Alternate title: "Why the Hell Didn't I Do This Years Ago?"
Dilemma: I bought a box of Assault Marines. I can only have one Sergeant. There are a ton of options to equip him with. What should I give him? What if I change my mind after I make him?
What you see above is the final product. An assembled and painted Assault Marine with all of his arm options laid out around him. He is fitted with magnets.
Space Marines are a great thing to try your hand on with this technique. Everyone's got some lying around somewhere, and their arms are bulky enough to actually hold a magnet. Add to that, the shoulderpads seriously hide that there is a magnet in the armpit.
Here's what you need:
Magcraft makes a line of magnets that are a 0.125 inch diameter disc. (You can buy them on Amazon) That's the smallest they make, so we'll be using those for now. (note: there are smaller on other sites, but they're very hard to work with, and I'll cover them later with more advanced conversions. For now, let's stick with these.) They come in a pack of 100 magnetic discs for about $9. Next, get yourself a 1/8" drill bit (1/8" = 0.125", see where I'm going here?) and a pin vise. Make sure the pin vise can hold 1/8", as not many can. That size bit is generally too large for a pin vise, but they do make them. The large one in that link is the one I use for the 1/8" bit. The second largest is what I use for the 1/16" drill bit.
Now, once you have the materials the rest is rather simple. After gluing together the torso, use the drill bit+vise to make holes where the magnets will go. Also, drill a hole in the shoulder part of the arm you want to attach. Try a "dry fit" to make sure the hole is deep enough that the magnet sits flush in the piece.
NOTE: The torso was tricky for me, as it was hollow. When I attached the second magnet to the other shoulder, it shot through the torso bit to the other arm (they're that strong). I would suggest reinforcing the middle of the torso with a bit of greenstuff first. Also, before you super-glue the "mate" magnet, double-check that you have the correct side facing out (they should attract each other.) You don't want to finish gluing your model's arm together just to find out that it is violently propelled away from the model's torso when you try to put it on.
Let everything dry before you try them out.
At this point, feel free to enjoy your model:
Now that you have the basics, you are only limited by your imagination and creativity.
Another example of what you can do with magnets?
Oh yeah. BOTH turrets.
Click here for Part 2