Re: [beemonitoring] Painting making bowls fragile
I found that cups do tend to get brittle after a couple of years use, particularly the white ones. I also had trouble with spray paint dissolving the cup plastic. I have used the Krylon white plastic fusion paint with little problem. However, after spraying the fluorescent yellow and blue (Krylon or Ace brand; blue easier to find at Ace hardware), some of the cup bottoms would just pop out as though cleanly cut with a knife. The 3.25oz Solo cups have a small depression around the inside bottom rim, and pooling of the paint there probably caused the problem. So I fill that depression with a water based paint (like the ones Sam recommends in the Handy Bee Manual - although any latex paint would probably do) or a water based or silicon glue, before spray-painting. I suppose that priming with the white fusion paint might work also, but I prefer having the color show through the sides (I do not know if it makes a difference to the bees - something for someone to test) - also one reason I prefer the easier-to-obtain translucent cups than the white ones.
The main problem I found with the spray paint is blowing the cups away, requiring holding each one down with a stick or something (or a hand if you don’t mind the blue and yellow combination turning it green). So I made a series of holes with a 2 3/4 inch hole saw on a power drill in a small sheet of Lauan plywood (or any thin plywood)(photo attached). That hole saw size is just right to hold the 3.25 oz cups by their top rim. Strips of wood, about 1 ½ in tall, are nailed at the ends to make room for the cups to hang. I made four of these 10-hole holders, which makes short work getting the cups painted.
Please note, as in the photo, that the full page BP newspaper ads are good to use under the cup holder when spraying - although I can think of even more appropriate ways to use the ads.
University of Florida
I use the 12 oz stadium cup method here in Arizona. I use the Krylon plastic primer first then spray the fluorescent yellow and blue on the cups. I set the traps for one week per month. I don't leave them out during the interim period. So far except for paint peeling from a few spots that I obviously missed with the primer my cups are still as strong as before. Another advantage to the stadium cups is that they of course are stackable and very sturdy. I can just stack them and throw them in a box in the truck as I check trap sets. The Handy Bee Manual has a write-up of this method if your are interested.