The silicone hands for my character don't seem to be holding up, the wires can be seen through in some spots and poke through some fingers. I'm wondering if the fingers are too thin and the hand too small for enough silicone to support the wires inside. Any tips? Do you think I should re-sculpt a bigger hand with thicker fingers to make a mold of for new silicone hands?
When this once happened for some of our puppets during a commercial shoot. I got rid of the wires in the troubled fingers and pushed in some new Wire from the fingertips. I Found it quite easy to guide the wire through the silicone, and keeping it in the middle of the mass like that.
If you choose to cast some new, dip the wire armatures of the hands in a small batch before putting it into the mould. Letting it cure first.
I only do silicone hands when they are part of a silicone body where it needs to be seamless - for clothed figures I tend to use foam buildup for the body and build the hands up with latex over the wire. Only the head is silicone, most of the time.
But when I do make silicone hands, there are two things that I found helped -
1) I use two 1mm wires twisted together in each finger, and where possible it is one wire that goes to the fingertip and bends back, so the tip is a loop rather than a cut end. If I don't get the lengths of the finger wires right and have to cut the end off to fit the mould, I put a blob of epoxy glue on the tip so it is rounded and not sharp. For some hands I use 3 wires per finger, one is a loop and the other is cut at the tip, so that needs a blob of epoxy as well. I join these thinner wires onto the arm wires in the forearm, with a bit of aluminium tube. (Some people use 2 sizes of square brass tube, one inside the other, so the hand can be removed and replace in case of breakage or were.)
2) I spray glue some foam bandage underwrap onto the hand. It is very thin, 1mm or maybe less, but it gives a rough surface that the silicone can grip onto. It also adds a slight layer of padding over the wire. I then paint a little silicone onto it, so that adds a layer of silicone, which helps to locate the wire in the centre of the finger and keeps it from touching the surface of the mould. The soft silicones used for casting puppets don't stick that wet to bare wire, especially a single smooth strand. The spray adhesive for upholstery foam I use does stick to wire, and so does contact adhesive.
If you don't have the thinner wire and have to use single strand, say of 1.5mm (1/16th") wire, glueing the foam on to give it a surface the silicone can stick to is even more important.
Another technique is to take some braided string (I use kite string), remove the core and slide the sheath over the finger wires. I put glue underneath, and it means you don't have to do as much trimming as with physio wrap.
Had to look up the physio wrap, and for what I could make out online, it looked a lot like the ordinary household wrap. Is it any different?
No, physio wrap is the stuff used for sports injuries. It is a roll of 1mm thick foam plastic. It took me ages to find it before I learnt what it was called!
Physio wrap, foam bandage underwrap, sports tape underwrap, all appear to be the same thing - very thin soft urethane foam, usually on a 70 - 75mm wide roll. Apart from glueing it onto the wire to give the silicone a porous surface to grip onto, it is also good for smoothing the shape of cushion foam that has been carved with scissors. A layer of the physio wrap lightly stretched over the top flattens out the peaks.