intrusive on a chilly winter’s day. It’s additionally not an accepted technique for administering Api-Bioxal oxalic acid within the UK.

Vaporising can also be straightforward, however there are quite a few movies on the internet of how not to do it, or not less than how to not do it effectively.

Lively and passive vaporisation

Vaporisation entails the applying of warmth to powdered oxalic acid dihydrate, ensuing of the conversion of the strong to a gasoline (vapour).

It’s generally known as sublimation as this time period describes the method a bit of extra precisely:

The motion or means of changing a strong substance by heating instantly into vapour with out liquefaction or decomposition, the vapour resolidifying on cooling. Additionally extra broadly: a course of by which a substance undergoes a change of state from strong to gasoline (or vice versa) with out passing by means of the liquid section.

A small quantity of powdered oxalic acid generates a big quantity of oxalic acid vapour.

Due to this fact, if you happen to warmth the oxalic acid in a closed container you get a rise in strain. If the container has a spout or nozzle the oxalic acid vapour is squirted out of the nozzle.

I time period this energetic vaporisation. Possibly there’s a greater time period for it, nevertheless it helps discriminate between the 2 sorts of vaporisers available on the market.

Lively vaporisers embody the Sublimox. That is the machine I’ve:

Chic sublimation

There are a number of different energetic vaporisers and no, I’ve not tried the GasVap, the VarroaBlower or the BioxalSquirtalot. My garments, automotive and perspective have been as soon as trendy … and so was my vaporiser.

The choice to energetic vaporisation is, you guessed it, passive. I exploit passive vaporisation to imply the heating (sublimation) of oxalic acid in an unsealed or open heater, like a small pan.

Passive vaporisers embody the unique Varrox vaporiser (and dozens of lookie-likie imitations):

Varrox vaporiser

Nearly all of the remainder of this submit applies to vaporisation, no matter sort of vaporiser you utilize. The ultimate part is restricted to the Sublimox and can save customers a couple of quid a yr in spares … you’ll be able to thank me later.

Vaporise from the highest or backside?

The general concept with vaporisation is that the oxalic acid vapour is distributed evenly all through the hive and is deposited on all surfaces – wooden, comb, bees and many others. It then lingers for a couple of days, killing any (or as much as ~95%) of the Varroa that come into contact with it.

Sometimes the vaporiser (passive-type) or the vapour (energetic-type) is launched by means of the hive entrance i.e. beneath the frames. Certainly, the directions for Api-Bioxal within the UK and US state:

Place the equipment by means of the doorway of the hive beneath the bees (UK)

or

Insert the vaporizer equipment by means of the underside entrance (US)

My flooring have ‘L’-shaped entrances and so these can’t be used. As a substitute, all of the flooring have a small gap drilled by means of the rear, above the open mesh, permitting me to poke the nozzle of the Sublimox by means of to ship the vaporised oxalic acid. The outlet is often plugged with a small piece of closed cell foam, or a twig, or twist of gaffer tape.

Foam plugged gap and pinned Correx tray

Nonetheless, with an energetic vaporiser you may as well vaporise from above the frames assuming the hive has a little bit of ‘headspace’. Sometimes you’ll be able to present this with a 40-50 mm eke. My reversible insulated polycarbonate crownboards are additionally drilled (just like the flooring) for this goal.

How do I do know this works? I’ve performed it and a bit of little bit of oxalic acid vapour leaks out of the doorway.

I see no motive why a passive vaporiser couldn’t even be used above the topbars of the frames with an appropriate eke, modified to permit introduction of the – usually wider – heating pan. Nonetheless, I’ve not performed this … if in case you have, please touch upon whether or not it really works beneath.

Why would you have to do that?

The higher a part of a vertical cut up maybe, however there are different situations I can consider a effectively.

With no appropriate entrance, or a modification to the ground, it gives a workable different. It’s not clear to me why each the UK and US directions are express about vaporising from beneath. One other case of poor documentation?

Seal the hive correctly

Any oxalic acid vapour that leaks out of the hive is wasted.

There are dozens of YouTube movies exhibiting hives being vaporised accompanied by dense clouds of oxalic acid vapour billowing out of higher or decrease entrances, open mesh flooring, poorly ‘mated’ surfaces between packing containers or different gaps.

Other than being wasted (keep in mind that Api-Bioxal prices ~£0.80 per dose, relying upon the dimensions of packet you buy) all these clouds of oxalic acid are a possible hazard to the beekeeper who isn’t carrying appropriate PPE.

A lungful is loads worse than disagreeable.

Preserve the vapour IN the hive

So … seal the hive correctly, and depart it sealed for not less than 5 minutes after treating to permit all the vapour to settle.

