Hot answers tagged adhesive
Some sort of 2 part epoxy should hold up pretty well. Araldite is a common brand in the UK. For best results, try to remove the old glue so the bond is to the plastic itself, scuff both surfaces with sandpaper, then clean with something like alcohol to ensure the best bond. Allow to dry before applying epoxy. It's important to use the specified proportions ...
I have a similar torch/Flashlight and have had the exact same problem.. I fixed mine with a product called Q-Bond. On my flashlight, the magnet was flush (ie not resessed) and I was able to build up a sidewall to add extra strength. Needless to say... the magnet has not come off (and yes, this is from years of camping in the heat/cold/rain etc.)
You can use a soldering iron with a small pointed tip to heat the perimeter of the recessed area the magnet sets in. After it heats up, put the magnet in place, and the tip of the iron about 1/4" away. Then push the iron down and towards the magnet until the plastic melts and some of it overlaps the magnet, or, wedges it in place. Do this 3 or four times ...
Only top voted, non community-wiki answers of a minimum length are eligible