The story of Cub YellowThis question comes up from time to time on the Cub Builders list, and most recently was given this answer by Magnus Lord, who notes that "the info comes, as usual, from Clyde Smith Jr and the Cub Clues Magazine."
Piper originally used nitrate dope for the J3. This is the darker, more orange shade that Piper called "Lock Haven Yellow". Some time after the war, when the supply of nitrate dope was dwindling, bids went out from Piper for a paint manufacturer to come up with a pigmented yellow butyrate dope that would as closely match the nitrate shade as possible.
None of the companies could match the Lock Haven Yellow exactly, but Randolph was the closest and thus was awarded the contract. This butyrate yellow was a little brighter and more a pure yellow and though Piper continued to refer to it as Lock Haven Yellow, Randolph dubbed it "Piper Cub J-3 Yellow".
So, all J3s up until the change of dope during 1946 was painted with the darker shade which Randolph refers to as "Lock Haven Yellow" (#M-9521), while the butyrate doped J3s and ALL PA-11, 15, 17, 18 and PA-20/22 aircraft were finished with the light butyrate, Randolph's "Piper Cub J-3 Yellow" (#F-6285).
A nice detail: After changing to butyrate dope, Piper couldn't use dope for the boot cowl. The boot cowl had to be painted with enamel, and that is why the butyrate doped J3s (especially from Ponca City, Oklahoma) had a shorter black lightning bolt, ending (starting) behind the boot cowl.