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Best Glue For Magnets On Caches?

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I think different environments might require slightly different applications. Here in the midwest we've got a lot of freezing/thawing and then some nasty hot summer temps. One friend of mine who has done a lot of research on this topic has settled on some type of silicone caulk. He also tends to wrap the container (usually decons) in camo duct tape as extra protection.



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For that, I would think JB Weld. Good stuff. It held part of my radiator together for about 5 years and only broke when some grease monkey broke it. New bond is going on 3 years.....


That is a bond between plastic and metal (can you believe the radiator part is the plastic one! %$#&% - I glued on a metal part to fix it). The metal, however, is a threaded piece of brass. I don't know how well it would bond to smooth metal.... I think it advertises it will and it probably will....

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Use epoxy or something similar. You want something that really sticks well to the magnet under fluctuating hot and cold conditions. Something thick works better than something runny for this technique. Don't worry so much about the tupperware.


Drill a few small holes in the tupperware where you will glue the magnet. Glue the magent on, and let adhesive flow through the holes in the tuperware, and spread out on the other side.


This will essentially create "rivets" that will take the strain off the magnet/tuperware bond. If you use enough adhesive, there should be no problem with the holes letting in water.


It might help (or it may be enough) to roughen the surfaces the magnet and tupperware so the adhesive gets a better grip.



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1/4 drill

1/4-20 bolt

1/4-20 nut

1/4 fender washer

(optional) 1/10 oz silicone sealer



drill hole in magnet and tupperware

place 1/4 bolt through magnet and tupperware and fender washer

(optional) liberally spread silicone sealer on washer before assembly

place 1/4-20 nut on 1/4-20 bolt and tighten as tight as you can get it

give it a 1/4 turn clockwise

place cache on ferrous metallic surface

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This will work. PL Premium 2000 Construction Adhesive. I guarantee it will hold on to anything. The tupperware will break before the glue releases. OK, I haven't actually tested that theory but it's strong stuff. I know, I used to be in construction and I remember if you got it on your hand I would take weeks for it to come off.

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I'm having trouble with magnets peeling off my tupperware caches, probably due to temp extremes in N. Nevada. (Daily 40 degree temp swing) 100 in the summer, 0 in the winter. What works best for you? Thanx, bobthecat

What did you use? Whatever it was it was holding up pretty well on Saturday. :rolleyes:

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While the previous thread referenced earlier appeared to be in regard to initially attaching the magnets, the question in this thread appears to focus on the peeling of already-attached magnets.


While all references to the glue joint are valid, consider for the moment that not all peel situations will be caused by defeat of the glue joint.


Ceramic magnets, depending on the type and manufacturer, can often be stronger in magnetism than the ceramic itself can handle. This can result in frequent chipping, even hairline fractures.


I've been known to create magnet caches using an M258A1 (decon container) with three stacks of three circular ceramic magnets in a line across a side. Great hold. The problem was that the glue joint was always stronger than the magnet stacks, so each "pull" from its hiding place, and each placement back to its hiding place, caused a hairline fracture in the magnet stacks. I might have thought the glue joint failed, but close observation revealed a microthin layer of ceramic still attached to the decon.


In this particular instance, the strength of the epoxy is not the issue, though in all instances it is of paramount importance that the glue joint be as strong as possible. The idea to counter with magnets on the inside of the container is valid; however, one will not get 100% efficiency out of these magnets (because there is a gap between them and the magnet stacks), and in the case of a decon or other micro-sized cache, it severely infringes on internal cache space.


To ensure a strong and thorough glue joint, I favor contact cement over superglues. With contact cement, you know ahead of time both surfaces are thoroughly covered, which is more difficult to do with the time constraints of superglue. With contact cement, less is more: thin layers result in a grip upon initial contact which does not require clamping. Goop it on, and clamping will be required at least through the initial stages of the curing process; it also does not necessarily result in a stronger glue joint. In fact, it can often lead to gaps near the edges as the glue contracts. It goes without saying: you want as much of the magnet surface to have as much contact with the cache surface as possible.


Full cure times for contact cement are rated at 24 hours. I wait 48.


Support from the bottom is not enough with ceramics. The other two options: support from the sides, and support from the top.


Support from the sides can be realized with any kind of caulk. However, for the best weatherproofing, support, and adhesiveness, I use tub sealant (and lots of it). Caulking is great for insulating and general weather protection, but tub sealant is designed for daily contact with heavy volumes of hot water... and both are rated for 35 to 40 years (think you're cache will still be there in that amount of time?). Tub sealant also shrinks significantly during the curing process (rated at one week: I give two, because of the amounts I use), resulting in a tight hold that is envied by most denture users. Finally: unlike caulking, tub sealant can, by itself, be used as an adhesive, a claim recently proven with one of my hybrid containers (I recommend doing this only when glue versus sealant is an "either/or" option, and you're cache demands weatherproofing qualities, as the shrinking quality can make it a little funny to work with).


One advantage caulk has over tub sealant: the silicone in tub sealant does not hold paint. Many caulks I've seen can be painted in as little as an hour after you put in on.


I goop this stuff on in large quantities. If you opt for caulk, it will shrink slightly, but not significantly. Tub sealant will shrink considerably, turning from a white color to more of a translucency. For the greatest hold, you want to wait until the sealant becomes translucent to place the cache, most particularly this time of year. If you put a cache with uncured sealant in cold weather, the sealant will slow or cease the curing process: you will still have hold, but more along the consistancy of fully cured caulk.


In my experiments, the combination of the glue joint at the bottom and the sealant support from the sides has, thus far, eliminated all problems with splitting. I do have one cache (my first test with sealant) which also uses duct tape to support the magnets from the top, but tests thus far with other containers have indicated the duct tape has not been necessary.

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