Doll head quick release mechanism repair

siliconefun · Post by **siliconefun** » Sat Mar 14, 2020 6:09 am

Hi dear 4woods friends,

today I will show you how I repaired the head quick-release mechanism which broke on Mia's original 2012 standard silicone head during a shoot at the UK Doll Meet 2016.
This is very annoying because the head is no more secured and as soon you tilt the doll's body the head comes off. The risk that the precious face got damaged is just a question of time and the worst case

4woods heads are built on a base of a fiberglass shell on which the face is poured with silicone. The quick-release mechanism is inside this shell so there's no access to do a repair when it fails.
The only option is to create an 'access hatch', large enough to do work with tools.

We're now in the surgery room (or hobby room

) and Dr. siliconefun anesthetize patient Mia in a deep

: General-anesthesia.jpg (59.42 KiB) Viewed 550 times

Step 1

: Tracing and cutting of the thick silicone layer.; 20161215_182159.jpg (213.47 KiB) Viewed 550 times

: The silicone layer is now removed, the fiberglass skull shell appears.; 20161215_182208.jpg (276.69 KiB) Viewed 550 times

: Tracing and cutting of the fiberglass skull shell; 20161215_182901.jpg (332.83 KiB) Viewed 550 times

Note: I protected Mia's face with a cotton cloth....now it get's dusty...

: Used tools to proceed to the next step.; 20161215_184323.jpg (593.87 KiB) Viewed 550 times

: Small holes are drilled in a row to insert the saw blade.; 20161215_183536.jpg (523.46 KiB) Viewed 550 times

: The skull shell is now open and reveals the hidden locking mechanism.; 20161215_184220.jpg (512.38 KiB) Viewed 550 times

HUH!! There's no brain inside

The reason that dolls don't speak

Step 2
The next series of pics reveals the hidden interior:

: Detail view.; 20161215_184823.jpg (510.08 KiB) Viewed 550 times

: On the side of the head, an ⌀ 8,0 mm hole was placed to insert a pin extractor tool.; 20161215_190454.jpg (309.97 KiB) Viewed 550 times

Note: The silicone was removed by the use of an ⌀ 8,0 mm hole punch tool. Reuse this piece as plug when finished.

: Removal of the pin.; 20161215_190804.jpg (412.52 KiB) Viewed 550 times

: Detail view.; 20161215_191211.jpg (536.69 KiB) Viewed 550 times

siliconefun · Post by **siliconefun** » Sat Mar 14, 2020 6:09 am

Step 3
Examination of the parts

: Quick-release bracket + pin + spring; 20161215_191305.jpg (379.86 KiB) Viewed 550 times

: *
1) Crack
2) Broken latch; Drawing1.jpg (571.05 KiB) Viewed 550 times

Step 4
Back on the PC and by the help of a digital caliper, a CAD-drawing was done and also the requested files to produce the part on my CNC-milling machine.
However, I decided to go 'old school' and machined the bracket on the milling machine in my Hobby room, it took nearly 2 1/2 hours and the replacement part was ready for his new destination.
Used material: Polyoxymethylene (POM)

: The nearly finished DIY-replacement part.; 20161216_175321.jpg (412.82 KiB) Viewed 550 times

: Original versus DIY:
Proudly made in Luxembourg.; Drawing2.jpg (690.24 KiB) Viewed 550 times

: Some preparation before assembling...; Drawing3.jpg (859.54 KiB) Viewed 550 times

: Assembling of the mechanism.; Drawing4.jpg (931.28 KiB) Viewed 550 times

: Detail view.; 20161216_190155.jpg (335.46 KiB) Viewed 550 times

: 1st test: the new quick-release bracket works perfectly!; Drawing5.jpg (528.28 KiB) Viewed 550 times

Step 4
Time to close Mia's skull!

: 4 cardstock straps are placed inside the skull to hold the fiberglass cover in position.
These straps will be removed later when the silicone layer's cured on the fiberglass.; 20161216_194050.jpg (287.33 KiB) Viewed 550 times

: The fiberglass cover is now fixed.; 20161216_194316.jpg (321.48 KiB) Viewed 550 times

: The silicone layer is glued with a few dabs of RTV-1 silicone, just to secure the position.; 20161216_201825.jpg (278.26 KiB) Viewed 550 times

Note: to guarantee a suitable bond the fiberglass cutout was cleaned with acetone and threatened with silicone primer.

: Added more RTV-1 silicone to guarantee a final bond.; 20161216_211001.jpg (415.34 KiB) Viewed 550 times

- Time to take a meal while the sil cures -

After some thoughts I decided to install the finished 'access hatch' without gluing to the skull, just like a removable cover of a box. It looks and works fine and the wig covers the surgery traces.

Hey, we don't stop until we reach the goal.....but it's sometimes not that easy....THAT's the challenge

- SF -