Reading various questions and answers around here, I've heard a lot of people say you can tell the quality of the bicycle by looking at the welds. How do I know what a good weld looks like as opposed to a bad weld. In this answer its stated that good bikes have smoother welds. However, when looking at my bike, the welds don't really appear to be smooth at all, even though I know it is a high quality bike. What should I look for when looking at the welds of a bike? Pictures would be greatly appreciated.
I found This site about welding to be somewhat helpful. There's an image near the bottom comparing a good weld to a bad weld on aluminum. The good weld is actually the one that isn't smooth. The type of weld used differs on the type of material used (steel vs aluminum). A lot of the information on this site talks about coloring, so you can tell if they went too slow and burned the material, but this would often be covered up by the paint on a bike.