I have done a lot of sheet metal repair work with a 110 flux-core welder. I have the dubious honor of having gotten pretty good at it (at least as good as I feel I can be given the equipment).
It wouldn't be my first choice. Especially since you're asking this question, it makes me think that you're not especially familiar with the machine (or, possibly, welding in general). In that case, you're not likely to be happy with the results. Usually, .030 wire is the smallest you can findm which will work, but is not ideal for any kind of precision. And the clean up after using flux-core wire makes a true MIG a comparable bargain if you ever want the finished product to look nice once painted.
Just my $.02