Footprints are the most common form of evidence to support the existence of Bigfoot. When a footprint is found, a plaster cast of the print is often taken. Many casts have been looked at by professionals and are said to contain dermal ridges. Dermal ridges are similar to fingerprints and all known primates have them. The dermal ridges found on many prints don't appear to belong to any known primate or any other type of known animal. The majority of the casts taken look like they are too complex to be hoaxed and therefore could be linked to an unknown animal. When hunting for this creature, you should always take a picture of the print first, then take a plaster cast.
When you find a track, of Bigfoot or any other animal the first thing you want to do is secure the site. This means making sure that you, to the best of your abilities make sure that no other people or animals can disturb the track itself. Taking a cast takes a little time so it is possible for the site to be disturbed during the process if not careful.
If there is loose debris in the track itself you can freely remove it from the track before continuing. If the track has debris that has been compressed into the track you should not attempt to remove it from the track, because it will damage the track and your cast will be flawed.
What do you need to create a cast?
Dental Stone or Plaster of Paris, a mixing bowl, water, a cardboard strip, and a paper clip. Plaster of Paris is not recommended to make a cast due to its structural problems. Plaster of Paris tends to crumble and degrade at a much faster rate than Dental Stone. The cardboard strip is to build a retaining wall around the track as a form for the casting material. This produces a thinker cast and makes it more stable and less likely to crack. Dental Stone does not need to be as thick as Plaster of Paris for the same durability.
How to cast a footprint
Before doing anything document the track with a photograph and a ruler for scale. Then you can begin to take your cast.
Use the thin cardboard strip to build your form around the track. Overlap the two ends slightly and secure it with a paperclip or strong tape. If possible press the cardboard form slightly into the soil around the track. Be careful not to disturb the track itself. This makes sure the casting material will not run under the form.
Mix the casting material. You should use approximately 2 parts plaster to 1 part water. So, if you use two cups of casting material, you should use only one cup of water to mix with it. In general your mixture should be like pancake batter. You should add the plaster to the water and mix in as you pour. The casting material actually begins to set as soon as water is added so you must work somewhat quickly at this point. You should stir the mixture for about 4 to 5 minutes making sure that all lumps have been removed. It will take about 5 lbs. of plaster per foot.
Pouring the cast. After you are done mixing the mixture you should tap the container with the casting material in it on the ground or other hard surface. This helps remove any air that may be trapped in the mixture. You will actually see the air bubbles coming to the top. The more air you get out the mixture the better the cast will turn out. After getting the air out of the mixture you can begin pouring the mixture into your form around the track. You want to avoid pouring the mixture directly onto the track because it will damage the print. Pour the mixture into the form on the ground next to the track. The mixture should run freely across the track and fill the form.
Drying the cast. Let the track set for about 30 minutes. Letting the track set longer will allow for a potentially better cast. As the cast dries it will start to turn a duller less glossy white color. After about 30 minutes to an hour you can try tapping your knuckle on the top of the cast. If it makes a ceramic type sound it is safe to pick up. If the cast is still a little moist or hollow sounding let it sit for more time and try later. It may take as long as two hours for the cast to be dry enough.
Lifting the cast. To lift the cast you should lift it from opposite edges from beneath the cast itself. If the cast is in mud or some other soft ground you might need to dig a little under the cast. Never try and pry the cast out of the ground because it will likely break the cast. After the cast has been lifted you should not attempt to clean or paint it for several days. You should also not store it in a sealed container such as plastic. The cast still needs to let excess water escape and the best wrapping materials are clean papers. If you use Plaster of Paris do not scrub the cast to clean off dirt, this will effectively sand down any fine details the cast had. Dental stone is far stronger and easier to clean up. It is best to put the cast in a padded box to transport it out of the woods. Do not handle the cast for at least a week.