This is a heavy-duty spice rack that uses almost no support material (see the photo of support material layout.) If you only have tiny plastic half jars of McCormick spices you could easily use one magnet per jar, instead of two. The vertical arms keep spices from falling out when someone slams the fridge shut or bumps into them. The arms are reinforced to reduced the chance of snapping off. You can read the labels but not have your spices fall.

You can print single, double, triple, quadruple, or quintuple holders. The more jars it can hold, the better it stays on the metal as there are more contact points. In the photos you can see that I use a single holder for my most commonly used spices, salt, and pepper, so they can come with me and stick to the stove while I cook. I like my spices accessible but also out of the friggin' way!

When building these, first buy magnets, then print the magnet test STL file. The magnets I used are in the photos. I bought them from Home Depot for $4.50 per pack of six. The magnets should drop in snugly or lightly pop into the magnet test piece. If they don't, try scaling up or down by 0.5-1.0%. Scale the whole model to match your successful test so the magnets will fit.

When you print the full model. Be careful about cleaning out the support material from the magnet holders. If you deform the edge, the magnets will need to be forced in by popping them in with pliers.

To glue the magnets, use super glue or foaming gorilla glue. I used super glue. First, I made a shallow circle of glue inside the magnet holder. Then, I popped the magnets in, careful not to bring them close to each other and suck them back out of the holder! Then, I made another light circle of glue around the circumference of the inserted magnet so it filled the gap between the magnet and the plastic. Then, as in the photo, I used extra magnets, or some washers, on the opposite side of the magnet holder, so the magnets would be held in place very tightly as the glue dried.

After the glue dried (give it at least 4 hours.) I roughed up the back of each magnet with a file and some 220 grit sandpaper. This increases friction and keeps the magnets from slipping off the shiny, slick side of my fridge.

It will not hold three popcorn seasonings jars in a row, as they are a tad too large, but will hold one or two! I also use one to hold a little bottle of PAM spray oil, which is also handy to stick to the stove when cooking.