Skeleton: Flexi skeleton / loose joints
Production date: Dec. 2019
Issue
I had ordered the version with loose joints. As expected, all joints were a little bit looser, compared to the state, when Mariya arrived. The neck was stiff to begin and the head was good posable. But after a month, it can’t hold its position anymore. It flops forward or backward. Rotating or lean to side is still stiff. So it's only one joint, which is affected. I had contact with another TFD member and apparently I am not alone with this type of issue. I am sure, SANHUI will do the best to improve this joint, but for those, who already have their dolls, I will share my experience, how I will fix it
.Video
I had the possibility to see a short video from SANHUI for this OP (had it from another member). Only the tightening action is visible, not the whole repair. The bad thing is: it needs a long cut (estimated 12cm) on one side, to simultaneously get access to the other side. It might be difficult to glue that long curved cut in an accurate way together again. The video itself could also scare some members
. I’m not owner of this video and so I don’t want to share it.Experience
I have thought about, how I will do this OP and how I can avoid this long cut. I have seen some videos of other dolls/manufacturers, how they fix something. I have already some first experience to glue some smaller tears. So I am optimistic, that I can fix a cut with a length of 3-4cm. But I have never done such an OP and probably the most owners not either. So, I will try to do a step by step manual. Feel free to profit from my experiences/mistakes and correct me, when there is a better practice for a specific action. My focus is not to fix it fast, my focus is an OP with an minimal need of cut, without any visible remains after it's done.
If I go a little bit too deep into detail: Sorry for that! I am an perfectionist and I am sure, good results can also be achieved otherwise
.Preparation
Plan:
Instead of one long cut, I choose another way. To tighten the joint, I must only have access to the bolt and the nut. For this, two small 3-4cm cuts on both sides of the neck should be enough. Glue together again should be easy then. Based on the video, I expect the nut on the right side and the bolt on the left side. Ok, this could absolutely be random. But I will start with the right side. With some luck, I can tighten the nut, without to hold the bolt. This works in some cases and would avoid the second cut on the other side. (In end, that was a nice dream -> two cuts are necessary).
Locating the joint:
I know how the joint looks and where it should approximately be located (based on video). But I will know it more precise, to not be forced to cut more than necessary. For this, I took two photos of Mariya’s head. The camera is on a stative as far away as possible, to avoid some perspective distortion. The camera is placed on her side, it’s zoomed fully in, so that the seam on the head is well visible. Between the two photos, I have only tilt the head, nothing else. On my PC, I have mixed this two photos and added this blue lines along to the seams. The cross product of the lines must be the approximately location of the joint: 6.5cm below the ear along the seam (based on the Maria head – Nonoka could be different, if she will have this issue too). When I put my finger on that point and tilt the head – I feel, that this point is exactly the rotation center. (In end, the exact location was 1cm lower – 7.5cm below the ear. But this shows me, that my locating method was not bad.)
Material, needed for the OP:
• Ruler & pen
• Cotton swabs and maybe some makeup pads
• Isopropyl alcohol to degrease/clean
• Scalpel with blade Nr. 10 (ability to cut straight/clean/deep). Don’t use a cutter for this OP. It’s too big.
• Tweezers
• 2 x ratchet with 10mm bit. No chance to access with a wrench! I had to go buy the second rachet during the OP.
• SmoothOn Sil-Poxy glue (others might work too)
• Spatulas to apply glue (in my case a handy repair kit)
• Medical tape (holds better than scotch tape and lets passing air through)
Cleaning all the tools is necessary. They must be free from dust, dirt, oil or grease.
Preparation of the body:
The body lays on the side on my bed. I have comfortable access to the neck on the right side. The head is in a neutral position, the seam is almost straight and the silicone on the side of the neck is not compressed or elongated too much. The neck is cleaned from powder and dust.
Operation
Step 1: Mark
Mark on the right side of the neck that joint location 7.5cm below the ear and on the seam. I draw it on a piece of tape and also the start/end of the planned cut. In fact, a 3cm cut was too short to get access. I had to do a 4cm long line – 3cm about the joint location and 1cm below. Reason: I don’t want to go too deep in the shoulder.
Step 2: Cut
Take the scalpel and cut on the seam belong that marked line. Use not too much pressure. After the first cut, spread the silicone with two fingers, to cut step for step deeper, until you reach the end of the silicone layer after 25-30mm. Doing this in a clean way is a little bit tricky. It takes it time. Avoid to damage the outer silicon edges with some accidental cuts! Also keep the section clean.
