Honestly, the best advice would be to give up and just save up the money to buy a doll. The necessary skills, material cost, tools, and artistic talent required to make a silicone doll are pretty ridiculous. But since saying that would be very helpful, here goes.
1: Create polymer clay for body and head what you like (for example I want to make my favorite "Mihoshi Kuramitsu" from anime or others) .
Don't use polymer clay it is one of the more expensive clay mediums. The profession clay of choice is Chavant NSP; its a great sculpting medium, holds detail well, and takes textures like a dream. Its also far cheaper in bulk and less perishable, as the solvents in polymer clay evaporates over time . Cheaper still would be water bases clay. Just wrap it in plastic occasionally and mist it with water you can a water clay sculpt soft for years.
You will need an armature to support a clay sculpture of this size. So you'll need some plumber pipe and fittings. For the actual skeleton in the sculpture you can use electrical or copper tubing. You'll also want some small cell insulation foam. A life sized clay sculpture will weigh a good deal more than 100 lbs. You can laminate sheet of foam together to make the rib-cage, pelvis, skull, as well as the upper arms and thighs. Which will save you allot of clay, hours of lay up time, and is cheap to boot.
Both ReynoldAM and Smooth-on sell Chavant clay cheap. I get mine for $5.50 / lb in buy the case. For water clay just Google pottery shops in your area, your can get 50 lbs for around $15. Polymer clay costs like $8-12 / lb.
2:Put alot plaster paper(wet) or alginate mold on polymer clay's front and back. Wait until dry hard then cut side of body's neck to feet and remove plaster paper careful from polymer clay. Head,hands and feet too.
I can see your plaster and alginate mold idea working. Your best bet would be to use fiberglass. Pro manufacturers all use it for a reason. Its strong, lightweight, holds a detail easily, is relatively cheap and can be repaired if damaged. if you have a: alginate, silicone, or urethane mold and screw up you'll need to start over.
Your local library should have books on working with fiberglass.
3:Build pvc skeleton from pipe or hose tube.(need help)
This is probably the easiest part. Just search for cloth+doll in the inventors forum. There are plenty of pictures and descriptions. You can also search the Teddy babes forum their are a few home build skeleton threads there as well.
4:Put pvc skeleton inside of dry of plaster paper's front and back together tighter.
This is probably the hardest part of making a doll. It's not trivial at all. If you do it wrong the skin can be to thin or thick in areas. The limbs won't function correctly and can even break trough the silicone skin. From, what I've seen it appears that most manufactures use small pins or bolts to lock the skeleton in place. Then pour the silicone. Later the pins are removed and small holes are patched. You can see this in some production photos of unfinished Sinthetics and Realdolls.
5:Put non-toxic silicone into hold of dry plaster paper wait for hours.
Your missing some steps here. You'll need to make a foam core for the doll's: rib-cage, pelvis, skull, as well as the upper arms and thighs. This is a good and a bad thing. On one hand you save a ton on expensive silicon rubber, while making the doll lighter and easier to use. On the other hand you'll need a number of separate molds, and the foam to make those cores.
You'll also need 5-8 gallons of silicone for the doll. Assuming you don't screw up and need to start over.
You will also need some expensive equipment to would with silicon rubber. At minimum you'll need a large vacuum chamber and a strong vacuum pump to evacuate the rubber. If you don't the doll will look like Swiss cheese and silicone body will be prone to damage.
I guess maybe i'm doing right but i have problem with number 5.
Do i need Gel-10 or Ecoflex® 00-30 from
http://www.smooth-on.com/?!? Or other?
That's why i'm still try find "step by step" of silicone.
Thank you for reading.
Your best bet is to go to Google Reynolds Advance Materials, see if they have a distribution center in your area. They and Smooth-on periodically host seminars on working with silicon.
I should be mentioned that your looking a minimum several thousand dollars to do this the right way. You'll also need space to work and assistance during most of the stages of construction. You might want to re-consider, and buy a cheap/used doll. If not, then start with something small like a head or a quarter torso. Even, Toonist from Private Island Beauties start out small with sex toys before jumping to full blown dolls.
I have a fully sculpted torso, and a quarter torso shelved due to cost. Now, I'm working on a series of cloth doll. Vastly cheaper in terms of material cost; and cloth doll making info is readily and freely available.
Good luck with what ever your decide.
