how do I make a mould of my arm and cast it in clear resin ?

Here is a link for making a mould of a hand in something called 'alginate' (which looks like a cold-pour skin-safe version of vinamould.

The video shows them pouring resin in.

The results look pretty good though, to get the arm in too, presumably you'd need a longer receptacle.

In the old days, you would have needed to make a two-part cast with plaster.

definite you are able to, inspect "Por-a-mould" on Dick Blick's internet site. additionally some close by paintings factors shops carry the two silicon mould kits & sparkling resins. anticipate a great mess, yet you're able to do it.

Why don't you visit http://www.craftster.org/ they have sections on ALL sorts of art and crafts....read the sections and pick the one you think is most likely to have people in it who will know about this...such as sculpting...you can ask questions and they have great members who are very helpful and friendly.