Original poster: Ian Macky <ian@xxxxxxxxx>
Original poster: "Lau, Gary" <Gary.Lau@xxxxxx> Many of the "rules of thumb" are not presently explained by any known (or at least simple) laws of physics, but simply reflect what has been found to work best - it's just the best we can do.
Nothing wrong with that! In that welding program I was in they told us many of the tables are based on empirical data and there's no theory backing it up-- it's just what was found to actually work. Experience is great stuff, no excuses necessary. --ian