aluminum 1911 80% finished frames are

very hard to get, and the quality of the machining typically sucks on them, too. They can be MADE to work, but you'd better be both one helluva smith, AND a good welder, cause you are very likely to have to replace metal that they screwed up and removed. The mag release hole is likely to be oversized and/or misplaced, the holes thru the frame are likely to be crooked, etc.