This is my solution:
1) Firstly I got hold of some standard plastic Games Workshop WOTR movement trays.
As you can see, they have eight recesses to place miniatures in, and have empty spaces underneath (unlike MDF versions), which will be important later on:
2) Next I got some 4mm x 3mm N35 Neodymium magnets from Ebay. I got mine from Spider Magnets who delivered the next day.
I used a small ball of white Superfine Milliput to secure the magnet. This is easy to work with, sets rock hard, keeps the magnet central and is relatively cheap. Green Stuff or No More Nails would work just as well, but the former is more expensive, and the latter a bit messier and shrinks a bit when it dries. At this stage it's a good idea to sort out the magnets so you always put them the same (polarity) way round, as this prevents your movement trays attracting each other and sticking together!
3) Now I bought a couple of hundred repair washers from Toolmaster. These were only a few pounds (£). Buy them in bulk from a hardware store rather than in those small blister packs from DIY stores as this would work out to be very expensive. Take a movement tray in with you and a magnet just to make sure they fit and are actually magnetic!
4) I used Araldite Rapid to glue a washer permanently into each recess. Putting two small blobs on the back of each washer and twisting it around in the recess to spread the glue worked well. You don't need much glue on each. Leave to dry for an hour or so depending on the temperature.
5) Next I used an old nylon paintbrush to spread PVA glue around the top of each movement tray, being very careful not to get any in each recess. I then sprinkled sand over each tray. You don't want any sand around the inside of each recess as this could stop a miniature's base fitting in the recess.
It amazes me that people spend £5 or more on tiny pots of 'magic basing sand' from GW and others- there are entire deserts covering much of the Earth's surface made up of this stuff!
Simply get some builder's sand from a building supplier and dry it out by putting it in an old aluminium take away carton in the switched off oven just after you've cooked something- the heat from the oven will remove all the moisture and a jam jar full will last you for years and cost a few pence.
6) Once the PVA has (thoroughly) dried, I like to really cement it on by using a PVA/ water mix the consistency of milk over the top of the sand. Try not to brush the sand too much as it will start to come away if you disturb it too much. This really needs to dry properly again so might be best left overnight.
7) Next I sprayed the base black. You could use GW or Army Painter black primer sprays. I actually used some left over grey car aerosol primer followed by matt black from Halfords as they are relatively cheap, have great coverage, and never seem to clog up.
8) Once dry, I give the base a coat of Acrylic brown. I used a big tube of cheap Raw Umber from a craft shop- it lasts for loads of terrain projects and is very economical compared to using fine GW or Vallejo acrylics.
10) The final drybrush was done with a light stone colour from a tester pot of acrylic masonry paint. It's a good match for Vallejo Iraqi Sand and again, much cheaper. Hardware stores are your friend when doing terrain and modelling projects! The Cavalry tray on the right simply uses a larger size metal repair washer glued into each recess, and I glued a Neodymium magent into two diagonally opposite corners.
11) The final stages were to retouch the sides of the bases black where some drybrushing had gone over and to give each tray a coat of spray varnish to protect them. Some people prefer green or brown base edges, I prefer black- it's up to you. I chose not to add flock or grass tufts to my trays as I wanted to use them for Harad (desert), Moria (grey dust and rubble) and general (muddy/ grassland) based troops. This is a compromise, but makes more sense (to me!) than having to have different types of movement tray finishes.
Here you can see a plastic Minas Tirith archer with a tiny 3mm x 2mm N42 Neodymium magnet glued underneath his base. I got mine from Spider Magnets and TW Wargames on Ebay. Note that this is a smaller size magnet as it only has to hold a single figure, and the figure bases aren't as deep as the movement trays.
Generally Araldite works well, but you have to be very careful to use a 50/50 mix of the two parts, and REALLY mix it thoroughly, or it can remain 'tacky' and never really set. It also goes off in just over 4 minutes, so you have to work fast! I lightly scored the underside of each miniature base to give the glue more 'grip'. It also works better to put the blob of Araldite under the base then push the base down on top of the magnet on a flat surface, rather than trying to drop the magnet into the glue from above. I've used Milliput for securing the magnets and it works better. It's just messier to mix and takes longer to harden, but when it does it's VERY permanent!
Here is the completed movement tray. Each miniature is magnetically attracted to the now hidden and painted washer glued into each recess of the movement tray. You can easily detach a miniature should you need to do so, but they won't fall off even when held upside down!
The final stage was to buy a 10 Litre 'Really Useful Box and line it with thin galvanised sheet steel. Again, I found someone on Ebay who could cut and deliver sheets to measure very economically. I secured the sheets to the base of the Really Useful Box with those permanent sticky fixer pads. They are strong enough to hold the sheet steel in, but it doesn't involve drilling or bolting anything together, and at a push they COULD be removed- WD40 is good for removing sticky residue without damaging the surface underneath!
Your movement trays will now stick to the steel sheet by the two magnets you glued underneath each one, holding your miniatures securely and ready to be deployed straight on to the battlefield! As you can see, each Really Useful Box will fit 20 infantry movement trays (160 troops) very neatly with very little wasted space.
:O)
