if I understand your question, you are not asking about actual fiberglassing the outside of your hives with fiberglass cloth or some other composite structure, just painting them with the resin. Right? If so, I think it's a good idea.
epoxy is much easier to work with, doesn't stink and I think it would seal up the outside of your hives beautifully, they will last a long time in my opinion. Painting the exposed end grain on your boxes with epoxy resin will seal it up and protect it very well and probably extend its life.
Bix, you are correct, i just want to paint with the resin and have it soak into the wood to seal and protect.
not really interested in creating a layer of resin on top of the wood.
I'm not sure what type of resin we have here, it has the consistency and look of polyurethane, but a bit darker in colour. it does have a smell but i'm not sure if i would say it's overwhelming but you have to use it outside or well ventilated indoors. the hardener is a clear liquid like water.
If you don't paint it it will crack in a year.
affreux, i figure if i just use it to soak into the wood and not create a film on top of the wood, then cracking wont be much of a problem, on the other hand if it actually seals the wood fibres and i do paint more to creat a film on top, if it cracks then that may not be much of a problem.
Epoxy on wood is widely used to build boats.
If left unpainted it is recommended to use a coat of varnish every year or three for UV protection...but the epoxy will seal the wood VERY well.
Berengondo, this is my thinking also, but i'm not thinking to paint it after, just seal the wood to preserve.
I'm going to experiment with one box and see.
my main concern is, does the material will emit any toxic fumes or oils or such even after it has cured?