Materials:
5 lbs. prosthetic grade cream (alginate)
2 boxes of 4" wide extra fast set plaster bandages
cotton batting
4-2 gallon buckets
2- 8' 1x2"s cut 1 in half and the other in fourths
50 lbs of hydrocal
8 yards of burlap cut into 6x9" strips
Vaseline and hand lotion
Two cheap 5 quart sauce pans
a dual electric hotplate or electric stove
15 lbs Van-Aken Modeling clay
12 lbs Roma Plastilina
OR 24 lbs Chavant NSP Medium clay (my favorite!)
50 lbs of white clay em-210
5 gallons of slip cast latex
1 gallon kit of poly foam/ Or fiber glass
Proline tints
Badger airbrush paints
99% alcohol
Airbrush & compressor
Crazy glue
An assistant!

The procedure:

Trim body hair to 1/4".  Unroll and fold the plaster bandage into 24' lengths that are 4 layers thick, we will call this a slab.  Make 14 each of 24" slabs, make 10 each of 10" slabs and set these aside.  Get two pieces of the 1"x2" (4' length) and two pieces of the 1"x2" (2' lengths).  Weigh out your prosthetic grade cream into two equal batches; weigh out the water into two separate buckets. Follow directions for ratios.  It is usually about 25 grams of alginate to 100 grams of water.
Keep your water around 80 degrees as warmer water will speed up the set time while colder water will slow it down.  The water should not be too cold or your victim will get goose bumps which is not the desired effect.
Apply a heavy coat of Vaseline to armpit hair and a light coat of hand cream to body hair. Alginate does not stick to skin.  Lay you victim on a sheet of plastic.
Mix 1 batch of  alginate into 1 bucket of water and stir for about 1 minute. Rub it onto the chest and smear it in quickly for good coverage ensuring that you have applied it evenly on the sides.  At the 3 minutes mark, dump the rest on and letting the assistant work the drips back up.
Immediately mix the 2nd batch and apply. You want the alginate to be a minimum of 1/4" thick all over but allow the alginate be thicker on the sides and around shoulders, etc. These areas are undercuts and you want them to "fill in" around the curves.  Before the alginate sets completely you want to press the cotton batting into the alginate and then peel it up leaving fibers imbedded in the alginate.  This will help the plaster bandage bond to the alginate and keep proper registration.
Once it has set; dunk a slab of bandage into a bucket of hot water, lift it out,  rub it onto itself and squeegee it between you fingers.  Lay this lengthwise down the middle of the torso and rub it down, get out any trapped air. Continue on either side overlapping about a half an inch. Once you have cover it lengthwise, reinforce with some 10" strips horizontally. Lay the 48" 1x2" lengthwise from the shoulder to the pelvis and secure with bandage.
Repeat on the other side. Lay the 24" 1x2" from shoulder to shoulder and the other across the waist, secure with bandage.
Let the bandage set, it should heat up and then cool down.  Trim excess alginate and have your victim take some deep breaths and flex.  You and your assistant can then loosen and  remove the cast. Be careful in the removal process as the alginate rips easy.  Don't let the victim help or sit up during this time!
Once the cast is off flip it over onto the wood frame.  Trim excess.  Glue the sides to the bandage with crazy glue and at that time you can fix any rips with the crazy glue.  This is best done before you start the alginate unless you have a second assistant. Cut your clay into small blocks. If you are using the Van-Aken and roma it is a 50%/50% mix. melt it slowly and be careful not burn it, stir often.
Reinforce the sides of the plaster bandage with Hydrocal and burlap.  Wipe off excess moisture from the alginate.  Pour one pot of melted clay into the mold and quickly brush it into the detail.  Pour the second pot and repeat the process. You want an even thickness all over and thicker on the sides.  Remember those damn undercuts!  As the clay cools it will thicken.
After the clay has firmed up, mix up a batch of hydrocal and dip some burlap
strips.  Back up the clay with the burlap and plaster (you want it 2 to 3 layers thick).  Not too much though keeping in mind that you will have to break this out later.
Cut some 1x2" to make  horizontal reinforcement/handles.  Secure them with burlap and plaster. Let this sit over night.
Carefully flip the mold over.  Remove the plaster bandage mother mold and discard.  Even more carefully peel off the alginate and ...VIOLA!  You have an exact (hopefully) copy of your victim's torso in clay. You can resculpt any defects or add new ones!