MAKING YOUR OWN STUDY BILLS

The first step in designing a carving is gathering good reference material. Photographs, study skins and taxidermy mounted birds are useful, but have their limitations. I've seen really nicely executed waterfowl carvings ruined by undersized bills that the artist faithfully reproduced from measurements made of a mounted bird. Many people don't realize that bills and beaks start to dry and shrink soon after the bird has died - rapidly in the hot sun if you find a road killed bird, and drastically in freeze dried or older mounts.

Commercially made study bills are available, and most are good, but you may have difficulty locating the species you want or you may want to see the details of structures inside the open bill. It's very simple to make your own.

GETTING STARTED

For your own personal reference, a collection of study bills made from Dental Stone is quite adequate. The castings are durable and strong.

If you want to make multiple copies (if you are teaching a class, for example, and want to provide each student with a casting) you can use your Dental Stone cast as a "Master" to make a more durable latex or RTV mold for multiple resin castings.

I'm limiting instructions in this article to making molds and castings from the actual bird, using Dental Impression materials and Dental Stone for casts. These can be made very quickly at home or in the field. A list of suppliers will be provided at the end of this article.

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MOLD MATERIAL:

I use an Alginate Impression material. (Jeltrate or Surgident are two brand names.) This is the stuff you bite into at the dentist's office when you are being fitted for dentures. There are two types: Type I is FAST set and sets too quickly to be practical. Type II is NORMAL set and is easier to use.

This stuff is great for birds because it is not affected by blood or water, and does not stick to the feathers (which would ruin the bird for further reference purposes.)

CASTING MATERIAL:

I use dental plaster. It is very hard and picks up the smallest details. (I've been told you can also use #1 molding plaster, which is available from hardware stores.) DAMS & ENCLOSURES:

You'll need something to pour the Alginate mold material into. It needs to be big enough to allow at least a third to half-inch of Alginate material between the bird bill and the container. I use paper cups, small paper boxes or aluminum foil shaped around any convenient form, such as a pill bottle or the bottom of a soft drink can. The enclosure material should be flexible enough to be peeled away from the Alginate mold after it sets up. VIBRATOR:

Using a vibrator, held against the side of the Dam or Enclosure will "liquefy" the plaster. The plaster will then flow into all the crevices of the mold and air bubbles will be floated to the surface while the plaster is being poured into it. An inexpensive vibrator from the drug store works best, but you could try using the vibration from an orbital sander.

If you're working in the field, you can place the Alginate mold in a plastic bag (avoid squashing it) and wait until you get home to pour the plaster. It'll keep for a couple of hours if it doesn't dry out. Or pour the plaster in the field, tapping the mold with your fingers to try to work the plaster well down into the mold.

WATER:

If you're making up a "kit" for your car, a small leak-proof bottle can be carried with you. At home, I use ice water to slow down the setting speed of the Alginate.

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MAKING THE MOLD

POURING THE PLASTER

If the bill is long and pointed or hooked, I also try to encourage the plaster to fill the very tip of the bill by gently dipping a thin, soft paintbrush tip into the plaster (still holding the mold on the vibrator) and down to the tip of the bill. Don't damage the mold doing this, and wash the brush immediately or it'll be ruined when the plaster sets. If you don't do this you may find that a stubborn bubble of air remains at the tip of the bill. Another technique is to GENTLY squeeze the mold a little it as you hold it on the vibrator.

Let the plaster set-up and harden according to package instructions. The Dental Stone that I use takes about 10 minutes.

UNMOLDING THE CAST BILL

Jeltrate molds are usually good for only one casting. If it's a simple straight bill, and you can pull it out without damaging the mold, you may be able to make one or two more casts.

Unmold the straight bills by gently wiggling the mold material to loosen it, and pull the bill out. For larger or hooked bills, I recommend carefully cutting the Jeltrate away from the bill. Use a sharp knife, take your time and remove just a little at a time. Be careful not to cut into the bill or to cut off the bill tip.

Be gentle. The plaster has not yet reached its full strength and you don't want to snap the tip off.

DRYING THE CAST BILL

The plaster will be warm at first as the chemical reaction takes place. Then it will feel cool as the moisture evaporates. When it dries completely, use the flat back area to write the bird's species, sex, age (nestling, juvenile, adult) and any other information you desire - such as weight, length, etc.

SUPPLIERS AND REFERENCE MATERIAL

You can get the Alginate Impression Material and Dental Stone from the same place your dentist buys it. I order from:

Another source is:

Call and ask for their catalog. They also offer an excellent manual, "Make your Own," a how-to reference for making molds. The catalog is full of other wonderful goodies, such as highly detailed rubber lizards and frogs - great reference material.