Broken back repair on my Sabrina doll

[Synthian]

My doll broker her spine a little over a month after I purchased. I recieved no word from the seller, so distraught, I cut my doll in half about two inches above the belly button. the spine break was at the weld where the hip tube and spine join. it was a bad weld.

I am going to wait a bit and see if she holds a bit more and then finish getting her back together.

Do you have any pictures? The precarious part is this: when the weld breaks it takes part of the hip bone with it leaving a hole in the hip bone. This weakens the hip bone and your drilling though it also weakens it. The JB weld is probably not going to stop the hip bone from completely separating as mine did after the first surgery. For the second surgery I inserted a solid metal bar into the completely separated hip bone and for the third surgery, I used a captive shackle to hold the spine and hip bone together. Although she'll never free stand again, she can still sit and the loose hip motion more than makes up for this

My advice is do not seal her up too soon because you'll need the room to scrape off the crumbling JB weld to fit in a solid metal bar after the hip bone separates completely.

06 Clear TPE and Cloth.JPG (2.14 MiB) Viewed 106 times

[RevJack]

Scr9000,
I would hold off sealing her up. Since you didn't address the tortional issue by redirecting the twisting torque away from the horizontal pelvic pipe, I suspect the injury will reoccur very soon.
The welds don't break due to vertical forces pulling the spine away from the pelvis They break due to the tortional forces transmitted when the hips are repositioned (legs lowered or raised) which tries to move the pelvis, which is anchored to the spinal weld. The tortion at this location can tear the weld loose or tear the SS pipe in half at the apex of the pelvis.
We need to protect the spinal weld from the rotational toeque to keep the repair. Jbweld and steelstick are the most common (and best) epoxies buy are still not up to this challange.

A solid T structure sandwiching the spinal joint and extending to the thigh pipes has had the longest survival rate (as far as I have been able to determine). Welded is best, but contraindicated in most circumstances. Racing hose clamps can be sufficient if the arms of the T extend to the thigh tubes and are clamped to the thigh tubes. The spinal section of the T must stop at the back joint, allowing the joint to flex when tortion is transferred from lifting the legs.

Just my experience, but I have fixed a few broken backs and consulted on a dozen. So my experience is EXPERIENCE, not armchair theorizing.

Reverend Jack

[DCODY96]

Well it finally happened, back was broken in one of my dolls. Surprisingly it broke on one of my newest dolls, my SM175L "Sabrina".
viewtopic.php?f=11&t=124863&hilit=meet+sabrina

I was preparing her for a new photoshoot and had her lying on couch. As I lifted her feet I could feel that something was wrong and her upper torso felt very loose. I immediately knew what had happened. Photoshoot had to be postponed until I could get her back into shape.

Firstly I made a cut to her back to get access to broken part of her back.

_Sabrina_backrepair_01.jpg

Just as I suspected, back had broken at T-section where her backspine connects to her part just above pelvis.

_Sabrina_backrepair_02.jpg

_Sabrina_backrepair_03.jpg

Pipes used were very thin and normal usage broke her back at weak point.

_Sabrina_backrepair_04.jpg

I decided to reconnect her back with 6mm screw and with a piece of pipe. At the picture below I have drilled 6mm hole to lower end of her spine.

_Sabrina_backrepair_05.jpg

I bought regular plumbing pipe with inner diameter 25mm and removed some of the threads with a lathe and cut it in half. I selected one of the halves and drilled 6mm hole on it.

_Sabrina_backrepair_06.jpg

6mm bolt and washer will connect this half pipe to lower back.

_Sabrina_backrepair_07.jpg

Pipe connected to back. I used nylock bolt at upper end so that this screw could not get loose.

_Sabrina_backrepair_08.jpg

I brought a doll for like $700 less than a year ago and the back broke on it in the same exact place.

Has anyone that had this issue ever tried to solder the pieces back together? I thought about buying a soldering gun and metal working wire to fix mine. Any idea if this would work?

[RevJack]

Solder does not have anywhere near the strength needed.
If you broke a steel weld, what chance lead solder?

Reverend Jack