A Low-Cost Uncoupling Magnet Alternative
Go ahead, call me cheap, but who doesn't love a good bargain? Shortly after spending nearly $70 US on a set of 8 K*D*** brand under-track uncoupling magnets, I decided to see what alternatives were available. Like cork roadbed and ballast, commercially available hobby products are expensive and that adds up on a larger layout!
Off to Amazon! A quick search uncovered inexpensive Neodymium Bar Magnets that measured 60x10x3mm. A pack of 12 was just $9, a few cents more than one of the commercial magnets I just bought. It was a small risk because I could use these for other purposes. A day later they arrived and it was time to test.
I slid 2 magnets off the stack and carefully aligned them side by side. The two magnets were just a few mm longer than the commercial magnet and the width of the HO track ties. The commercial magnet was close to 50% wider, but that was likely to allow it to work in O scale. I used a scrap of roadbed foam and gouged a rectangular hole and pressed the two magnets in, then used a couple of sewing pins to secure a piece of flex-track over the magnet. Added two cars and tested the uncoupling and delayed-action capabilities. SUCCESS!
These were the magnets that I purchased, and at 20 for $16, it brings my per-uncoupler cost from over $8 to just $1.80. There's virtually no difference in installation process - just cut a rectangular hole and slip the magnet in, then lay the track over the magnets. I didn't use any of the double-sided tape that came with the magnets, so that's an added bonus to use elsewhere. The commercial magnets are rubberized and use a metal plate to increase the magnetic field. I found that this was unnecessary with the Neodymium magnets. The photo below compares a Kadee 308 with my Amazon alternative installed in my layout.
You could probably use a single magnet under the track for N scale, and possibly even use the shorter 40mm magnets. I have no way to test O scale, but - thinking "if 2 is good, 3 must be better!" I was proven wrong! Nothing worked with 3 magnets. You might need to use 4 or a steel plate to distribute the magnetic field in O scale. If anyone figures this out, be sure to post a comment with your results!
That's it for this installment. Just a quick share to help your operating budget go further!
More Info
If you aren't familiar with Delayed Magnetic Uncoupling, I suggest that your review this article on the Kadee Website.
I use manual uncoupling methods when the cars are easy to reach, but when they are along the backdrop or I need to reach over structures, I use a magnetic uncoupler.