bembel wrote:@inJapan: You will need something that holds everything in place and the clamps should apply some pressure to it. A vise shouldn't be needed this way.
Please let me know how it worked out.

.
Ok. So I gave it a try today.
I tried all sorts of plastics.
Now first I need to add... My picks are made from Bobby pins.
I came across a few problems.
When the plastic melts, then my pick falls through the melted plastic. So I end up with plastic on the top and my pick on the bottom. Then I tried melting the plastic in a big goopy ball, like the video, and shaping it around the pick. Actually worked out OK.
So I tried all sorts of plastics that I had lying around the house. Some worked and some didn't. Some just shrunk down in size and became super hard. Some melted and lost its shape all together. Some became brittle, some were all rubbery and soft.
I guess what I'm trying to say is, if you want to, play around with some plastics you have lying around at home and you'll come right..
As for myself, I prefer smaller handles. I just put one or two heat shrinking wire insulators and Im as happy as can be. You have more feeling of what your pick is going through during the job. It's more like fishing. One can feel each little nibble.
So, the plastic thing works. Depending on the type of plastic and heat, all you need is a few minutes to make a few handles. But I will not be doing it again.
Ps, I see what you meant about wanting to use clips during during the melting process. I tried it. The clip was too strong and when the plastic becomes hot, the clip down more bad than good. I lay a flat pice of metal over the plastic before melting in the oven, that stopped the plastic from curling up and deforming too much.