Chuck, >I've a question related to the casting of metal sundials. > >Which metals expand the most with heating and by how much? >(I don't want the best behaved - I want the *worst* - metals that >expand the *most*). > >If I remember rightly, Tony Moss made reference to metal expansion >in an earlier e-mail. >
Of the common metals ZINC is the culprit. Every inch of length expands 0.0162 of an inch for every degree Fahrenheit of temperature rise. Then comes aluminium with 0.0128" Duralumin - an aluminium/copper alloy is a close third with 0.0125" Gunmetal (type of bronze) 0.0101" Fuller listing or metric equivalents on request. Many diecasting alloys of the sort once used for toy cars etc. are zinc based. They are heavy and take fine detail very well but will expand a lot when heated. Tony Moss
