Sublimox vaporiser
For anyone who might be interested in an alternative to Varrox, I splashed out and bought a Sublimox - pricey (around £300), but in my opinion much quicker and easier to use than the varrox. The first time I treated a took along a generator, but Maplin do good inverters - the bumph suggests a 300w one should be sufficient...I bought 600w to be safe, and after an hour of use, the fan hadn't even started to turn, so very comfortably within its limits.
I got mine from Icko in France, but I think Thomas and a few others sell them too. Made in Italy, and unlike 80s Italian motorbikes, the electrics seem to be very good.
Advantages of Sublimox (apart from sheer speed) are:
1) the heat isn't in the hive - vapour is put in by a small copper tube, so there is no scorching damage to frames, bees etc.
2) It isn't necessary to cool it down between hives, as the pod of crystals is below the heat plate until insertion when the whole instrument is turned upside down - the crystals then fall onto the plate and 2g of OA are vaporised in about 30 seconds.
3) The bit to shove in the hive is about 8mm diameter, so much less fiddling around and scorching entrance foam etc.
I have drilled a hole in the side of the floor of each of my hives just big enough to get the copper pipe in (frames are "cold way"). I put in a bit of thin ply to cover the ventilated floor, bung the entrance with a foam strip, insert the pipe and it is done.
Without rushing and on my own, it averages about 2 mins to treat each hive. With an assistant, this would easily come down to 1 minute.
A sublimox would be overkill for just a few hives, but if you have 20 or 30 plus, I reckon it is a good investment.
