Study topic: Making a large ball joint type love doll.

rubherkitty · Post by **rubherkitty** » Tue Nov 03, 2015 12:07 am

Looks good. I assume the mating surface of the thigh to pelvis is a perfect circle?
I added a bunch of bondo to Janell's thigh so it is more oval. Looks ok when she's standing, but when her legs are kicked up the tops of the thighs protrude out the back like wings! LOL

MannequinFan · Post by **MannequinFan** » Tue Nov 03, 2015 5:02 pm

Yep, the joint surfaces are perfect circles where they mate. It took a little work to get that to happen and not look too goofy.
On the subject of coating foam, here's a couple of Youtube vids I found that show coating foam with roto-casting type urethane resins.
Kind of a cool idea that might work well for this application. One is using Smooth-On 65D resin and the other is from BITY...

https://www.youtube.com/watch?v=MDwQg6CX25A
https://www.youtube.com/watch?v=VWkch-QEGkI

Here's something interesting...
Stryo Wars!

She found that Glidden Gripper paint primer worked better than anything else for gluing styrofoam!
http://www.homedepot.com/p/Glidden-Prof ... /100157932

https://www.youtube.com/watch?v=rnOegaOKu38

MannequinFan · Post by **MannequinFan** » Wed Nov 04, 2015 3:53 pm

To complete this little exercise I wanted to see how the thigh section could be done completely with printing.
It's actually feasible (just barely) by splitting the leg sections into 2 "D" shaped thin open ended shells that would assemble onto the bone.
The largest piece just barely fits on my printer but it still works. After assembly the thigh could be filled with expanding foam for extra strength.
9 pieces counting the pin - about 27 hours of printing and about $20 worth of plastic with the value line stuff (643g or about 1.4 pounds).
I found that by going with a slightly thicker layer setting (.25mm instead of .20mm) it cuts the printing time nearly in half!

27 hours isn't too bad - considering the time it would take to cut foam, assemble and fill/finish and coat with resin this may actually take less time and be cheaper.

: printed thigh construction.jpg (697.97 KiB) Viewed 2092 times

rubherkitty · Post by **rubherkitty** » Wed Nov 04, 2015 4:23 pm

MannequinFan wrote: 27 hours isn't too bad - considering the time it would take to cut foam, assemble and fill/finish and coat with resin this may actually take less time and be cheaper.
printed thigh construction.jpg

Makes sense to me. The upper 4 pieces would need to be printed anyway. And then the knee printed. You'd have to change to the foam system and graft that in to save on 4 printed pieces.

I watched the 1st video above. Good info. Will try to watch the others too.
That guy that built that iron man suit could have made a pretty nice love doll w/ all the time he's put into that suit! LOL I think I would have spent my time building a silicone doll manufacturing operation and been cranking them out at 5 grand a pop.

MannequinFan · Post by **MannequinFan** » Thu Nov 05, 2015 12:36 am

Yay, I think I may be on to something here!

Going back to the 4'-6" model the torso lays out perfectly with four 5" high sections.
Using the same concept as the legs each section would be 4 pieces and could be simply screwed together at the small flanges.
During assembly the horizontal joints could be backed up with Aves paste for reinforcement. Like the legs, the torso could be filled with rigid foam after assembly.
The sections would take about 10 hours of printing and about $8 of plastic. Not bad at all.
Probably take a full spool of plastic to do the whole torso, so around $30-$40.

: printed torso construction.jpg (618.41 KiB) Viewed 2069 times

BTW RK, Afinia is running a special on the smaller printer like mine for only $999. Cheapest they've ever been.
I paid $1600 for mine 2 years ago.

rubherkitty · Post by **rubherkitty** » Thu Nov 05, 2015 10:51 am

Sounds like your printer will be helping to keep your place warm this winter!
I won't have any spare $ for a printer for many yrs. I will wait until my doll making venture gets closer to happening. By then I may be able to get a bigger one for a good price too.

Looking at your design, you could actually screw 3 of the sections together then have to glue the last. Or maybe screw all together if the neck has a hole where you can stick your hand down in or a very long screw driver.

Are the sections just going to butt together or have a overlap? If they are just going to butt, and you are going with the pegs only I would make a 6 - 8 peg connection. Or you could make some alternating pattern overlapping tabs to keep flex to a minimum. Of course any type of section overlap will make the sections longer on the vertical and won't fit your printer.

MannequinFan · Post by **MannequinFan** » Thu Nov 05, 2015 2:57 pm

Probably a good idea to wait on the printer. No matter when you buy one though, it will be obsolete by the time you open the box, lol.

I would screw all the sections together and just stack em up using Aves paste as an adhesive. With this design I'd be depending on the rigid foam fill to give it strength. The small dowels would be mainly just for alignment purposes. I think with a resilient ABS skin and rigid foam fill she'd be nearly indestructible.
I think the foam fill could also help make her feel warmer to the touch and not sound like she's hollow inside - maybe a bit more realistic feeling although still lacking softness.

