I keep a half inch thick sheet of rubber on my bench to use as a
backup for repousse. I made a Orchid post about this back in 2000.
Here is the link to my original post if you would like details:
I will say that before I found my rubber sheet I used lead blocks
which I made by pouring molten into cardboard check boxes that were
reinforced with masking tape. Of course, I did this outside in good
ventilation. I used the lead blocks inside a zip lock plastic bag so
that my metal and my hands never touched the lead. The plastic bags
also contained the lead dust that spalls off during use. There was
always a lot of lead residue coating the inside of the zip lock bag
when I changed to a new one so it was probably good for my safety
that I found the rubber backing that I now use.
There are several examples of my repousse metalwork on my blogspot
below.
David Luck
http://www.davidluckjewelry.com