An improved method is disclosed for the fusing, joining or seaming of cellulosic materials. The method utilizes a hydroxide solution of selected organometallic compounds or metal oxides to rapidly crosslink opposing, overlapping cellulosic surfaces to provide secure seams. In particular, the invention is directed to the production, either on-line or off-line, of tubular cellulosic casings for the manufacture of sausages and sausage-like products. The seams according to this invention have such high shear strength that extremely narrow bond widths are possible. The narrowness of the bond site eliminates or minimizes striping or discoloration of the finished product.