Nickelodeon Metalhead – Custom Arm Mod

Regular readers already know I like the Nickelodeon Teenage Mutant Ninja Turtles cartoon, and that the action figures of the four main turtles were the first I’d bought since probably childhood. But while Michelangelo, Donatello, Leonardo, and Raphael all have elbows and knees, for the rest of the line Playmates went back to their old standard of pretending kids don’t care about articulation.

Metalhead, for instance, is only agile from the waist down.

But there is a way to improve that. In this guide I’ll show you how to add swivel\hinge shoulders and elbows, and even keep the swivel forearms!

Nickelodeon Metalhead Custom Arm Mod Guide go!


Step 1 – Obtain Parts

Jin Saotome has done a great custom Metalhead that articulates the arms. There’s no guide on how to do it, but he does explain what parts he used.

As I had a spare Titanium Man, I thought about doing it that way.

But there was something that bothered me about it once I examined the parts in person- Titanium Man’s upper arm was really scrawny, and yet over-muscled.

If that sounds confusing, think of it like this, the forearm as a whole is tiny compared to the big burly limbs of the rest of the Nickelodeon turtles, and on top of that the arm has a lot of very defined and kind of swollen musculature, which also doesn’t mesh with the style on the rest of Metalhead.

It doesn’t look that bad in the pictures, so it could be that the black paint helps obscure it.

But on top of that, I didn’t like that the elbow pads were mounted on the forearms, instead of being on the elbows. It’s better than Metalhead not having articulated elbows at all, but maybe there was another option, something different.

So I decided to try something different.

And that leads us to the point of this step, obtaining the right kind of parts to use for Metalhead. If the upper arm of an action figure from another toyline wasn’t the right size, why not use one from another TMNT?

Organic details like muscles and skin texture, of course. The turtles are rife with them and it just didn’t seem like it would fit right on a robot like Metalhead.

That’s where Stealth Tech Leonardo comes in. The arms are more cartoon accurate, with smooth details that look like blocky CGI than something organic. The shoulderpads are even more accurate to what Metalhead looks like on the show, instead of the smaller blocks on the toy. The elbow pads are even a good fit, as they’re a solid ‘tech’ style.

So for this step, go out and buy a Stealth Tech Leonardo.


Step 2 – Boil And Pop Arms and Torsos

Next we need to extract the parts we need from Stealth Tech Leonardo, and extract the parts we don’t need from Metalhead.

Using the boil and pop method, Metalhead’s arms can be easily popped out of the torso at the shoulders, and the forearms can be popped out at the swivel joint.

Leonardo, however, uses a much harder plastic for the actual shoulder joint, and it isn’t going to come out easily. Even soaking in scalding-hot water didn’t soften it enough to get the plug pliable enough to pop out through the smaller hole.

But remember, the boil and pop method can also soften glue.

And Leonardo’s torso is just glued together. :)

So pop off Stealth Tech Leonardo’s head and plop the torso in hot water. Once it’s heated up, take a sharp blade and work it around between the two halves, until you’ve got enough of a gap to use a flathead screwdriver to lever the torso apart. It should snap apart pretty easily.


Now here’s the first snag in the plan for the Metalhead custom arm mod… If Leonardo’s shoulder joint was so hard that the torso had to be taken apart to remove it, how is it going to be put in Metalhead?

Yup. Metalhead’s torso has to be popped apart too.

Execept it’s not so much of a pop as it is a pry. It’s not just glued together along the edges, but has posts inside that are glued!

The best thing to do is just take your time, heat up the torso and go slowly around the torso with a sharp blade, and eventually you’ll be able to use a flathead screwdriver to start to pop it apart.


Or you could do what I did and not go slowly, using a screwdriver through the arm hole on the torso to pry it apart.

It worked, but it also broke the pegs on the inside and the halves of the balljoint stayed glued together by snapping at the base of one side.

If that sounds horrible, it’s not. :) The edges are all that are needed when gluing the torso back together, and the head covers up the seam below the balljoint.

Here’s a picture of it.

Boil and CRACK


Step 3 – Boil and Pop Hips and Shoulders

Why does Leonardo’s arm in that picture have a black peg instead of the green one? And what’s that green stuff on joint?

The green stuff is part of another step, but the black peg is an easy answer.

Unless Metalhead is going to have green arms, Leo’s plastic is eventually going to need painted… but that doesn’t work so well on joints, which get rubbed a lot.

To make things look better, use the boil and pop method on Stealth Tech Leonardo’s hips and shoulders. Even though the actual joint is made from a harder plastic, the limbs are more pliable. With the plastic heated, you can easily swap the black peg of the hips for the green peg of the arms.

This is an optional step, but Metalhead will look better if it’s done.

Also, don’t bother with the pegs for the knees and the elbows, as they’re different sizes.


Step 4 – Tape Arm Joints

That green stuff on the joint is tape.

The reason it’s on there is because Metalhead’s shoulder joints had a thicker peg, so the hole in the torso is thicker. Leonardo’s arm is just going to wobble around in there.

The easiest way to thicken up the peg is just to wrap some tape around it. I used painter’s tape because it’s not overly adhesive but it’s malleable, letting it stretch and form the proper shape just by wrapping it around the peg.


