Ball-jointed dolls are strung with elastic string. It's a cord consisting of many rubber strings covered with a braid. When you buy a doll it's already strung in the most cases, or even if it's a kit the cord is included too.
No matter how high quality cord you use it stretches over time. So it's a good skill for every BJD owner to be able to restring your own doll. I even think that the dolls should be restrung at least once a year - of course, if you want them to pose nicely. You can tighten the cord a few times, but eventually it becomes too loose so you have to replace it.
It's usually sold on many BJD sites, but also it's sold on Ebay, Aliexpress or elsewhere on the Internet as "bungee rope cord". It comes in a variety of colors, so if you need some exotic color like blue or green you'd better search for a bungee cord because doll sites usually have only white, beige and maybe tan cords.
If you need a very thin cord for restringing a jointed hands you can search for a "rubber jewelry cord" or "elastic jewelry cord". Don't go for silicone ones: you still need a cord in the braided sheath!
It's always better to buy more, so you can try several stringing methods and pick the right one for your doll type. The cord isn't too expensive, so 2-3 meters for 60-70 cm high dolls, 1.5-2 meters for 40-45 cm high dolls are enough. 1 meter of a thin cord is enough to restring 2 pairs of jointed hands.
The thickness of the cord highly depends on your doll and the type of stringing that you'll be using. There is a general rule: the cord should be as thick as the narrowest place of a stringing channels allow. I'll explain this rule below. If the doll has a very narrow slits somewhere (it's usually a knee joints or sometimes an elbow joints) you can widen the slits with a rasp.
If you have some Dremel-like rotary burr equipment it would be even easier.
Please be careful and don't ruin the engineering part: the cord should go somewhere in the middle of the joint, otherwise the limb won't work correctly.
So, let's look at the standard schema of BJD stringing.
There are two strings: one goes from ankle to ankle through the head and another one goes from wrist to wrist.
There are smaller S-hooks in the wrists and ankles that cling to jumpers in the hands and feet, and a big S-hook in the head that is put on a base inside the head. S-hooks are usually made of steel to withstand the tension of the cord.
Sometimes doll sculptors make the hooks integrated with hands and feet so they're made of polyurethane. Such hooks may occasionally break if the tension is too strong.
I prefer not too tightly strung BJDs. It's a personal preference, and it also depends on the doll's construction: some dolls may have a constructive flaws that require super tight stringing. More loose stringing has some advantages: there is a lower risk of damage of the sockets, breaking or deformation of hooks, the whole restringing process is much safer. If you tend to take off the doll's head to put on a realistic clothes without the back snaps it's also a great help.
So, lay your doll on your bed. It's better to do the restringing on the bed (or maybe a big fluffy carpet) so if you drop something it would fall onto a soft surface. Spread the doll's hands and measure the distance between the wrists. Add about 2-3 cm to that for 60-70 dolls and 1-2 cm for 40-45 dolls. Fold a piece of rope in two, pull it as tightly as you want the doll to be strung, hold next to the doll from wrist to wrist adding allowances. Mark the required length or just hold it with your fingers and make a knot.
String the hands, test the movement. If it's too loose untie the knot if needed and make adjustments. It's absolutely normal to readjust the length of the cord a few times to achieve the best results.
The same should be done for the legs, just you have to fold the cord into 4.
It's the basics.
And I'd like to offer you a smarter way of stringing that adds to the stability and keeps to hold the poses better.
One of my dolls was i-Dollstudio from Korean sculptor Andro, and she was strung in a very interesting way. I adapted this method to literally any human-like BJD. Please see the schema below.
The cord in the hands is folded in 4. If your doll has a weak, falling down hands more cord would improves the posing in the most cases. You may go down 1 mm: if the hands were strung with 4mm cord you may need 3 mm cord if the stringing channels are too narrow.
When the cord fills all the width of a stringing channel, it's much better, as it creates a core for the arm. It also greatly helps a kicky limbs to hold middle positions.
The same is for the legs: the cord folded in 4 is better than the cord folded in 2.
As you can see there are two separate cords: one is in the legs and one is in the body. I usually string the legs tighter than the body; also it's needed to have 4 cords in the neck and head because 8 thick cords is too much for the most BJDs.
I usually like to string the arms first, then the legs-body-head.
I assemble one arm, pull the cord through the torso with a pulling tool and assemble another arm adding pieces one by one and pulling the cord with a pulling tool. After the forearm is strung I put a S-hook onto the cord and then attach the hand. As I have to pull hardly I sit down and hold the already strung hand between my knees.
You can do the whole operation with a bare hands and just a ribbon as a pulling tool, but it's better to have some dedicated stuff that will be described below.
I usually start assembling BJDs from the legs, though a lot of owners can do the same from the head - it's just a matter of taste.
If the stringing is done according to a standard type I string the legs, attaching them to the pelvic part, the same way as I did with the arms, just you have here a nice allowance and don't have to pull hard.
Then I put a S-hook onto the middle of the cords, sit down on the bed, hold the doll's legs between my knees, then I pull the S-hook with a pulling tool through the belly, torso or whatever pieces your doll has, to the neck and finally to the head. Then I rotate the S-hook putting it on the locks in the head.
If the stringing is done a smarter way, with a two separate cords in the body and legs you have to string one leg, then pull the cord into the pelvis, tuck the middle of the body cord under the legs cord and only after that pull the legs cord out of the pelvis and assemble another leg. That's because when both legs are strung it could be hard to pull the body cord under the legs cord, especially when the pelvic part is too deep.
When you're done with the legs put the S-hook onto the body cord and assemble the body and the head.
There are pulling tools with a hook and a handle that are sold on various BJD sites.
Never used them in my life so I can tell you nothing of those.
I use a piece of a thick copper wire (at least 1 mm thick, 1.5 mm is better) folded in two, the length of the folded wire is at least 35 cm. It has several advantages:
- you can put multiple doll pieces on it and assemble the 60-70 cm doll's arm in one take and a leg in two takes,
- the softness of the copper wire allows you to bend it while you pull closer and closer to your hand so you don't need to take your hand too far,
- unlike ribbons, it's stiff enough to go through uneven, bent stringing channels,
- unlike a pulling tool, it won't deform from even the hardest pulling: the deformed hook can be stuck in the stringing channel while the folded wire won't do that.
I use my copper wire to string both 60-70 and 40-45 dolls. I have a small steel wire folded in two for tinies.
The worst thing that could happen to your wire is breaking in the place where it's folded. Just take another wire.
Also surgical forceps aka hemostats are a great help in stringing dolls. If you ever had an injuries because of S-hooks bumping into your flesh you understand me.
When you pull the cord out of the arm, leg or neck and have to put S-hook onto it you can hold the cord with the forceps keeping it from running back into the stringing channel and having two free hands.
A properly strung doll poses nicely, but hot glue sueded or even sueded with a pieces of a leather suede doll poses like a dream. Please stay tuned for the tutorial on sueding!