[foxmaster5]

'Assuming a torso mold of an actress and a set of prostheses, what would you charge for materials and labor? And for the same with three or four sets of prostheses, continually larger than the next, to swap out between cuts for the illusion of continuous growth?'

So to expand on how pricing this works out... Assuming you sent me a great life cast it would take a day or two to create both sides of the mold(a positive core and a negative cavity). It would then have to be run out of silicon and painted to look more realistic. Granted you can tint the silicon flesh colored, but additional painting is required. Then youd have to add your actress and bladder/balloon rig and lets hope it works as planned.

Now to make several different sized chest pieces you have to rinse and repeat the process only youd have to sculpt the larger chests and remold them. So the cost and materials compound with each new sculpt. Its more practical to just make one and work on making it be able to expand rather large.

Now camera angels and set ups play a large part in making the growth look more impressive then it is. This applies to what the actress is wearing as well. So the fx build is only part of the overall illusion.

"Define "firm backing". Do you mean some kind of molded chest plate that you attach the bladders to?"

So when you inflate a balloon pressure is exerted in all directions. So if you just place a silicon piece on an actress and inflate balloons or bladders behind it then it will push the prosthetic away from her real chest as much as it expands in other directions. Im not actually sure how to get around this one. By hard backing you could glue the piece to the actress with a silicon glue like Telesis Silicon Adhesive. But the pressure would eventually overcome the glue. Another idea would be to mount the prosthetic to piece of silicon covering the cavity where the bladder goes. Glue this down more permanently with a silicon caulking. Cut a hole for the bladder/hose to be inserted and when this rests on the skin it should provide a solid backing.

'Where would one obtain polyurethane bladders, anyway? Are they a thing you can DIY out of the right materials?'

Id say just use high end latex balloons. BUT there will be friction between the latex and the silicon. Not sure if this would be an issue, might lead to a rupture of latex balloon. My suggestion would be to make a balloon covering out of spandex. This should provide a slippery in-between material.

'I would think a single unit would lead to the cleavage furrow projecting outward with the rest of the breasts when the prostheses were enlarged. Would it be practical to create a separate prostheses for each breast to avoid that?'

When you do a life cast each breast should sit separate on the chest creating separate breasts in the silicon prosthetic. You'd have to have a pretty busty model to begin with for issues to occur when doing the life casting. The real issue here is how to make each balloon/bladder to expand at the exact some rate. Every balloon and prosthetic will have different surface tensions with could create an issue. Testing would be needed to see if a single inflation source(water or air hose) could just use a splitter and inflate both breasts equally.

'Bit of a non sequitor, but do you get asked to do mundane make-up a lot?'

Yes. I do FX make up on set quite frequently. Most of my time is spent at the fx shop building and molding.

If there are more questions feel free to ask. Im more then willing to try and figure out some of these issues with you guys.