Ok, a year or so ago I was tinkering with modding some screened bottom boards on eight frame hives so I could use oil trays with them. Intheswamp's Simple Oil Tray (ISOT) was born. In case you would like to read the original thread so you have the background for this thread here a link to the original thread: http://forum.beemaster.com/index.php/topic,38714.0.html
The tray seemed to work pretty good, though the gap between the lip of the pan and the bottom surface of the bottom board was problematical. I tried a couple of things and none of them worked really well. The other day I decided to revisit the ISOT and see if I couldn't figure out how to get that gap just right. Mind you, I'm no carpenter, and basically used a handsaw, hammer, knife, a drill, and heavy scissors to do this. Nothing fancy, nothing furniture grade. :-DA note: I run all eight frame hives.
The screened bottom boards that I'm using were ordered from Rossman's in Georgia. They recently made a change to the back of their sbbs in that they added an extra trim piece to the back of the board so that the bottom edge of the back was flush with the bottom of the side runners. If you decide to order some from them for this mod ask them to leave that rear trim piece off.
Anyhow, here's what I have finally come up with...
This is the top view of the bottomboard. You can see the front section of flashing at the entrance. This is drilled with 5/32" holes. OJ Blount uses a stainless steel grid with 5/32" holes and states that it works great. A 5/32" hole is 3.97mm in diameter, almost a full millimeter smaller than what is called "small cell". A small hive beetle averages 3.25mm in width (they are longer than this, though) so they should easily pass through this size hole. If a 5/32" hole is laid over a #8 screen it will basically reach the covers but also "round out" the sides...creating a diagonal of the #8 mesh all around the perimeter...so if a beetle could have only gone through the #8 "at an angle" between corners it should be able to pass through the 5/32" hole at any approach/angle.
You can also see the right-triangle molding that I picked up at Home Depot (Lowes didn't have it). I only nail this in (no glue) as one day I might want to replace the screen or something. The Rossman boards have about an inch of flat area along the sides and back that I figured the beetles might land on if they're knocked down from above. I'm hoping that when they fall and hit the angle of the molding that they will bounce out into the mesh over the oil tray.
Here is a shot from above with the tray slid out.
The bottom. First thing I did was to nail and glue on a piece of 1x pressure treated boards to the bottom of each side rail of the hive...this lifted the hive up enough to hang the tray and leave a little extra wiggle room beneath the bottom board. The white pieces of wood used were some old molding that somebody threw away. Worked great for what I needed to use it for! ;) The two small piece towards the front of the bottom board are simply "stops" to stop the tray at the correct position...2 frame nails and some glue. The two long pieces of molding are runners that the lip of the oil trays slide on.
Close up of the bottom sideof the porch area with the pan pulled back a bit.
Bottom side with pan removed.
Close-up of one corner of the back of the bottom board where the pan slips in. You can see the gap between tray and bottom board...I measured 1/8" so it will take a *really* small, small cell bee to get in the oil. ;) I ended up using a piece of 1/4" flat molding as a spacer. I laid the flat molding down and pushed up against the side rails, I then pressed the quarter-round molding down against that and glued and nailed the quarter round molding to the side rails. Once nailed good I removed the flat molding that I was using for a spacer. This worked very well in leaving room for the tray to slide in. I will be painting the bottom boards but will probably only use some primer in the slot area.
At last, but not least. A "head-on" shot of the front porch of a bottom board that is using a slotted piece of flashing for the area at the entrance, rather than the drilled 5/32" holes. The idea is that the beetles run in, get harrassed by bees and look for a dark spot to dive into...the raised lip and the downward turned lip helps guide them into the safety<g> of the dark slotted area.
This batch I made three with holes and one with slots. They will be going beneath four nucs I hope to start after I harvest my honest.
Well, that's about it, just thought I'd share it with you...