Cut a thin strip of the tape and wrap it around the peg a few times, testing with the torso until you get to the right amount of thickness that it sits in there tightly. After that you can trim off any excess that’s sticking up around the peg.

Metalhead Shoulder Test

There are probably other methods like using plastic epoxy to make the hole smaller, and if the tape ever causes a problem or comes loose I’d probably use the epoxy method, but the tape seems to be fine so far, even moving the arms around a lot after the mod.


Step 5 -Off with his hands!

If you like the look Stealth Tech Leonardo’s hands and forearms, you don’t need to do the next few steps. While it doesn’t have Metalhead’s cool hand guards, the big and blocky features do fit well with the robotic style.

But I prefer the look of the hand guards, and I want Metalhead to keep keep the forearm swivel.

And that means Leo’s hands have to go.

So go get an X-acto knife or some other kind of sharp blade, and start cutting just above the black wrapping details on Leo’s forearm. You can go a bit higher, but you have to make sure you don’t cut into the elbow joint. If you stick with where I’ve told you, that won’t be a problem.

Leo Forearm Where To Cut

Clean Cut

A sharp blade should press easily through the soft plastic and make a clean(ish) cut.


Step 6 – Plugs and Bolts

For the next step, we need to cut a few things off of Metalhead’s arms.

During step 2 the forearms were popped off, and during this step we’re going to take  sharp blade and trim some things off of the upper arms and shoulders.

The first things to trim off are going to be the nuts and bolts that decorate Metalhead’s shoulders and elbows. To do this, cut a section of plastic below the bolts and then trim around them, making it easier not to accidentally cut into the bolt itself.

Shoulder Bolts

Elbow Bolts and Forearm Plug

You’ll also want to cut off the plugs for the forearm swivel. Use the same method that you used with the bolts, cutting well below the plug and then trimming up from there.

The part you need is the hard plastic plug itself, and the softer black plastic just below it.

Plug Where To Cut


Step 7 – Glue!

This is the step where Metalhead starts to come together!

Start by gluing the pegs for the forearm swivels onto Leonardo’s forearms. I used Super Glue by Loctite, coated the bottom of the plug, and then pushed it up against the cut part of Leonardo’s forearm until it stuck.

Try to get it centered, and try not to get glue on the rest of the plug.

Forearm Plugs Where To Glue

That picture shows Leonardo’s forearms popped off from the upper arms, but there’s no need to do that at all. I was just attempting to see if the black elbow from the knee would fit in the elbow. It doesn’t fit, so keep the green peg for the elbow.


Once the glue has had time to set, pop the forearms on there and do another test fit of the tape for the arms. If that looks good, pop the torso apart again and glue around some of the edges, making sure not to glue the holes for the arms and legs. Put the torso back together and hold it tight until that glue sets, and then you’ve only got a few more things to glue on Metalhead.

And those few more things are the nuts and bolts that you cut off earlier. Glue the smaller yellow parts to the elbow pads, and the glue the larger gray parts to the shoulder pads.

Metalhead Modded

Metalhead Side View


Some plastic fodder or even some twist ties could be added to the forearms to bulk them up a bit around the armor, but so far it’s not something that bothers me enough to do it. If I do, I’ll post a guide for it.


And that’s it! You’ve now got a modded Metalhead with more articulated arms.

It looks even better when painted.

Metalhead Painted

And by ‘painted’, I mean ‘digibashed’… But it should look something like that.


So, dear readers, did this guide help turn your tin turtle from a no elbow nobody into an articulated automaton, or did it stink like sewer? What’s your favorite pizza topping?

Leave a comment and let me know!

And don’t forget to use the boxes below to share this Nickelodeon Metalhead Custom Arm Mod guide with all the unarticulated turtles in your facetwit friend-0-reddit.

~Matt Booker

7 thoughts on “Nickelodeon Metalhead – Custom Arm Mod

  1. I’ve only had the courage to try some of the less invasive mods on your site, like those that involve carefully shaving off bits of plastic with the patented MattBooker™ blade grip, haha. This is probably one of the most drastic mods I’ve seen here, and I’m glad to see it turned out so nicely.

  2. I’ve thought several times about trying to articulate Metalhead’s arms, but I never came across a mod idea I really liked.

    This one looks pretty good, I must say.

  3. I gave Metalhead shoulders with donor balljoints from a HALO figure, haven’t worked out how to re-attach his shoulder boxes without restricting the joints yet tho…


  4. Thanks, Arnisboy! Just be careful holding those sharp objects in ways I in no way officially endorse doing. :) The plastic on this does cut pretty easily, though, with cracking the torsos being the most difficult part.

    Thanks, Heli! Metalhead sat on my shelf for a bit, and for a while I thought I wasn’t going to bother with it, but Leo’s arms were just what I was wanting for it. The main drawback to this one is that the forearm guards are a bit too wide compared to the forearms, but that stands out a lot more in pictures than in person. Still, a bit of wire wrapped around there and then painted black would fix that, and match up with the ribbed details on the legs.

    Haha, L.T.. :)

    Doug, did you use the rest of the HALO fig for the arms, or was it just the shoulders? As for the shoulder boxes, if you don’t end up using them, don’t feel too bad as they aren’t that show accurate anyway.

    ~Matt Booker

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