Step 1: Equipment and Supplies
4 oz Round Clear Top Tins [Pic 1]
1/4" x 1/16" Neodymium Magnets (3 per tin) [Pic 2]
Paper Work Surface
JB Weld (or Other Epoxy)
Paper for Mixing Epoxy
100 Grit Sandpaper (or Similar)
Damp Paper Towel
Pocket Knife Tweezers [Pic 4]
Step 2: Preparing the Tins
1) Start with a clean tin. You want them free of oils and other debris so clean if necessary. [Pic 1]
2) Rough the back of each tin with the sandpaper. You don't have to get the entire back sanded, you just want to add some texture for the JB Weld to stick to. [Pic 2]
3) Wipe the sanded tins on the damp paper towel to remove the dust. [Pic 3]
4) Let the tins dry briefly so any remaining moisture can evaporate. [Pic 4]
Step 3: Applying the Magnets
1) Apply equal parts of the JB Weld Steel (black) and Hardener (gray) to your mixing surface. [Pic 1]
2) Mix the epoxy with a toothpick until it is a consistently colored paste. [Pic 2]
3) Apply three small dabs of the epoxy about the size of a sesame seed on the back of the tin using the tip of a toothpick. This seems like too little epoxy at first but it is plenty to keep the magnets affixed. Also, the JB Weld is magnetic. So, if you add too much it will crawl up the side of the magnet and begin to coat the top. If this happens wipe the excess off with the damp paper towel. [Pic 3]
4) Using the tweezers pick up a single magnet. [Pic 4]
5) Apply the magnet to the dab of epoxy. Make sure your aim is true. Since the tins are metal they'll attract the magnets as you get close. [Pic 5]
6) Repeat for each of the tins you're making. [Pic 6]
Allow the JB Weld to cure for 24 hours before you continue with the rest of the steps.
Step 4: Labeling the Tins
Finally, when you're applying the labels make sure you place them with the top of the letters facing the bottom of the tin. [Pic 2] That way when they're stuck on the metal surface you can read them easily from the top.
Step 5: Finished Spice Rack
Instead of your refrigerator door you could also stick them to a sheet of tin hung from the wall, strips of metal affixed to the inside of your cabinet doors or a magnetic whiteboard.
Step 6: Final Thoughts
Tins - There are quite a few different options for tins available. There are both round and square versions and you can also pick various sizes. For the size I've found that 4oz tins work best. First, these tins are compact which maximizes the number you can pack in a space. Second, they hold nearly the exact amount of contents that are included in a commercial spice jar. Finally, buy a few extras in case you have some get badly dented.
Magnets - Speaking of dented tins let me give a bit of an explanation as to why this is version 2.0. When I first did this project I used regular strength magnet tape that I was able to buy in a huge roll. It was much simpler to apply to the tins but the pull force was much less. What ended up happening is that heavier contents, salt for example, would slide down the refrigerator. Also, if a tin was bumped it would fall, often taking others with it. I'm betting I'll never get all of that Old Bay from under my refrigerator. [Pic 1] That said, there is an option if you'd prefer to take the magnet tape route; use high energy magnet tape. This product has double the pull strength of standard tape and should hold much better.
As for neodymium magnets there are lots of options. I think the ones I chose for this project work great. They easily support even the heaviest load (my test was a tin full of large crystal sea salt). However, since I've only used three you can tip the tins and pull them right off without a problem. If you're looking for another option instead of epoxy you could also try the self adhesive discs that K&J Magnetics offers.
Bulk Production - When I first re-did my spice rack for version 2.0 I processed 65 tins in one go. [Pic 2] Some quick pointers for working with this many. First, do one step at a time to every tin. For example, sand every tin, then wipe every tin, etc. To manage the JB Weld a little easier I used a dixie cup to mix it in. Another note on the JB Weld, make sure you move fairly quickly. It took me about 45 minutes to glue all the tins and the JB Weld was beginning to get fairly viscous by the time I finished.