Vinyl Head Shrinking:
The Fast Method
Please be sure that you have read the Introduction to Vinyl Head Shrinking before taking on this tutorial. There are a few chemical conditions talked about there to consider before jumping in.
The slow method is safer for the doll, but with that in mind, if you are ready to continue, you can either watch the video below,
or read the written version below that.
So, you like to gamble eh? Or maybe you are in a hurry, or just want to try it for fun, etc. Whatever your reasons, continue!
Step 1: Gather materials
Materials you will need:
Glass jars: I use 16oz 3.5"x3.5" mason jars for what these days are your average 11" tall doll. It is VERY important that you use a jar that is large enough. 8oz 2.5x4" jars are NOT large enough and your head will crack up and fall apart without enough room to expand.
100% Pure Acetone: Acetone is commonly sold as nail polish remover, among other things. Wherever you go to shop for your acetone, make sure that it is actually pure, with no other chemicals, like things to strengthen your cuticles or want not. Any impurities at all can greatly stunt the effectiveness of the acetone or result in unforeseen side effects. After all, diluting it with even as little as 10% water is what weakens it enough to result in the slow method we are using here. Weak enough that it doesn't even remove the face paint.
Water: Easy enough. Plain old tap water.
Springy Stuffing (optional): If you are working on a head that has very thin walls like Rainbow High, they may be susceptible to sagging after they have been softened by soaking. If this is a concern, you can put some stuffing inside the head that will help it to keep its shape, but make sure not to stuff it tightly, or that could cause other kinds of distortion or tearing.
Step 2: Prep/Cleaning
To optimize results, you need to reduce as many contaminants as possible so you take the applicable steps:
1. - Remove hair if you are going to reroot. This will also reduce the amount of acetone used getting soaked up in the hair.
2. - Wipe the faceup. The paint is going to come off in the jar anyway so taking it off before the soak just keeps eliminates that much more contaminants.
3. - Wash the head. Just some dish washing liquid in tap water should suffice to get rid of any oils and grime. Make sure that the soap is completely rinsed out.
Step 3: Soak(s)
Fill the container with enough acetone so that it will still cover the head in its inflated state. It will expand quite a bit through this method. Since it's not a mixture, you can always pour more in if you realize the head is no longer covered once it's grown.
It takes about 2 hours for the head to be fully soaked through. It will be very soft and fragile at this point and you have to be very careful handling it at this stage. Try not to lift it out by the hair, try to get your fingers around the head to lift it out. It will take 22 hours or so for the acetone to evaporate and the head to shrink as much as it likely will for that particular soak. However, you don't have to wait that long before starting the next soak. You can probably start the next soak after around 12 hours. You can dunk the head multiple times for additional shrinking. Each soak breaks down more plasticizer, which gives vinyl its elasticity and that's what we are getting rid of to facilitate shrinkage. That's why the vinyl gets so hard from the process. I have many dolls that I shrank 5 or 6 years ago and they show no signs of becoming brittle or discolored defective in any way yet.
Back to the job: Rinse the hair gently to get rid of any particulates from the soak that might be clinging in there.
If it seems like the sculpt is sagging and might dry in a warped shape, you might want to put some of that stuffing in there. Just enough to avoid cave ins. Don't stuff tightly. Remember to remove the stuffing before you do the next soak.
I usually do 3 or 4 soaks, depending on what I'm going for and how the progress is looking. Sometimes even just 2 soaks can result in such drastic shrinkage that I don't have to go further.
Now the thing about subsequent soaks is that once the solution has been used, it is no longer 100% acetone. Some of the plasticizer has become leached out into it, as well as any number of unknown particulates in unknown proportions. So unfortunately, as I mentioned in the introduction, without a lot of expensive lab equipment, a lot of guess work comes into play here. Well, unless you've got enough money to mix a fresh solution for each soak. Not everyone out there is shrinking en masse like me lol.
Unless the mixture has turned a strong color (say dark pink from color leeching from the hair [funnily enough, this has never actually changed a doll's hair color in my experience]) then the worst thing that can happen if you try to use the same solution again, is that it won't be very effective. The coloring has a chance of dying the head, though that has only happened to me twice out of 14 times the solution has become colored and both were dolls that had been rooted with yarn.
Personally I usually dump the first batch of solution and then reuse it after that unless it gets cloudy or discolored.
Step 4: Things to do During Drying
There are a number of things that you can do during the final drying stage, all of them optional, depending on your desired end result. Before you do any of them though, it is a good idea to wait at least 8 hours to allow things to stabilize and strengthen a bit.
Rerooting: If it seems like it is hardening very quickly at this point, you may want to begin rerooting if you want to be finished with that before it gets too hard. You can still root in a solid head, but it's more difficult.
Neck fitting: I wouldn't put the head back on the body until it's solid enough that it's not squishy, but has some give if you squeeze hard enough. If you put it on too soon, it may melt the plastic a bit. It will likely be very difficult to get the head off again, so make sure you do everything you plan to do before securing the connection. It is a good idea to widen the inner neck hole a bit with an Xacto blade, because even if you can squish it on while it's soft, the head shape could distort a little on the lower head as it tries to shrink around the neck. Be careful not to widen the inner hole TOO much, or there will be nothing for the head to sit on and it'll just sink down to the shoulders.
Compression shaping: You can alter the shape of a head by compressing it during drying, using any arrangement you can think of. Ever After High dolls are some of my favorites out there but many of them have very round faces that I don't care for. So I use a mini-vise, rubber bands, some padding and a box to dry them in a more oval shape with a more pointed chin.
The box is to contain the configuration since rubber bands will sometimes want to slip off, or others parts pop out of place. Makeup wedges are good for padding directly between the head and the vise grips, because if you don't pad, you will end up with hard lines pressed into the vinyl from the edges. Make sure to check back every few hours to see if you need to make any adjustments as the shrinking progresses.