Hi James et al:

I have been treating mites with vaporized oxalic acid for several years. I 
use a set of 5 vaporizers similar to the Varrox one, but using 120 volts 
instead of 12 volts. ( My hives are arranged in rows of five ) I put 2 gm. 
of oxalic acid in each one, put each one in a hive and close the entrance. I 
apply power for 3 minutes, remove and repeat. (sounds like a shampoo 
instruction does it not! ) I can do a yard of twenty in about an hour.

What happens to the acid in the vaporizer is interesting. The first thing 
that happens is that the water of hydration separates from the oxalic 
crystals. Next, as the temperature rises, the water boils off. When the 
water is all gone the temperature of the pan rises and the acid sublimes. l 
don't believe  many acid molecules reach the decomposition temperature, 
because the powder is very fine and the oxalic vapour leaves the surface as 
soon as it vaporizes. I believe that it is all gone before the pan reaches 
the decomposition temperature.

I have a full face respirator, but I find that ordinary splash proof goggles 
and an ordinary paint sprayer mask provide adequate protection. Very little 
vapour makes it out of the hives.

If you can treat when there is little brood, one treatment is probably 
enough. If you have to treat when brood is present, you have to do at least 
three treatments about one week apart to get reasonable control.

Best regards,

Donald Aitken

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