Section 178.33a-6 - Manufacture(a) By appliances and methods that will assure uniformity of completed containers; dirt and scale to be removed as necessary; no defect acceptable that is likely to weaken the finished container appreciably; reasonably smooth and uniform surface finish required.(b) Seams when used must be as follows: (1) Circumferential seams. By welding, swedging, brazing, soldering, or double seaming.(2) Side seams. By welding, brazing or soldering.(c) Ends. The ends shall be of pressure design.Order 71, 31 FR 9074, July 1, 1966. Redesignated at 32 FR 5606, Apr. 5, 1967