The missing piece of information regarding high lead pipes is that the metal is tensioned by hammering rendering it stiff enough to stand for hundreds of years if otherwise unmolested. I built an organ in 1979 with hammered metal pipes made of 98% lead. The other 2% was tin and antimony.

The pipes are as stright today as the day they were made.

One argument in favor of high lead pipes is that they give an unmistakable tonal bloom which cannot be obtained with other metals. It will, of course, not take a high polish. I was hoping that my pipes would oxidize black in time, but there is insufficient airborne polution in the little country church in which the organ is located to accomplish that.