Open mesh flooring

Use a tightly-fitting Varroa tray beneath the open mesh ground to minimise the escape of oxalic acid vapour.

Wonderful Pete Little ground

The perfect flooring I’ve – made by the late Pete Little – have a tray that slides into grooves within the ground runners. These are wonderful. Alternatively, use a sheet of Correx pinned or taped beneath the open mesh ground (see earlier photograph).

I do know some beekeepers vaporise by means of the open mesh ground. Nonetheless, in my expertise a whole lot of the oxalic acid is deposited on the chilly mesh and so doesn’t enter the hive.

Entrances

Any a part of the doorway not getting used to accommodate the vaporiser ought to be sealed.

Entrance block in use …

I exploit an L-shaped wood entrance block that may be a tight match between the Correx touchdown board and the ground, offering a (practically) gas-tight seal. As an apart, these are additionally wonderful when transferring hives.

With passive vaporisers (which often have a broad pan ‘finish’ and a slender deal with/wand) plug any gaps across the wand with a foam block or material.

Theses feedback apply whether or not we’re speaking about hive entrances, or the doorway by means of which the vaporiser is inserted in an eke above the hive physique.

Thorne’s Everynuc

The entire above applies to poly nucs as effectively. Nonetheless, the open mesh ground is commonly troublesome to seal and getting the vaporiser within the entrance can contain a bit of ingenuity.

Bear in mind … the vaporiser will readily soften a poly nuc.

Maisemore’s nucs have a small entrance and a recessed open mesh ground. If you will discover an answer to blocking the latter you may have the ability to modify certainly one of their 14 x 12 ekes to vaporise from the highest.

One of many advantages of Thorne’s Everynuc is that it’s straightforward to vaporise with oxalic acid.

Firstly there’s a fairly tightly becoming Varroa tray.

Secondly, the doorway is so cavernous you can nearly slide the Varrox and the 12 V battery you energy it with inside . So long as you might be cautious to keep away from contact with the poly, there’s adequate area beneath the brood frames to suit the vaporiser pan.

It’s even simpler with the Sublimox.

Everynuc vaporiser entrance adapter

I exploit a lovingly engineered lump of wooden with a gap drilled by means of it to, a) block the doorway, and b) ship the oxalic acid vapour. The (fairly) gas-tight seal across the entrance is aided by a skinny strip of squidgy neoprene foam on the hive-side of the wooden. It really works very effectively.

Wait

It takes a number of minutes for the oxalic acid vapour to settle onto the surfaces throughout the handled hive.

Don’t be in an excessive amount of of a rush to unseal the hive.

The longer you wait – inside motive – the much less vapour will likely be wasted and the much less the colony will likely be disturbed.

For those who take away the doorway block too quickly it’s commonplace to have a number of clearly disturbed bees exit, together with variable quantities of vapour. As a substitute, transfer on to deal with the subsequent hive, and the subsequent … and solely then return and take away no matter it was you used to seal every part up with.

With no escaping vapour and no bees tumbling out of the doorway you could be fairly sure the utmost dose of goodness (until you’re a Varroa) stays within the hive.

The bees will thanks for it.

The mites will likely be much less grateful.

Clustered or not?

In very chilly climate, when the colony is tightly clustered, I desire to deal with with trickled oxalic acid resolution. My justification – made with zero proof – is that the vapour is much less more likely to get right down to the center of the cluster than the answer is.

I often change from vaporising to trickling at 6-7°C, although I’ve vaporised at decrease temperatures and trickled at greater … simply not in a sufficiently managed approach that I may say one works higher than the opposite.

Truly formally testing this isn’t simple (you’d have to know Varroa masses earlier than and after treating, with matched colonies in an analogous state and many others.) so I desire to stay with what’s labored earlier than.

Summer season lovin’ treating

Freshly hived swarms, whether or not newly arrived in a bait hive or dropped right into a skep when bivouacked in a tree, predominantly comprise the youthful bees from the swarmed colony. Consequently, as a result of Varroa primarily associates with youthful bees, these swarms can carry a excessive mite load.

I subsequently routinely deal with them inside a couple of days of hiving them … ‘few’ that means inside the primary week so there may be positively no sealed brood current.

Late night within the apiary

I’ll typically vaporise these swarms late on a summer time night once I could be certain all of the bees are ‘at residence’. Doing it like this ensures all bees are uncovered, however can also be much less disruptive to the colony.

There’s an added benefit … if the swarm is definitely a forged, with a virgin queen, I could be sure she can also be in residence. My bumbling round exterior with the vaporiser is not going to disturb her coming back from an orientation or mating flight.

