The simplest way to do that is probably using thin plastic food wrap (aka cling film) and clear packaging tape (2"/5cm wide).  You can buy both for cheap at the dollar stores.

Cover the model arm with the plastic wrap, cut in strips -- just wrap it around the arm, and the hand. If you want finger detail, cut into narrow strips and wrap each finger individually. Secure the ends with small pieces of tape if the film isn't sticking to itself very well.

Next, wrap the plastic-covered arm with the tape, overlapping all the edges. Cutting it in half lengthwise should give you a smoother finish than using it full width. Try to keep it as smooth as you can.

When you think you've got it right, use a tape cutter to cut CAREFULLY one slit down the back of the arm, open just enough to remove the human arm, then tape the the cut back together.

Cover with papier mache (strip method is best for strength in this situation).

For some photos, see Here's How to Make a Human Tape Sculpture at Instructables:  http://www.instructables.com/id/How-to- … /?ALLSTEPS

CAUTION: If you want to use this technique with a human head DON'T FORGET to leave the nostrils open!

For some other nice results, google "tape sculptures"

Sue

CatPerson thank you for the help. Sounds like a great solution.

dopaiper, Durga is the costume being made. Or a literary version featured in a fictional book series.
Thank you for your advice.