Treating the same hive with immediately-repeated 1-gram vaporized doses of oxalic in a posturing attempt to comply with the letter of the EPA regs, while completely undermining the spirit of the regs is rather like backing up on a one-way street with the front of the car facing the correct direction, but the actual motion being in the opposite direction.

When stopped by the police for this unusual behavior, the excuse will inevitably be "But I was only going One Way..." 

Personally, I do not see any evidence with my own hives for a need to vaporize more than 1 gram, and more than once every few weeks through winter, but I have smaller NWC clusters, so there are less bees in the cluster, and less total varroa to kill.    But to each his own.  

Again, the "effective dose" seems to be a slippery thing, and that's not surprising, as I don't think people are actually getting a valid "dose" when they think they are - so many vaporizers have only a mass of metal to slow down the temperature rise, and thereby assure a fixed amount of actual sublimation of Oxalic, rather than overheating and boiling the OA.  (As I recall, Medhat was involved in the prototype for a temperature-controlled OA device, but it could not compete with the far cheaper uncontrolled devices, and/or the devices claimed to rely on a mass of metal as their sole "thermostatic control".)

In fact, it is pretty darn easy to precisely control the heat produced by a diesel engine glow plug, and reliably deliver that heat to a small metal dish, and one can fabricate these using off-the shelf hobbyist products intended for grade-school kids.  Use any $2 processor you like, with a PT100 RTD (good for even -200 C to +600 C) and a converter like the MAX31865, which has a SPI interface.  The relay has to be beefy enough to handle the current drawn by the glow plug, so the easy approach is to get a glow plug and its associated relay from a junkyard/salvage yard.  Lots of scrapped diesels out there, and the glow plug relay is invariably under the dash on the driver's side, (it’s the one with six small metal tabs and one big fat one).  Lot's of manuals and videos online.  If all this sounds too complicated, go find the kids at the local "maker club", which tend to meet after school or at the library.  If you bring them the glow plug and relay, they might solder up your toy and write your control code for you.





  

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