I've never had a problem with a wooden frame feeder with float - but did note when I used a giant, (green plastic) rapid feeder a similar problem - thebees couldn't get out of the syrup up the ribbed cones and I subsequently gave the cones a good sanding to roughen the surface but - not used it since. The giant feeder does seem to accommodate two national super honey combs so useful to feed frames of honey back and not a complete waste of money - but I'll stick to the smaller contact feeders and make more trips!!
