Hello Alex! Before making the current burn-wire mechanism, I actually experimented with using a dissolving PVA release. It turned out to be too unpredictable so it led me to find a device called a galvanic release (Galvanic Timed Releases for Researchers • International Fishing Devices) which essentially corrodes away after a set amount of time. Although the magnetic release is definitely something I am interested in researching more about, in the meantime you could use the burn-wire in conjunction with a galvanic release to have that additional fail-safe!