The Doll Forum

I've thought about using pool noodles in a stuffed fabric doll.
Now I'm thinking I may be able to use them in a silicone doll.

From what I understand of the foam core for a silicone doll is that the skeleton is put in a mold and liquid expanding foam is then poured into the mold. Some doll makers may have foam pieces cast separate then glued onto the skeleton.
Of course this is all then placed in the final body mold for the silicone pour.

It appears that some dolls silicone over the foam is only about a 1/2" thick in some places.
As I want to make a midsize doll, I'm thinking I may get by by using pool noodles that are dirt cheap and that would save a lot of time and cost. Expanding soft foam is not cheap.
Probably wouldn't be able to use the noodles at the joints as they would not bend very easy.
I figure on making my silicone about 1" thick at a minimum to avoid tearing. Places where the silicone is thin over the foam appears to be a weak spot.

Could always experiment with the noodles during R&D.

You might need a silicone primer on the PU foam first and then paint a coat of silicone onto it before the pour. If its plat silicone this process should (in theory) prevent delamination from the outer skin. I know some silicone doll mfts use PU as a foam core and that is one way around the delamination compatibility/problem other than mechanical lock methods.

I've never tried the method above but I have used a plat silicone primer to pour Ecoflex into a broken doll canal wall - the small tear was first glued with an RTV silicone, I was worried about delamination so I treated the area with primer then dribbled Ecoflex 00-30 on top and let cure. 2 years later and canal used many times over there's been no sign of any problems. Just my 2 pence worth, you could always do some small scale testing to know for sure.

Thanks
I will check out silicone primer.

I posed a question a long time ago about whether silicone should slide over joints when they are articulated and whether silicone should be attached to OR be free of the foam core, but never got an answer. But this was back when Abyss only used foam on the chest cavity and thighs.
Not sure what Abyss or DS Doll uses now.
Ruby13 uses a complete body foam cast on the skeleton then shaves it down.

I know DS uses some type of membrane or coating over their foam, but they never specified what it was. Maybe a silicone primer.
I believe one company (Anatomical Doll?) placed plastic over their doll joints to keep the silicone out.

I assume the thicker the silicone, the less you have to worry whether it moves with the limbs or if it is free of attachment and follows the movement of the limbs.
If you have silicone attached to a thigh and calf, the silicone will need to stretch on the knee cap and compress on the under side when the knee is bent. I can see having the silicone loose at the knee and maybe a couple of inches above & below.

Maybe doll makers do not take this all as in depth as I'm thinking. I'm sure TPE doll makers don't sweat this kind of stuff.

FlashGordoll wrote:You might need a silicone primer on the PU foam first and then paint a coat of silicone onto it before the pour. If its plat silicone this process should (in theory) prevent delamination from the outer skin. I know some silicone doll mfts use PU as a foam core and that is one way around the delamination compatibility/problem other than mechanical lock methods.

I've never tried the method above but I have used a plat silicone primer to pour Ecoflex into a broken doll canal wall - the small tear was first glued with an RTV silicone, I was worried about delamination so I treated the area with primer then dribbled Ecoflex 00-30 on top and let cure. 2 years later and canal used many times over there's been no sign of any problems. Just my 2 pence worth, you could always do some small scale testing to know for sure.

Absolutely agree. To prevent delam the smooth foam surface needs to be shaved off and a silicone mix sprayed over the top. This will help prevent delam of the silicone from the core.

RK the silicone primer I ended up getting was this: http://www.silicone-polymers.co.uk/pdfM ... 6-161P.pdf
Originally I wanted this primer: http://www.factor2.com/Gold_Platinum_Pr ... 0-gold.htm, unfortunately I couldn't find it anywhere in the UK so instead found the first which looks to be very similar.

Although I'm in agreement with Samara that a rough surface on PU foam PLUS painting with plat silicone (either brush or spray) should definitely improve the chances of delamination not occurring so you may not need a chemical primer on the PU. Freshly cured plat silicone will stick to newly poured plat silicone like shi* to a blanket and once cured will never delaminate providing there are no contaminants intervening. So if you can get a coat of plat silicone 'locked' to the PU you've won the compatibility battle. (In theory).

I want to make it clear that I'm certainly no expert but have got a good memory of my past research. Various techniques used by different mfts (professional and amature alike) to provide a 'mechanical lock' to materials that plat silicone would delaminate from otherwise. They all use the same principles, a rough sometimes fibrous texture and paint or pour (or both) mixed plat silicone onto it letting it cure before placing the structure into the mold for the final pour. I've seen - Fibrous string and/or bandage glued and wrapped around PU foam and even glue applied to the PU then cotton wool stuck on and pulled off to create fibres for the painted plat silicone to 'lock' into. Its basically the same principles for sticking anything to anything with any type of adhesive, keyed surfaces usually stick better as you already know.

So yup your pool noodle/foam core is not such a crazy idea for the straight parts as long as you could secure it to a skeleton properly.