Sealing the interior of a Dadant top feeder - what to use?
After experimenting with Brushy Mountain and Dadant brands, I bought 9 more Dadant top feeders for my backyard apiary because fewer bees drowned in the Dadant unit than the Brushy Mountain unit.
Although I did not have this problem with the first Dadant unit I experimented with, many of the subsequent 9 units that I bought leaked. The Dadant wood is cypress and is unsealed. After a week of being filled with syrup, the side panels of the Dadant unit absorb enough liquid to warp and pull away from each other and cause leaks. The clear sealer Dadant smeared into the corners of each feeder was not able to maintain a seal in the face of such warpage. Interestingly, the Brushy Mountain unit had the interior surfaces waterproofed with a clear sealant.
Is there some product I can paint/spray onto the interior wood surfaces to seal it and stop the warpage and which won't leach unsafe chemical into the syrup?
Has anyone else experienced this warpage/leakage problem with Dadant top feeders and found an easy and cheap solution?
(4th year, Zone 5b, 11/12 hives survived W'14)