I'm brand new here. This forum was recommended by a friend. I'm an avid DIY-er but finishes are not my specialty.

The problem:
I built a steam radiator cover (out of red oak) for my 8mth old son's room (turned out great). The minwax oil based fast drying semigloss polyurethane has not dried properly and is giving off a smell as the radiator heats up.. I'm concerned about safety (fumes) so I have removed the cover until I can fix the problem.

The finishing process:
We live in a small 2 bed APT in NYC, so I have less than ideal circumstances for woodworking.

For the first coat I applied the polyurethane directly to the (sanded/wiped clean) surface of the wood. *it it possible that the can was not stirred well enough. * the first coat was possibly thick but had no runs. I sat outside my apt in the sun waiting for the finish to off-gas. After an hour I brought it inside to cure.

After 4 hours the finish seemed cured (the can recommends 3-4hrs). I sanded with 220 and wiped clean with a slightly damp cloth.

For the second coat (around 9pm) I had to change location, so I applied the finish standing inside our apt with the project sitting outside on the fire escape (on a cardboard box to catch drips). It was cold - about 50 degrees. I left it out there to off-gas for an hour, then brought it inside to cute overnight. *Again the can was possibly not stirred well enough.

The next day everything seemed fine other than a slight oily film (like the project had the tiniest film of cooking oil over it). I figured it would harden with heat and time, so I attached the aluminum mesh and installed it.... And now we have the problem.

Thoughts, guys? I'd love to avoid sanding this whole thing back to bare wood (as it will be by hand on my kitchen floor).