In the years prior to the American Civil War existing organization of workers in the iron industry was established on the basis of independent local groups.
The first national convention was attended by 35 delegates, representing local iron molders organizations located throughout the Northeast and as far west as St.
[2] The Molders' Union initially took the form of a loose federation of already existing local organizations, each retaining almost complete autonomy.
[4] The organization grew rapidly during the years of the Civil War, with non-union journeymen joining in great numbers.
[6] In 1899, the union made an agreement with the National Founders' Association (which represented approximately 500 important employers in the industry) to arbitrate bargaining disputes.