When the skin is ready to apply, coat this plaster cast with some nonporous modelling material. A mixture of thin liquid glue and whiting is good for this. Some paper pulp is put inside the head and at the junction of body and fins. Shape from the outside with the fingers.
A piece of wood should have been placed in the back of the plaster cast when making same, in order to fasten to a panel by screws from the back. Paint the wood with melted paraffin before putting in the wet plaster or it may swell and subsequently shrink enough to crack the cast. By either of the preceding methods the entire fish can be mounted if desired.
The opening cut should be made from head to tail along the lower edge of the body in most scale fish and will require some neat modelling to hide as both sides are to be on exhibition.
Entire fish are usually supported by metal standards rising from a wooden base. Such standards are preferably of brass, threaded and fitted with nuts and rosettes at both ends. Two nuts at the lower end clamp the base and with the upper end inserted in the back board, the upper nut will adjust the fish at the right heighth. The rosettes cover the nuts and add a finished appearance.
Especially adapted to tarpon and other ponderous fish are medallions mounted on paper. To do this a half mould is made as described, the skin removed, cleaned, poisoned and replaced in the mould. Then it is backed up with numerous layers of soft paper, well pasted and pressed in with the hands. Let these layers of paper overlap the mould at least as much as the margin of skin left on the back.
When a sufficient thickness is attained fill the hollow form loosely with crumpled paper or excelsior and fit in place a back board of light wood. Nail through the margin of skin and paper into the edges of this. If a number of large holes were made in the back board it will expedite the drying out.
When partly dry, remove from the mould, painting and finishing as before when completely dry. By this means the contour of large fish is absolutely reproduced and the finished work is extremely light and durable.
Many of the smooth skinned fishes are impossible to mount satisfactorily, a cast is the best we can do for them.
When using a living fish as a guide in painting, it may be confined in an aquarium and by sliding a wire screen partition, be kept just before the artist's eye.