A fixture is provided for holding sheets having complex shapes during heat treating. The fixture includes a base having a central opening and defining a peripheral foundation. A support structure extends inwardly and upwardly from the base and across the central opening. The support structure includes first axial and traverse openings extending there through. A sheet engagement structure is secured to the support structure and includes second axial openings extending there through. The sheet engagement structure has a peripheral section and at least one connecting leg extending between portions of the peripheral section. A sheet securing ring is removably secured to the sheet engagement structure for slidingly securing a sheet between the sheet securing ring and the sheet engagement structure. The central opening, first axial and traverse openings and second axial openings cooperating to create a uniform and accelerated flow of fluid through the fixture.