I’ve not trickle handled at night time. The bees don’t just like the crownboard being lifted after darkish. For those who do, put on a crimson head torch and a full beesuit!

Glucose

Compared to pure oxalic acid dihydrate, the Api-Bioxal bought within the UK is a sub-standard product for vaporising as a result of it accommodates glucose. It’s licensing on this formulation was a disservice to beekeepers and beekeeping. Nonetheless, it’s the one accepted product for vaporisation.

Them’s the foundations.

Within the US the Api-Bioxal is a unique product and solely accommodates 3% of ‘impurities’ (presumably some sort of silica to maintain it free-running) and seems to lack glucose.

Sublimox + Api-Bioxal = caramel

Glucose caramelises at 150°C, effectively beneath the sublimation temperature of oxalic acid. Due to this fact Api-Bioxal leaves a blackened residue of caramelised, burnt glucose within the vaporiser pan.

You’ll be able to keep away from an excessive amount of scrubbing/scouring of the vaporiser pan after use if you happen to line it with aluminium foil.

Foil lined pan

It’s not an excellent resolution and possibly works higher with a pan-type passive vaporiser than my Sublimox, nevertheless it’s higher than nothing. To work effectively the foil must be in shut contact with the heated pan/bowl. If it isn’t the heating is uneven and the vapour manufacturing a lot slower … if you happen to don’t wish to break the foundations, persevere.

Many of the caramel is contained

If any US readers have had points with residues after vaporising Api-Bioxal I’d have an interest to listen to from them.

Sublimox ‘O’ rings

My Sublimox has been nice, working with out situation for years. Nonetheless, it nonetheless wants some periodic upkeep and TLC.

The delrin (?) white plastic cups have an ‘O’ ring seated in a recess across the higher rim which gives a gas-tight seal between the cup and the heated metallic bowl. 230°C and a extremely acidic setting is harsh on these ‘O’ rings they usually ultimately perish, often splitting on the most inconvenient time.

That’s blown it

Inconvenient as a result of you’ve one other dozen hives to deal with and/or the beekeeping suppliers are out of inventory.

I’ve beforehand checked out changing them with ‘O’ rings sourced from engineering-parts provide companies and – due to prompting by ‘common reader’ Elaine – have lastly obtained spherical to sourcing the right dimension.

‘O’ rings are bought in a bewildering vary of sizes, often expressed when it comes to the cross-section and interior diameter. A few of the sizes are metric (e.g. 4mm x 26 mm) and others are described as Imperial, although – confusingly – typically sized utilizing metric measurements.

And, so as to add a bit of extra confusion, typically these measurements are accompanied by an ‘simpler to say although much less informative’ British Commonplace (BS) quantity.

BS215

For the Sublimox you want BS215.

These are ‘Imperial’ ‘O’ rings with a cross-section of three.53 mm and an interior diameter of 26.57 mm.

I arrived at these numbers by a mix of trial and error, correct measurements utilizing digital callipers, and by shopping for and utilizing them.

Different sizes don’t work. Too small and the seal isn’t gasoline tight. Too massive and the plastic cup doesn’t match into the metallic bowl … once more rendering the seal not gasoline tight.

Been there, performed that, obtained the T-shirt.

Silicone and Viton

The manufacturer-supplied ‘O’ rings are constructed from silicone; crimson, fairly versatile, barely shiny in look. They presently value £2 every from Abelo (plus postage). I’ve not looked for higher costs.

I get by means of a few these yearly or so.

You should purchase silicone replacements from eBay from quite a lot of suppliers. I’ve bought from sealsuppliesuk who promote 10 for £4.31, or as little as 17 p every for 50 (together with postage). So far as I can inform these are indistinguishable from these bought by Abelo as ‘official’ Sublimox spares.

Alternatively I’ve now additionally purchased and used BS215 ‘O’ rings constructed from Viton from the identical eBay provider; £8.60 for 10, or 53 p every for 50.

Silicone (left), Viton (proper)

Viton is a Dupont model title (now owned by Chemours) for an FKM fluoroelastomer.

I wager you’re happy you requested.

Viton is black, rather less versatile or compressible than silicone, however BS215 ‘O’ rings match completely.

Viton has a better efficient higher working temperature(PDF) vary than silicone (230°C) and displays elevated chemical resistance; this appeared like a good suggestion since they’re uncovered to the natural acid vapour.

Time will inform whether or not they last more than the silicone ones, however to date they seem to work simply as effectively.

I doubt the enterprise that Abelo may lose on account of this submit will threaten their income … significantly since they’ve been out of inventory for weeks.

Fill your boots