gift for son's teacher-foot tile-question...

[Kelly Burke Makuch]

My son's teacher recently had a baby and I wanted to cast a tile of the baby's foot. I have taken an impression of his foot with dental alginate and poured a plaster cast. What medium should I use to now make a negative cast for the positive glass foot?

Should I mix up some hydroperm-wait until it's nearly set the impress the plaster (Pamed) foot into it?

I've only casted making a "sculpey" frog on a lilipad pos. then hydroperm.neg. I don't want to have to destroy the plaster foot in any way--have to keep the options open...

Any suggestions? I checked the archives and couldn't access anything.
Thanks!!!! Kelly

[charlie holden]

If you still have the alginate original, I would make another alginate positive from it, then make a plaster/silica negative from that. Cast your glass on the plaster/silica.

You could also use silicone or polyurethane rubber for the positive instead of alginate. It is hard to take a plaster cast from a plaster model unless you are sure there are no undercuts.