The AR is more or less an assembly, you don't need any kind of metal working experance. Take a look at the lower assembly procedure.
The Range Bag
But the AK takes a little bit more than the AR, here is a few videos of AK building.
http://www.youtube.com/user/BuildyourownAK#g/uI have done both ARs are real accurate, but the AKs are a lot more fun to build & a lot more of fun when you get it done.