How to Magnetize a Carnifex
Equipment:

Power drill.
Circled in the red is a 1/8 inch diameter drill bit, this is the bit that will make your magnets fit perfectly.
Circled in black are all the smaller bits that are smaller than the 1/8 inch, these will aid in the drilling.

Modeling Knife
Super Glue
Small Ruler
Small Magnets
Circled in red are MAGCRAFT® 1/8 inch in diameter and 1/16 inch in height rare earth neodymium magnets.
Optional : Green Stuff
Drilling Holes:
First drill a hole in each of the arm slots on both sides of the body with the 1/8 inch drill bit.
Scything Talons positioning:

I recommend posing the talons like the picture above suggest, the forearm is parallel to the chimney stacks. This is only a recommendation you can pose the talon however you like, but just make sure that when they are magnetized they don’t tangle up with any of the other arms/guns.

Since I’ve already glued my carnifex body, I’ve made a green stuff dummy of what you might see. The idea here is to remove some of the guess work as to where you will need to drill for your arm. So assuming you’ve already drilled a hole on the body’s arm socket, place the arm in the socket and look from the inside, posing the arm where you want. Now get a pointy tool (I used my filing tool) and poke a dent on the arm. This dent will be where you will be drilling. (Yes this step can be a bit tricky since the arms don’t stay in place very well, maybe get a friend to hold it still)
Time to drill

Go and drill with the smallest bit you have where you placed your little mark. Then use a slightly bigger bit and then the next bigger one until you get to the 1/8 inch bit. Doing it in an increasing size sequence makes drilling a lot easier and you can fix up the position if it is off.
Tip: I highly suggest that after every drill bit you use you go and check how well the arm aligns with the hole on the body slot.
After you’ve drilled the hole in the arm use your knife to cut off some the resin that is sticking out from the rim.
Placing the Magnets:
Assuming you have drilled holes on all the different arms and guns (excluding the Venom Cannon and Barbed Strangler)
Placing magnets on the body’s arm slots:

Firstly get a stack of magnets and place one in each of the arm slots on right side. I did this with green stuff. I got some green stuff and sealed the holes from the inside and then stuck the “magnet rod” in and the one magnet got stuck with the green stuff. However you can just use super glue though you will need to be patient with the drying.
IMPORTANT: Make sure the magnets on the right side on the body are facing the same way.
IMPORTANT: When putting magnets on the other side of the body, I recommend that they are opposite to that of the other side. An easy way to do this is do as the picture says, get your magnet “rod” that is sticking out of the right side of the body then without flipping the rod stick pointing end on the left arm slots.
Now that your arm slots have magnets glue the 2 halves together.
Note: Don’t glue the top carapace yet.
Placing magnets on the arms:

Placing the magnets on the arms is very easy. As the picture shows all you need to do is make a magnet rod and stick it to the arm slot on the body, then get your arm piece and jam the magnet in the hole you drilled out. If you used a 1/8 inch drill bit, you shouldn’t even need superglue. Do this for all the arms you’ve drill out.
Placing magnets on the carapace:

First get one carapace and drill a hole around where the picture shows. Of course, you first poke a dent with your pointy thing, then use your smallest bit and work your way to the 1/8 inch bit. (Try not to drill too deep)
Now since you want the position of the magnets on each of your carapaces close to identical you will need to do some measuring before you drill out the other carapaces.

So measure from that little top corner to the center of the hole you made. Keep track of this number.
Now with the measurement drill holes in the other carapaces.

Now that you drilled the holes on the carapaces place the magnets into the holes using the “magnet rod” technique to keep them all the same polarity.
Assuming you have glued the 2 body halves together it is time to drill a hole for the magnet for the swappable carapace.

So from what you measured before from the carapace drilling part you will need it again. Looking that the picture closely as to where to start measuring, you want to start at that little peak, not the place where the top carapace joins the body. Then as usual you measure the distance down the line where the body halves meet and use your pointy tool poke it and drill.
Then make a magnet rod stick it to a carapace and the other end goes in the hole, the magnet should not be sticking out, it should be a smooth surface. (Super glue if necessary)
Placing magnets in the head:
Drill a hole in the body where the head slot is, (Use the drilling method stated above) and then stick a magnet in the hole (doesn’t matter what orientation) super glue if needed.

Glue the head together and clip the peg sticking out of the back, smooth it out with a knife.

Drill a hole where that peg used to be using the same drilling method as before, smooth it out with a knife.

Make magnet rod, the head goes in other end.
Placing magnets in the waist:
Assuming you had not glued the top carapace to the body yet.
There is hole a in the body where the waist peg goes in, this hole is not big enough to fit a magnet, so get your 1/8 inch bit and widen it.

This is a cross section of the waist part, the hole is big enough to fit 2 magnets in. You want only one magnet and the magnet should be the top magnet in that hole. Super glue it in place.

Clip the peg off that round thing and smooth it out with a knife. Then super glue a magnet where it was.
OPTIONAL:
Placing magnets in the feet and base.

Drill holes in the feet using the drilling method, place magnets in feet with magnet rod method. They should be same polarity. As the picture says measure the distance between the two magnets from the center of each magnet, keep track of this number.

Place your carnifex on its base, roughly mark down where one of the feet is with your pointy tool. Drill a 1/8 inch hole there. Now the distance to the next hole is whatever you measured before so drill the hole there. (The magnets do not necessary have to be placed that far back as the picture shows)
Finally the last part
Placing magnets in the Venom Canon and Barbed Strangler:
I did this part last after I glued the body halves together so anything I say here are just rough estimates.

I suggest you drill a hole perpendicular to the bicep for the gun arms.
Then drill holes into the guns where the feeder tube will go and place a magnet in there. All those magnets should be the same polarity just to be consistent.
Stick the gun arm to the body and just estimate as to where the tube arm should be drilled.
Barbed Strangler feeder tube arms have a flat part where the arm meets the socket so I just drilled into the center of that. This is only a suggestion.
Since the feeder tube tips are far too small to drill I just cut a piece off.

To do this, stick your gun arm and the feeder arm on the body. Connect the tube in the slot and then mark down how deep the tube goes in with a pen or paint. Then use clippers and cut the tube piece in the direction on how the tube aligns with the slot. Smooth it out with a knife and glue a magnet to it according to the polarity to the gun slot.

If you end up messing up this

Fear not the magnets in the feeder tube and the gun will fix it, as long as it is not way off.
There is a different way to do this, however I haven’t tried it. It is where you glue the feeder tubes to the gun slot first then you don’t have to worry about cutting a piece of the tube off. This way is probably better but it’s an unknown to me but if you glue the tubes together you can’t make a super gunfex.

Rawr!
So that’s my tutorial to how to magnetize a carnifex, When I did this, it was not too hard, with the “magnet rod” method I didn’t have to worry about fumbling with the little magnets and accidentally flipping the polarity and having a 1/8 inch drill bit and using 1/8 inch magnets made it very easy to place magnets in the slots I drilled out.
Hope you enjoyed reading this tutorial and learned some tips and tricks that you can apply not only to magnetizing carnifexes but any other models as well.
Thank you.