Choosing the right magnets for your bases

Magnetising bases of our rank and file troops has become a popular method to help our troops stick together in battle. Some players may even use it to facilitate transport from battlefield to battlefield. And some players go as far as using magnets to make their mini’s modular. Imagine changing the weapons of your dreadnaught or tank on the fly! Or to piece together your dragon, but remain able to take down the wings, tails and heads for transport.

The popularity of these methods has spawned a fair share of “how tos” and guides, but few of these actually cover different approaches. Many reviewers (like me) tend to buy only one brand.. so how does one choose the right magnet?

Types of magnets

Before digging deeper, let me list the main types of magnets you may find on the market and may find in tutorials:

  • Ferro magnets are the classic, black, whiteboard magnets. They come cheap but tend to be too large or too weak for our modelling needs, unless it’s to magnetize large boards or terrain pieces.
  • Magnetic strips are fairly weak, but easily cover the whole base. At that size, they easily get the job done.
  • Neodyum magnets, also known as “rare earth magnets” are 18 times as strong as Ferro magnets of the similar shape. In small shapes and big numbers, they stay cheap and do exactly what we need.

For the remainder of this post, I’ll stick to neodyum magnets and magnetic strips.

The movement tray

Magnetizing the bases is one step of the process. The other step is making a base on which the magnets will stick. Depending on the material you’ll use for the movement tray, your magnets will work more or less effectively. Popular methods seem to be:

  • A metal plate for movement tray which is either 1mm or a bit thicker. It offers a fantastic grip for the magnets. I’m guessing easily 80% of their strength. The material is very strong and serves directly as the movement tray but… It can be very challenging to cut to the right size and shape. The difficulty of handling the material makes it an unpopular choice (unless among people who have the equipment to handle it).
  • Washers can be glued on the movement tray where the models should stand. This is cheap and effective. The washers offer a good grip, but.. You need to align them perfectly with the magnets and the models in the unit. This may hamper the reusability of a movement tray.
  • Another magnet can be glued on the movement tray instead of a washer. This helps if the model is particularly heavy and you want to “double up” the power of the magnet. But generally… you won’t need that.
  • A tin-plate is a more accessible material (any old vintage cookie box will do) and more manipulable as the metal plate. It still offers a very good grip. I have no exact measure on the strength, but I’d say 50%-60%. While it’s easier to get and manipulate, it’s still difficult to get the material right. You’ll also have to glue it on a movement tray as the tin-plate can’t bear the weight of the models.
  • Ferro paint is a very easy to use solution. Just paint the movement tray with this ferro or magnetic paint and you’re set. You may have to apply several coats for it to work however, and even so you can’t depend on the full strength of the magnet.
  • Magnetic rubber is offered by some shops. It’s easy to manipulate, cut in shape and glue as needed. The rubber actually helps in the grip of the models so it reduces the required strength a bit. The only downside is that it tends to be a pricy solution.

An important note regarding the movement tray: I’ve read that some people will stick the metal, tin or magnetic sheet underneath the movement tray so it’s “less visible”. This can work just fine, but the magnetic strength is reduced significantly when distancing the metal from the magnet by 1mm. Double the strength of the magnet if you want to do that.

Required strength

There is no clear definition on how much strength is really needed. The pletora of movement tray materials used make it difficult to work it out. We can, however, make an educated guess… or give ballpark figures that may push you in the right direction.

The strength of a magnet is often measured in how much weight it can carry. This is the strength the magnet would offer when holding the model upside down. But we also want it to have a good grip when held vertically or slanted. According to supermagnete.de, a neodyum magnet can carry only 15% of its weight strength, and a magnetic strip can carry only 25% when held vertically (link). This means, when sliding the movement tray or tilting it, your models could still end up sliding.

To make a model carry 100% of the model’s weight when sliding the movement tray, or tilting it, we need a magnetic power 7 times the weight of the model for neodyum magnets and 4 times the weight for magnetic strips.

Assuming you’re not using particularly heavy bases (such as real stones on your bases), then the following ball park figures should help.

Using Neodyum magnets
Model\Tray Metal tray Thin metal sheetTin-plate
Washer
Magnetic Paint
Metal sheet under
the tray
5 gr
plastic model
44 gr 59 gr 120 gr
25 gr
tin model
219 gr 292 gr 600 gr
Using magnetic strip, strength per cm2
Model\Tray Metal tray Thin metal sheetTin-plate
Washer
Magnetic Paint
Metal sheet under
the tray
5 gr/cm2
plastic model
7 gr/cm2 9 gr/cm2 20 gr/cm2
25 gr/cm2
tin model
32 gr/cm2 42 gr/cm2 100 gr/cm2

There’s a few important notes about this:

  • Either material is well capable of covering that. There’s no real “bad” choice to be made, but one solution might work a bit better than the other.
  • Watch out if you place the metal sheet under the tray. That’s the only situation in which you really need to be picky about your magnets.
  • You can use two magnets. If you’re using a bigger model, or if you bought cheaper, smaller magnets and they don’t seem to cover the load that well, check if you can fit a second magnet underneat the base. If they are neodyum magnets, it’s likely you can. Sometimes it’s easier and cheaper to buy a big number of smaller magnets. But in terms of work comfort, smaller magnets are less easy
  • Don’t go too strong. Stronger magnets will give additional security, but at some point, the strength of the magnet may overcome the strength of your glue or even the model’s integrity. You probably don’t need magnets that can pull 2 kg. Your models may prove unable to bear it either.

