Fiberglass resin may seal a feeder very well, but how toxic is it to your bees and more important, how much is in there honey?
If a feeder is well-made with food-grade, water-resistant glue, why is it necessary to coat the entire inside of the feeder?
as far as I have tested fiberglass reson in my 5 years using it, I have found no contamination to the bees or honey or any by-product from the hives when using it alone without any coloring or fiberglass mat. When studying it I have found on the MSDS lable that when cured it is almost sterile.
just South of Lansing Michigan
The reason I use it is because I must be a poor carpenter as my feeders seem to develope leaks thrugh the years. Water proof glue? If you read the labels most glues that say waterproof aren't. Just water resistant. Also what if your wood warps? are you just going to throw it out?
The only waterproof glue, that actually seems to be waterproof, that I know of is Gorilla glue. I know its a polyurethane based glue, and it works very well. I have no long term time tested feeders from it yet, but so far so good. I put two coats of polyurethane on my feeders too though.
I have used Gorilla Glue on hive parts and frames for a few years with no noticed ill effects.