ETA: Looks like the 2lb trial kit of the Foam-it 3lb stuff would just about do both thighs and the torso. The kit gives about 1000 cu. in. and the volume of the torso and thighs to the outside surfaces is 1039 cu. in.

rubherkitty · Post by **rubherkitty** » Thu Nov 05, 2015 3:54 pm

Yeah, I'm not familiar w/ the Aves paste. If it really bonds well to the ABS it would probably be fine. Maybe smear a thin coat on the inside around the joints. Are you talking about using rigid foam like Great Stuff or some type of soft foam from Smooth-On? Another reason I mention the extra dowels is some of that foam will expand w/ great force. I was thinking it might swell out some edges of your sections, but not the section on the other side.
I use some of the Great Stuff on the 2x6 door frame of my old workshop and it bowed the frame in where I couldn't operate the door!

Speaking of hollow, I had a heavy charm on a chain necklace for Nikki, but it would bounce against her making that hollow sound so I took it off. Now she only wear tight fitting things.

MannequinFan · Post by **MannequinFan** » Thu Nov 05, 2015 5:36 pm

Aves Apoxie Paste is fantastic stuff - it's spreadable like bondo instead of being like a putty. Kind of like sticky peanut butter.
It's also non toxic which is a big plus. It cures in 24hrs to a hard plastic just like 5 min. epoxy.
This is what I use as an adhesive for all my Eva mods. It's great as a filler or as an adhesive.
https://www.avesstudio.com/apoxie/apoxie-paste

I'm thinking of using the rigid foam from Smooh-On - the Foam-it 3 lb stuff...
http://www.smooth-on.com/Rigid-and-Flex ... index.html

I think as long as there is plenty of room for the foam to expand there shouldn't be any problems.
A good plan would be to fill in two sections instead of trying to do it all at once. The highlighted area shown below is about 588 cu. in. - taking out the FL insert and thicknesses, half a kit (about 15 ounces) of foam should be a little short of full.

The top section of the torso would be cut back so the shoulder joint blocks could be installed after. I might want to leave these removable in case the joint needs to be revised or improved (something I learned with Abby).
This would also allow the joint to printed in the other direction for better quality on the socket.

: torso foam fill.jpg (283.72 KiB) Viewed 2011 times

rubherkitty · Post by **rubherkitty** » Thu Nov 05, 2015 7:36 pm

Yes, I've heard you mention the Apoxie paste before. I guess just calling it Aves threw me off. I'll have to buy some to ck out what I can do w/ it. Bondo is a good filler, but really has no gluing strength.

The 3lb foam may flow better when expanding being less dense. Maybe have a knife on hand to cut a hole in the center if the top part cures to fast and the core of the foam is still expanding? I assume this is a chemical reaction cure and does not rely on air.

MannequinFan · Post by **MannequinFan** » Fri Nov 06, 2015 12:28 am

Here's some knee joints!

120 degree limit should work nicely for kneeling and most positions.
She'll be able to hook her legs around you in missionary...

: knee joints.jpg (535.53 KiB) Viewed 1984 times

rubherkitty · Post by **rubherkitty** » Fri Nov 06, 2015 10:55 am

That's an amazing knee joint. Can't wait to see the details.

Fiberglass guy · Post by **Fiberglass guy** » Fri Nov 06, 2015 12:31 pm

Well I LOVE where this is headed! A few things I'm noticing and I have been wondering myself how to remedy! The hollow sound of MQ's drives me NUTS, I have a suggestion and it may be pretty easy and cheap! I use the expanding insulation foam sold in hardware stores to fill all kinds of stuff and it may work to deaden the sound a lot! You wouldn't even need to fill the whole MQ torso just enough so it goes from front to back or side to side! Even a black of foam spanning both halves would do the trick, but no clue how you would gain access unless you were doing extreme mods like I am....I mix bondo and fiberglass resin together with some lacquer thinner when I need adhesive qualities, but have never just left it at that for long, usually skin over it with actual fiberglass cloth, but it does help "tack" things where I need them when testing limb positions etc..I think if you printed "masters" for these parts they could be molded and cast in just about anything...however your price estimates look VERY reasonable and I may spring for some of these parts, would be cheaper than carving up yet another MQ to get less than perfect results!

MannequinFan · Post by **MannequinFan** » Fri Nov 06, 2015 2:40 pm

Hey FG, thanks for your input man!

You should seriously consider getting yourself a little printer. These Afinias are very easy to use.
In the long run may save you $$$. I could just send you the print files and you could print them yourself.

Just to clarify for everyone, the prices that I mentioned above are my own material costs, not what I would sell them for.
Eventually my goal would be to make downloadable kits available for people to print on their own printers, but before that could happen a prototype would need to be printed and assembled to prove that it works.

At this point after all my studying and playing around I can say that a 4'-6" (4'-9" with heels) doll is definitely doable on a small home printer.
Anything larger would probably become very difficult unless you own a larger printer. All it takes is time and a few $32 spools of filament.
The nice thing about printing is that most of that time is "printer time" not my actual time. I can go about my day doing other things while the printer works.