John, In the report of your highly successful tests you describe:
"We have about 25 hops on this set of jet vanes now, and they have taken on an interesting coloration pattern:" These colors are not only interesting but also useful and can give some clues. By observing the tempering or annealing colors the max temperature the parts were heated up can be determined in a rel. narrow temperature range from about 220�C to 320�C (428�F to 608�F) The parts have to be bright before being heated. So if there are weldments like the joint between the axle and the vane the discolorations have to be removed. The approximate temperature scale is as follows: pale straw yellow 220�C / 428�F dark straw yellow 230�C / 446�F brown yellow 255�C / 491�F yellow tinged with purple 265�C / 509�F purple 277�C / 531�F pale blue 288�C / 550�F cornflower blue 293�C / 559�F blue black 316�C / 600�F grey/black >320�C />608�F Hans Ulrich Ammann mailto:[EMAIL PROTECTED] _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
