I needed a mandrel to use as a form for shaping the Hellboy egg shell. I found a wood egg at a local craft store for $2. The length is about right but unfortunately the diameter is way off. I also don’t know if the film version had a round or flat bottom since it’s very hard to tell by watching the film. I’m guessing there were a couple of versions of the small egg in the film. The open version that you see standing on its own was able to rotate on the box top in the film (during the sequence when Nuada is assembling it) so I’m thinking the bottom had a flat area where it was attached to the table/rotating mechanism- it looks like it does when you get a very brief side view of it in the film. The egg that Nuada is holding in his hand is first the small version (closed) when he takes it out of his pocket, then switches to the large version during the opening sequence and then switches back to the small version (opened) when he removes the elemental bean- all of these appear to have a round bottom but I can’t be 100% sure due to the angles at which it is seen.
In order to make this wood egg work I coated it with a layer of ApoxieSculpt and then turned it on a lathe. I printed out a line drawing of an egg that appeared to be the correct shape and then used that to cut out a template. While turning the egg shape on the lathe I could then use this template to check the shape of the egg. The turned egg is approximately 3 7/8″ tall and 2 7/8″ diameter.
The egg mandrel has to be slightly smaller than actual size due to the thickness of the brass sheet used- I’m starting off with material around .030″ thick but I can run it through a rolling mill if I need to reduce the thickness slightly. Once I anneal it I’ll hammer form it over the egg mandrel and then trim each panel to the required shape. Believe it or not that’s actually the easy part. The tough part of the fabrication is all of the pivot points required as they really can’t have any slop in them if it is to close correctly. I’m still finalizing all of the mechanics but I think I have the assembly sequence and how all of the parts have to fit together mostly figured out.
With the Stargate helmet finished and the animatronic wings well under way I’ve been thinking about making the Elemental Egg from Hellboy II: The Golden Army. This is a project I’ve wanted to tackle for quite a while and after giving it a fair bit of thought I think I have a good idea as to how to make it.
For the film I believe two eggs were constructed; the first actual size (I’m guessing approximately 4″ long with a 3″ diameter, maybe even a bit smaller?) and a second that was quite large that was used for the sequence where the egg opens up to reveal the elemental bean- I’m guessing that it was either animatronic or cable control.
What I want to make is an actual size egg that opens up- an animatronic egg display piece. I plan to do this by having the egg mounted to a base and having servos open the upper section and the lower section of the egg. The servos will be hidden in a box underneath the egg. The lower section is pretty tricky as there are 24 individual plates that open outward and they open at different rates. I would also like to make the bean glow during the animation sequence. At this point I think I have the majority of the mechanics figured out and I plan to construct the egg shell by forming brass sheet over a mandrel. I imagine one of the hardest things to accomplish will be having the plates close properly- it will require very precise fitting and manufacturing of the mechanics.
This is going to be a tough project!
A couple of screen caps-
After a VERY long absence Episode 4 on the Stargate helmet is finally up. Next episode will be about picking servos for your project. For anyone that needs help with their own project just visit the forum and I’ll try to help out as best as I can!
There is a complete build tutorial on Instructables.
DIY Animatronics Forum
As it turns out I wasn’t quite done. After getting everything together I realized the head needed to move up and back, which meant I had to machine a new neck pivot and then adjust the control rod length. Here’s the new neck pivot assembly.
The really fun part was the caps for the fan mechanisms- once I hollowed them out they didn’t fit- doh! I thought I took really careful measurements but close wasn’t close enough so I had to make new linkage parts so I could get the caps to fit properly. I also had to add the the little brass sliding tabs that cover the open gap as the fans rotate- just like on the original movie helmets.
Now the caps fit properly. They’re held in place with magnets and a round socket that fits over the fan mech pivot retaining collar so they can be easily removed if any repairs should ever need to be done.