542 



MARINE PRODUCTS OF COMMERCE 



Removal of the Skin. On board the vessel or on arrival at the dock the fish are 

 at once skinned. This is done by cutting down the back from head to tail; by 

 means of short strokes of the knife the skin is worked ofiF the side and by a 

 rolling motion is separated from the belly. This method of skinning gives a uniform 

 pattern of a V-shaped design which is a solid skin, except for the opening at the 



Heod flop--- •- 



Back split---»- 



Trim along 



this line 



Trim here on 

 Leopard and^^ 

 Sawfish only 



This piece with 

 keels is of no volue 



-•--Head flap 



Chin flop 



Hole left by 

 anal fin 



Keels or boney port 

 only on Leopard and 

 Sawfish species 



Fig. 25-2. Hide after being 

 removed from carcass. 



pectoral fins. At some stations the skin is stripped off by using a tripod and utilizing 

 the weight of the fish as an aid in separating the pelt. The flayed skin is next 

 worked with a sharp knife over a rounded beam to remove the adhering flesh. 

 When properly cleaned the skins are given a liberal coat of salt and placed in 

 piles to cure. When the cure is complete, the skins are rolled into bundles for 

 shipment to the tannery. 



Tanning Operations. As the skins arrive at the tannery, they are placed in pits 

 containing fresh water, which serves to soften them and remove the salt. They 

 are then transferred to lime liquor in order to open the fiber bundles and remove 

 the cementing material, the same methods being followed as for animal skins. 

 As in the handling of hides they are fleshed on the machine and then bated to 

 remove the excess of lime and open up the stock. 



Vegetable Tannage. If the skins are to receive a vegetable tannage, they are 

 placed in a paddle vat containing a solution of tanning extract. The strength of 

 the hquor influences the resulting product, the same precautions being observed 

 as in the tanning of animal hides. When the skins have absorbed the required 

 amount of tannin, they are removed from the paddle vat and washed. At this 

 stage of the process the shagreen is removed by milling with an acid solution, 

 the skins then being well washed to remove the excess of acid. They are finally 

 fat-liquored to prevent hardening and are hung up to dry. 



Finishing Operations. The dried skins are dampened back with water and 

 ether, colored with dyes or pigment-finished. The final finishing is done on a roll- 



