OPCMIA – Strength in Numbers

In 1864, recognizing that there is strength in numbers, the National Plasterer’s Union or the National Plasterer’s Organization began to unify the various crafts unions representing our trade. This new organization, the Building Trades Union, attempted to lay the foundations for standard wages, working conditions, regulated training for it’s members, a travelling card system, and exclusion for those unqualified for membership.

After seeing Union brothers suffer through many years of excessively long work days, in 1882 this new Union successfully established the eight-hour work day. Along with this success came the Union pledge of avoiding any “unnecessary strikes”. In 1887, we welcomed our Canadian brothers into membership and in 1914 renamed our Union to Operative Plasterers’ and Cement Finishers’ International Association.  The following year the Union reached an agreement with the United Brotherhood of Cement Workers who strengthened our numbers by joining our membership.

Our trade took a huge leap forward in 1946; the Union worked with the Associated General Contractors and the Contracting Plasterers’ International Association to establish national apprentice training standards. Recognizing that member skills were moving beyond just finishing cement, the name was changed to the Operative Plasterers’ and Cement Masons International Association (OPCMIA).

LOCAL 633 – Strength in Training

A small group of craftsmen, holding meetings in a garage, established Local Union 633 in 1922. In 1998 Local 633 purchased the 14,000 square foot training center that sits on 2.5 acres of land in New Brighton Minnesota. The Joint Apprentice Training Committee for Local 633, more commonly known as JATC Local 633, uses this space for training and re-certification.

The JATC Local 633 training program has evolved into a nationally recognized leader in the training of superior craftsmen and women. Our Contractors are willing to invest in the future of each apprentice by supporting them through every phase of the training program. Certification includes extensive time at the training center and also several hours of on-the-job training next to high-quality Journeymen. Our apprentices also get many opportunities to work on community service projects.

JATC Local 633 provides a thorough foundation for a successful career upon completion of the Apprentice Program. Our Union Contractors are actively recruited. Our employers seek masons, plasterers and shophands of all nationalities and ethnic backgrounds.


To train our members to the highest of standards and enable them to be exemplary craftsmen and citizens for the benefit of their livelihood, the Union, the industry and the United States.