Step 3: Locate the nut
After the layer of silicone, there is some foamy material inside. Put your finger in and try to locate the nut. The nut is located about 35mm deep. It’s a little bit more behind the seam line. Rotate the head, so you can feel It better. Cut away the foamy material, that covers the nut and remove it with tweezers.
The joint rotates, when the head will be rotated too. Use this effect to find the nut or align the joint in an good position: Only few foam have to be removed: Bingo! There It is: It's exact position is 7.5cm below the ear: Place the body on the other side and repeat this same steps there.
Step 4: Tighten & check
Insert one ratchet with a 10mm bit on each side. It needs an respectable amount of force to tighten it. (The angle of rotation on the ratchet was very low – less than 5°. I also heard a crack noise – suspected explanation for this on end). The head joint is probably much stiffer now – in my case stiffer then to begin. I leave it that way, so it wouldn’t bother me, when it gets a little bit looser again. Remove the ratchets and lay her on her back or sit her on a chair. Do the head hold now? Tighten it a little bit more, if it is still floppy. Move the head several times to check, if it goes looser again. (Even after 50 tilt movements, the head was still stiff on Mariya).
Step 5: Align & clean
Align the head again in its neutral position. The cuts should be aligned well by itself. Take several cotton swabs with isopropyl alcohol and clean the inside of the section and then the outside. It must be dry, absolutely clean and free from grease.
Step 6: Glue
Glue in 2 steps with a delay of some hours. Reasons: The pot time of Sil-Poxy is only 5 min. You have not enough time to concentrate on both sides. Prepare some strips of medical tape, so you can take it with one hand later. Now, put some glue on an (cleaned) spatula and apply it on the full surface of the section (both sides). A thin layer is enough. Align the edges exactly and press them slightly together. Hold it with one hand. Remove the rests of glue with an dry cotton swab. Clean some glossy rests with an additional cotton swab and some isopropyl alcohol (but not too much, that it would flow into the gap). Still holding it, take a piece of tape and put it on the well aligned cut, without to press to much on it. Add some more tapes, maybe with a little bit of tension. Repeat this for the other side after some hours. Don’t touch it anymore for at least 24h.
Step 7: Check & (hopefully) be happy
On the next day, remove the tape gently. If it still smells from glue, wait another day. Maybe, the deeper layers need more time to dry. Some rests of glue can be rubbed off with your fingernail. Some rests of tape can be removed with isopropyl alcohol too. Maybe, you will see some marks of the tape now. No worries, this will disappears by itself. After powdering, you shouldn't see anymore. If there are some imperfections or a small scar, this will mostly be hidden by the seam. If there are still small cracks, fix it with a little bit of glue on a toothpick.
Cause
As seen at the corresponding photo about, the bolt is truncated to align the nut. Also, there is a welding point on it. I think, it should prevent, that the nut can loose itself. So, the nut can not be the reason, why the neck joint went looser. It must be some general wear on this joint or on it’s washer (haven’t see anyone, because I didn’t remove more foam than necessary). Maybe, SANHUI could only increase the initial torque for this nut, to prevent the same issues in future? I hope, they work on this and will find a solution
.Mistakes
The crack noise, I heard, must be the breaking noise of this welding point. Unfortunately, I remarked this welding point much later on the photo, after I had already fit all together again. So theoretical, this nut can loose by Itself now. And in fact, it do already a little bit again
. To prevent this, the nut should be removed, so some Loctite (nut locker) can be added on it. But that overstanding welding point would probably prevent to be able to unscrew that nut, except you will add some violence. Grind down the welding point is impossible with my method (no space). Recommendations
I guess, I will have to do this OP again in near future and try to remove the nut and add some Loctite
. So, I recommend to avoid to do this OP without to lock the nut! My second recommendation is: There is no need to immediately close/glue the cuts. Put only a tape on it and test for some days/weeks, if that joint keeps stiff.Conclusion
I think, when you are well prepared, then this OP is not really a hard thing. Cutting this deep layer of silicon and simultaneously spread it, was not as easy as expected. Locating the nut and remove the foam needs some time, but then, the worst is done. Tighten the joint and glue together is much easier. I was almost successful with my method – and the result looks satisfying. For the moment…
OP story
Click here for the associated OP story...