As example, I used magnets that can pull about 600 grams. Even with a very tin sheet of metal, my tin soldiers would stick like glued:

A note on quality measures

There can be notable differences in the strength of magnets, even when they have the same size and type. Some products are simply made stronger than others. So, when seeing offers for cheaper magnets, keep in mind that these magnets could offer lesser strength. This isn’t necessarily a bad thing! As long as we have enough magnetic power for our means, we’re set and the cheaper we can get it, the better.

For magnetic strips I their strength seems mostly expressed in terms of “weight” it can carry per size, such as kg per cm2. Neodyum magnets sometimes get a strength label such as “N35”, “N45”, “N50” etc. The letter denotes their resistance to temperature. “N” stands for normal room temperatures, which is the weakest score (link) but all we really need (unless you wish to bake your magnets?). The number after the letter denotes the magnetic strength. The higher the number, the stronger the magnetic pull. This is a label irrelevant of size, so a big N45 magnet is stronger than a small N45 magnet, but a N45 magnet is stronger than a N35 magnet of the same size.

If the shop you’d like to buy magnets from doesn’t include a measure of strength or quality label of the magnet, ask them before buying!

The size of the magnet

The size of the magnet isn’t much of an issue for magnetic strips. You want the strip to be as wide as the base by preference and you cut them to the right length. Simple as that.

Neodyum magnets are a different story. Anything up to 2mm high will fit under a games workshop base. At 2mm high, they fit so nicely under a GW base that no green stuff is needed to fix them (just a strong glue will do). If you pick a slimmer magnet, you’ll need to fasten them with green stuff and a good glue.

In diameter, anything between 3mm and 6mm diameter tends to be sufficient. But for sake of completion, here are the maximum size of discs you can fit under the base.

Type of slot in the base Maximum diameter
20mm base
Maximum diameter
25mm base
18mm 23mm
10.5mm 13.5mm
7.6mm 11mm
9mm; 12mm;
6mm; 8mm;

Up to 7mm fits any base, but you can take 6mm to be on the safe side.

Summary

This may have been a lot of information to digest, but we can take a few simple conclusions. Most important is that the current strength of magnets is quite forgiving, so there is little that can go wrong.

For magnetic strips, it’s recommended to use a metallic movement tray or to stick a a metallic sheet on top of the tray if you’re magnetizing tin miniatures. Plastics or resin miniatures will work fine with weaker materials for the tray such as metallic paint.

Neodyum magnets can be as high as 2mm to fit under the base. In circle form, up to 7.5mm diameter will fit under any base but it’s unlikely such a large magnet is required. Size should depend on the strength of the magnet and the model you want to use it for:

  • For a tin miniatures (on foot), you can go as small as 3mmx2mm for a good quality neodyum magnet (N48), or larger if the quality is less if you combine it with a metal movement tray. 5mm x 2mm of N52 quality might be both comfortable and more flexible towards the material you use for the movement tray. If you wish to place the metal layer under the base, take a good quality magnet or a weaker one of 6mmx2mm size.
  • For a plastic miniatures, you can take a neodyum magnet as small as 2mmx1mm. I wouldn’t recommend anything larger than 5mm x 2mm or the magnets might place too much strain on the model.
  • For monster or cavalry bases, the easiest solution might prove to use two magnets from infantry models.

I used 5mm x 2mm magnets, of N52 quality for metal models and core plastics. They are doing a very good job for metal models, but are a bit over the top for the plastics. I might buy weaker ones for finecast in due time. If you’re still out there looking for magnets, I was quite happy with the service delivered by Supermagnete.be, but with the information in this post, I hope you are well on your way in finding the magnet you need from any store.

6 thoughts on “Choosing the right magnets for your bases

  1. I’ve been thinking on how to magnetise my resin bases, now that I have decided to use them for the entire army. The 4mm x2mm ones we order are strong enough but I need to find a practical solution to drill out 4mm holes in 100+ resin bases without sustaining major injuries.

  2. Drilling… would seem like a good option but it may be a challenge to drill a 5mm diameter hole for only 2mm deep. Will it be plastic models placed on the resin bases? It might be worth checking if a 2mmx2mm would suffice in magnetic pull. It might be easier to drill.

  3. Magnetizing 20mm x 40mm cavalry bases:

    I’ve encountered two types of cavalry base. The easier type to work with has three broad bars down the center (around the slots, where slotted). The other type has two additional supports running just inside the two long edges of the base.

    3 mm x 2mm magnets, preferably a pair in diagonally opposite corners, work well on these bases, although using a dremel (or tedious X-Acto work) is needed on the ones with the extra supports.

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