Canopy lid wood

[deepseadan]

I just built a canopy out of pine. I stained it and put 3 coats of polyurethane on it. It was for a 20 gallon tank. My problem is that the top lid has warped (within) three days of use. I'm not sure if it's because I used real pine wood and not plywood. I also don't know if it's the heat from the lights or moisture from the tank. Anyone have any experience building canopies.

 

[ozorowsky]

I just built a canopy out of pine. I stained it and put 3 coats of polyurethane on it. It was for a 20 gallon tank. My problem is that the top lid has warped (within) three days of use. I'm not sure if it's because I used real pine wood and not plywood. I also don't know if it's the heat from the lights or moisture from the tank. Anyone have any experience building canopies.

I built one; but mine slightly warped as well. I'm going to follow this thread.