Originally Posted by PNGento
I wanted to place a carbon monoxide/smoke detector on the outside wall above the bedroom window, but the screw acted like it was trying to bite into metal.
If you haven't hung the detector yet you must now have a mark on your wall where it felt like you were drilling into metal. Did it feel like metal when you first tried starting the screw? I mean was it only an 1/8th or 1/4 inch deep. If so take a 1/16 inch drill bit and see it there is an aluminum stud it there. You will punch through it really quick. Just don't drill deep. If there is metal in there you can mount to it with the correct sized pilot hole.
That would take care of the scar on your wall.
After re-reading your post. I don't understand...."outside wall". Your not putting a detector on the outside of your trailer are you.