Plaster casts make a permanent record of leaves, ferns, animal tracks, seed pods, seeds, and so forth. Casts may he used in such articles as dishes, trays, and so forth, or may be made into plaques for wall decoration. A series of plaques showing interesting nature finds of the campsite might be a frieze around the dining hall or camp house.
Materials needed: plaster of paris; plasticene or modeling clay; thin cardboard (file folders); wire; coloring, if desired.
1. On newspaper, roll out a piece of plasticene or clay to flat pad larger than the desired object, with dowel, roller, or heel of hand.
2. Place leaf on clay pad, and impress it into clay with fingers (Fig. XV-4). Remove carefully.
3. Make a collar of a 2" strip of cardboard, and press around the imprint of the leaf, overlapping ends and joining with paper clips (Fig. XV-4).
4. Mix plaster of paris: put enough water in can to fill the mold to a depth of 3/4". Put in plaster until it forms a mound and comes to the surface. Stir gently so there are no lumps and the mixture is the consistency of heavy cream.
5. Pour mixture into mold slowly and carefully, so there will be no air bubbles.
6. Let plaster set, then remove collar and cast from mold.
7. Sandpaper edges, paint in colors, and shellac as desired.
8. If the cast is to be hung as a plaque, put small loop of wire in plaster in proper place when the plaster is partially set.
9. Plaster may be colored while liquid with poster paint.
If tracks are in mud or firm soil, make a collar around the track by pressing cardboard or tin strip into soil building a wall of soil around the cardboard collar, if necessary. Let it harden before pouring cast mixture into mold. From there:
1. Shake talcum powder into track.
2. Mix plaster of paris, and pour carefully as above.
3. Let plaster set, remove collar, and take cast from mold. This makes a "positive" mold, that is, the track will be raised.
4. To get a cast like the track in the ground, it is necessary to make a "negative" mold. (If these steps are used, it is wise to color the plaster for the positive mold lightly with a little poster paint, so the two parts may be easily distinguished.)
5. Coat the positive cast generously with vaseline.
6. Make a collar of cardboard around the positive mold, and make a wall of clay or plasticene outside the collar, to hold it firmly in place.
7. Mix plaster and pour into mold. Let plaster set.
8. Place wire loop for hanging, if desired, when plaster is partially set.
9. Remove collar, and separate the cast from the mold (Fig. XV-5).
Cast from mushroom or similar round object: making plaster models of mushrooms (or similar objects) will be an interesting project, one that will help in learning to identify them. Using modeling wax, make a copy of the mushroom. Then'make a plaster cast of the model. Coat the model with vaseline, and pour liquid plaster over it in a thin coat. Repeat when this plaster is hard. When the plaster is about 1/4" thick, cut through the plaster all around, so that the mold can be removed in two pieces (do this carefully). Take one half off, then lift out the model. Line the cast with vaseline, and pour liquid plaster in both sides; let set a little, then put both sides together and hold them tight with rubber bands. Let harden, then take the cast away. The model will need sanding and decorating to look like the original (see Chap. IV).
When such trees as white birch are already cut and down for some other purpose, it may be possible to use the bark to make boxes, baskets, and similar objects. Many articles can be made from birch or other supple bark because they can be cut and stitched, using leatherwork techniques (see Chap. V).
Great care should be taken to practice good conservation in the use of bark, and campers should have it impressed upon them that cutting bark from a live tree is not only injurious to the tree but also leaves it unsightly. For this reason, many camps discourage bark crafts. It is possible, however, to train campers to have respect for living trees, and as part of the nature program it is wise to help them know what they can use from the woods and what precautions they must take as good outdoor citizens. Sawmills that handle logs of birch and similar thin-barked trees may be willing to save pieces of bark for campers to use.
Bark should be soaked in hot water before using so that it will not crack. For baskets, boxes, drinking cups, carrying cases, picture frames, make paper patterns and staple the pieces together (see Chap. V). Punch holes with awl or spring punch, and lace with leather, raffia, or similar material, or stitch with large needle and string. Strengthen tops of baskets and boxes with a green shoot, overcast around top (Fig. XV-6).