Section 178.33-6 - 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.29 FR 18823, 12/29/1964, as amended by Order 71, 31 FR 9074, 7/1/1966. Redesignated at 32 FR 5606, 4/5/1967