An argument is strong when the premises support the conclusion. The strength of a chair is judged by its capacity to support the weight of someone sitting on it. By judging how well the parts are put together. By judging the quality of the parts.
Arguments consist of parts.
An argument can be analyzed by describing its parts and how they are related. The strength of an argument can be evaluated by juding how well the parts are put together and by judging the quality of the parts. Suppose that the parts are all of excellent quality, but they were assembled in a sloppy way. Perhaps needed parts are missing or the parts used don't really fit together. In either case, the strength of the chair will be diminished.