A one hour project.
Cousin's family visited, and her kid had this bootleg Iron Man that apparently was favorite of his. You can see by the missing paint and other damage the toy is well played with.
The damage included a missing forearm, and while sculpting a copy of the right arm would be take too much time and effort, giving him an asymmetrical arm would be easily doable.


Made the articulation disk by gluing two HIPS plastic sheets together and using a dremel to make them round and the right size. Used a piece of plastic lollipop stick as a pin. Used another piece of lollipop stick with a piece of paperclip inside as the base for the new forearm.


As the kid is a big Lego fan, I connected the new elbow to a couple of Lego-compatible 1x2 plates. This way the kid will be able to give Iron Man any kind of arm, cannon, or arm cannon his imagination and his brick collection can create.


The original arm's elbow bends less than 90º, but this one can bend nearly 180º when no other bricks are attached to the forearm-bricks.

Told the kid to send me some pics of his creations with this arm once he gets home.

 

Now that's clever! Very out-of-box thinking considering the enhanced play options this kid will now have with that simple lego piece.  

 

Hope to see his designs, sounds interesting and good idea for play patter.

 

Personally I would've installed the connecting bricks with the studs facing out. But still that's an amazing idea and I hope your nephew loves it!

 

Yeah. That was the idea but I installed it backwards by mistake. Easily fixable.

 

Yesterday I got sent this.
No decorative parts, specially nothing that can reduce the range of movement of the elbow or that ball joint wrist he added. The kid cares more for function than looks. I can respect that.

 

That's a really fun solution to save the figure for the kid. Excellent job!