Hello ladies and gents, cats and kittens. I'm in the process of making a few customized My Little Pony toys for a friend and myself, and since the process has turned... interesting I thought I would keep track of it and share my progress with you!
Customizing toys is a really fun art project. Working in 3D is not something I ever ever do so it's also a bit of a challenge.
I wouldn't mind constructive criticism from anyone familiar with clay/sculpey! It's a utterly new medium for me.
Let's get started.

Here are my victims, G4 Rarity and G4 Fluttershy. They are fairly small, about 2-2.5 inches in height. They aren't quite as bulky as their predecessors, but I think the sculpt on them is absolutely adorable. The wings are especially cute!
But as cute as they are, I still have no issue decapitating them.

Removing the heads was a huge
pain. They are small and it's really hard to get a good grip on them! I ended up using an exacto knife to cut out the joint in their necks, which means my ponies' heads will (sadly) be stationary

As you can see I also removed their hair. The tales come out easy as pie, but their manes are glued in. I recommend trying to grab the chunks of glue with needle nose pliers-- the longer the neck on your pliers, the better, because the holes in their heads are absolutely miniscule. Do not use acetone or anything else to dissolve the glue, it makes everything worse! It's really hard to grab the hair and in the end you'll end up pulling out individual hair instead of large clumps >< I made this mistake on Rarity and it ended up being a huge mess! Fluttershy went much much smoother.
I used nail polish remover to rid them of their eyes and cutie marks and it
did a super shitty job. I wasn't concerned, really, since I'll be painting over them with a few coats of acrylic paint (and a matte varnish to keep it from chipping), but if you want to do your own custom pony and can find one you don't want to paint, get some real acetone from the hardware store.

Here they are with their heads glued back on. I used hot glue since I was no longer worried about the necks moving. I would imagine that if I have salvaged the neck joints your best bet would be to use crazy glue to glue it back into the body and then pop the head back on.
Now a lot of pony customs 'rehair' their ponies with new synthetic hair, but I wanted some... familiar silhouettes and knew I couldn't capture them with actual hair. So I'm using white sculpley. I did some research and knew I couldn't bake the ponies (the plastic is incredibly soft and pliable, it would melt in seconds on even a low setting), so I will be boiling my ponies. Boiling for 5-8 minutes successfully hardens the sculpley according to my research, but I'll let you know how that goes when it's time to cross that bridge!

The first rough sculpt for Gabe! I ended up scrapping this one. It has a nice silhouette but there's no volume to it. I took a good hard look at the models in PAA and came up with...

These. This is the rough sculpt for Tycho, and what I am considering the WIP of the final sculpt for Gabe. The hair has a really nice thickness to it without being too heavy. I'm really quite pleased!

Tycho's hair is being refined. Tycho was a huge challenge, and in the end he's only going to look especially good from one side-- not like Gabe, who will keep his trademark 'do from any angle. Again, this is eyeballed from the PAA models. I had a rough in place based on Tycho's Poker Night model but it didn't quite capture Tycho's unique silhouette, which in the end was most important to me. Tycho's hair does some truly ridiculous Mickey Mouse-esque nonsense.
You can see I began work on Gabe's tail here. I'm using a stick that came with a goofy little prop in a Halloween bouquet, but any Home Depot or AC Moore should have wooden dowels you could use. I'll have to measure the hole but eyeballing it it looks about 1/3rd of an inch thick. The stick ended up fitting perfectly (lucky me!) and I am molding the tail around it to give it some much needed extra support. The tail needs to be trimmed, so to speak, as I don't want it 'dragging'. Gabe's tail will be a 'proper' length, emulating his hair, and Tycho's will be fashionably short and emulating his bangs. I plan on baking the tails separate from the ponies, painting them, and then gluing them in place.

Just a slightly more up-close shot of Tycho's mane. I am incredibly pleased with it so far. The sideburn actually looks better on the other side and I will be redoing this one to match, but I can't take a photo now as my mother has usurped my camera :P
Well that's all the progress I have as of now. Crits/comments are welcome, and I'll answer any questions you may have!
Posts
Some general/generic advice:
- Pure acetone is amazing and will strip almost any kind of paint right off.
- With G3 ponies, you could back them right in the oven to bake Sculpty, with no ill effects. Now, I have NOT tried this on G4s yet. But it may well be the same with them. And I've heard of people successfully using the boiling method you mention. (Have not tried it myself.)
- Dying - You can use RIT dye (clothing dye) to dye ponies and it usually does a really nice job. This pony was done with black RIT dye:
However, RIT dye will not cover up any paint so it's vital to remove it utterly before using it.
- When painting with acrylics, a lot of very thin layers gives the smoothest look. These cheap foam brushes work well . . . dab, dab, dab!
- Removing manes. As you already discovered, it can be a pain in the ass. What I do is crop the mane as short as possible, pop the pony's head in hot or boiling water, wait for it to soften the glue, and pull the hair out with pliers from the inside. (With the shape of the G4s' heads, it might be necessary to do it from the outside, though.)
I can also give rerooting tips if you think you might do that in the future. It's a bit tedious but not really hard. Oh, and a pony's head is held in by a plug, usually you can maneuver the plug out with enough wiggling and sometimes the help of a breadknife.
Anyway, Gabe and Tycho are looking great. You really captured their hair styles, very impressive since you had to go from 2D pictures to 3D sculpture.
Edit: Also, I apologize for this being such an info dump. It's just that there are a lot of little steps that go into customizing.
That is a pretty nice 2D-to-3D translation. Any reason you're using the white Sculpey III vs. the beigey-translucent Super Sculpey? The latter always seems to be easier to get hard edges and so forth with because it's not quite as soft, and less brittle after hardening.
Commonly called greenstuff, greystuff, brownstuff, or just epoxy clay, you should be able to find some at most hobby shops. You might need to shop around a little to get a good price on a decent quantity (its mostly used for miniatures, and is sold in very small amounts).
It comes in two parts, and when you knead them together, you have about an hour before the clay starts to harden.
Homestar, your ponies look like there coming along well, and they look fantastic! I actually showed my wife this thread when I got home the day I found it.
@squidbunny It's the sculpey I had lying around! I'm really pleased with how their hair has come along, but in the future I'd like to use other stuff... as soon as I get through this half a pound of white sculpey (ah, old Christmas presents, finally being put to use).
@McGibs I work rather slow, so a clay that doesn't harden within an hour is ideal for me. I have been nitpicking these guys for just under a week now. But maybe in the future when I have more practice and am more confident I'll look into it!
@Custom Special Thank you!
And I'm not just here for replies, I also have a non-photo update as the visual difference is negligible.
But I have successfully boiled Gabe's mane in hot water, and it's hardened very nicely. I'm really pleased. I patted him down with a soft rag and he's air drying now as I finish the sculpt on Tycho. I plan on taking some very fine sandpaper + a very fine nail file to his mane to smooth it out and get the hair to a nice point. The mane kept its shape beautifully. All in all he was dunked for about 9 minutes (the hair is a bit thick in the front, so I kept him under a while). I used tongs to keep him under the water, without touching the bottom of the pot.
Tycho will join him in a day or so, once I am happy with his sideburns. It's surprisingly difficult to make them even on both sides haha. Once I get the tails finished I'll post more photos.
Edit I completely forgot to mention the mishap! The hot glue I had used to reattach Gabe's head melted, but other than giving me a newly decapitated pony there were no other problems. I did burn myself on hot glue, though... but beh. I'm clumsy. I'll be removing Tycho's head in advance, and in the future with sculpt pony heads and pony bodies separate. I'm only just remembering this now because I changed out the bandage on my thumb haha.