I read about the use of a double screen for several purposes on the Imire shim string.
A double screen board is sort of like a Imire shim with screen on both sides and another 3/8" spacer on each side. It leaves a bee space on each side and does not allow the bees from either side to contact one another. It also, usually has some toggle entrances. It can be used for several things. You can use it to put a weaker hive on top of a stronger hive so they can share the warm humid environment, especially over winter. You can put some emerging brood and a new queen cage above the screen, open an entrace in the back for cleansing flights and the emerging brood will be more accepting of the queen than the field bees coming and going below the screen. You can use it to make a combine by putting one hive above and the other below until they are used to each other's scent. I think I'd still put the newspaper between when removing the screen, but it's more of a sure thing. Newspaper combines almost always work, but I have heard of a couple of instnaces that they failed miserably where the strong hive killed off the weak one.
If using for requeening, here is my first question... For how long would one leave the double screen on, after introducing a new caged queen? And upon removing the devise, I would suppose you have to go to the chamber below to kill the old queen, right?
If I want to use it for combining small colonies with new queens I like to keep, with stronger colonies... I guess you put the small one on top, wait (how many days???) before removing the doble screen.
>If using for requeening, here is my first question... For how long would one leave the double screen on, after introducing a new caged queen?
I guess I play things like this by ear. If the colony was calm in the first place and the bees seem to be accepting of the queen cage then I might just do this a couple of days. If not, I might wait three or four.
Basically the method is to take a couple of frames of emerging brood and a couple of frames of honey and pollen and young bees from the brood chamber below and put them above the double screen. Almost like you're doing a split. Put the queen in her cage in here and wait a day or two and then release the queen. Meanwhile when making the "split" is when I'd get rid of the old queen, or if you want to do what Axtman recommends, save her in a small nuc with some emerging brood so you can use her for emergencies.
>If I want to use it for combining small colonies with new queens I like to keep, with stronger colonies... I guess you put the small one on top, wait (how many days???) before removing the doble screen.
A couple of days is long enough for them to get used to each other's smell. I usually just do the newspaper combine, but if you give them a 2 days of smelling each other first you could skip the paper or use the paper for more insurance.
You can also nail them or screw them on as a ventilated top for moving bees without overheating them.
My favorite use for the double screen is for wintering a weak hive over a strong one. I haven't used them for splits, but they say you can.
You can buy them from Brushy Mt (cat #694) for $14.50 each, or make one from the plans in the plans section on Beesource.