What size of the magnets do i need?

[Gridlock]

Here´s the army i am using.
2: Haemonculus
8: Grotesques
2: Raiders
2: Venoms
10: Wrecks
1: Talos
1: Cronos
3: Spiritseers
8 Wraithguards
1: Wraithknight

So basically what size magnets will i need to magnetize the weapons, Torso and head??

[Blackadder]

I use 'rare earth magnets' frequently and the rule of thumb I use is the biggest magnets possible and I always try to put a magnet on both the weapon/head/torso and the adjoining piece.

[40kGamer]

I use 'rare earth magnets' frequently and the rule of thumb I use is the biggest magnets possible and I always try to put a magnet on both the weapon/head/torso and the adjoining piece.

Excellent advice!

Always put magnets on both pieces to be connected. (Watch polarity!)
Always use the biggest size possible for the connection.

Definitely use rare earth magnets. If you want to buy in bulk Amazing Magnets is the source I have used in the past... you can get quantity discounts for bulk orders too. I keep a variety of sizes stocked and use disc magnets.

For small arms and delicate pieces usually the 1/16" x 1/32" works.
I also use a lot of both the 1/8" x 1/32" and 1/8" x 1/16" sizes.

For specific sizes you may have to look for magnetizing tutorials specific to each model. Best of luck!

[Deadlift]

I've also started using paperclips as support when magnetizing models. Glued in one piece next to the magnet with a hole next to the other magnet your attaching it too. It stops parts from flapping around when you move them. I followed a video by IDIC Beer to use magnets on the above Wraithknight. It's a good view and easily adaptable to many models.

[CoffeeGrunt]

Also use a good superglue to get them stuck in there. I used GW's Thin Superglue, and the magnets keep pulling out of their sockets. Loctite works much better, or if you really want it to stay put, Araldite would do it.

I agree that the biggest magnet you can fit is the best bet. There are some tricks you can do with polarity, like having a central negative magnet surrounded by positive ones, so that it helps locate the central magnet properly while allowing rotation and providing strength.