Best way to use Canadian clearer board?

[Tomo]

Hi. At the start of the year I purchased some used kit, amongst which is a Canadian clearer board which the old beek said he had used successfully for many years. It is about 3 inches deep with 4 holes on which are "witches hat" type escapes. These escapes are level with the bottom of the eek like space. My question is: do I place this directly above the next super/BB or does it need an eek below it to work? It just seems that surely the bees can walk back up through the holes? Thanks.

 

[Erichalfbee]

You put it under the super to be cleared but the best thing to do with it is to remove the cone escapes, block off the central hole and fit half rhombus escapes over the holes in the corners.

 

[jenkinsbrynmair]

You put it under the super to be cleared but the best thing to do with it is to remove the cone escapes, block off the central hole and fit half rhombus escapes over the holes in the corners.

Much less faff

 

[Tomo]

Should I just use the rhombus types under a normal crown board? I imagine the bees will fill the void with comb otherwise?

 

[BeeJayBee]

They shouldn't have time to fill it with comb, it's only meant to be on for a day at most. I've found a framed rhombus will clear supers in a couple of hours, I put an super beneath it so the bees have somewhere to go.

 

[tractorjohn]

 

[Gilberdyke John]

They shouldn't have time to fill it with comb, it's only meant to be on for a day at most. I've found a framed rhombus will clear supers in a couple of hours, I put an super beneath it so the bees have somewhere to go.

I use a rhombus clearer I made up by cutting a 50mm hole in a crown board, fitting the plastic escape and attaching to a 90mm eke to provide space for the cleared bees. It cleared two supers together in 24 hours. I haven't looked in with shorter periods of use but 24 hours is a period I am happy with.
I agree longer periods would invite random comb drawing in the clearer.