Has anyone had direct experience use JB Weld on metal to PLA bonding?

So the YouTube talking heads all talk about gluing together two parts. I’ve performed my own testing between, epoxy, plastic glue, model cement and the overall winning performer was SCIGRIP 10315 16 Acrylic Plastic Cement. But that only works for chemically welding plastic on plastic.

My use-case is to bond Molybdenum Rare Earth Magnets to plastic. Normally I would embed two magnets in the filament while it was printing but this case does not lend itself to that. My experience with JB Weld is that it is 90% hype and has a limited use-case. Only certain applications work and one needs to encase the objects being bonded in the material. Then it works - somewhat. But in the use of bonding two smooth surfaces together, it was not up to what it advertised.

Here is my simple test case.

  • Take two objects and glue them together.
  • Then after they have fully cured, I then take them in a vise and try to pry the other object off to see what kind of strength it has.

In the world of plastics, a successful test by my definition would be that the plastic material surrounding the bond would fail before the bond. This is no different than tests conducted with metal welding. You know you have a perfect bond when the bond strength exceeds to material around it.

In my experience with JB Weld, the only use-case I found was to first rivet or fasten together two metal components, then smother the joints with a generous amount of JB Weld to ensure that the joint movement is minimized. However, what it does not do in my experience, is hold two pieces of material together with a strong bond. I’ve had better luck with fiberglass resins than JB Weld.

Thoughts anyone? Perhaps there is a method to use JB Weld than I am missing but more importantly, has anyone tried this with PLA?

Molybdenum Rare Earth Magnets are highly pollished so no matter what you use to glue, it won’t stick. Somehow you will have to try and embed the magnet into the piece and then use the resin to re-enforce the magnet.
You could try and rough up the magnet for the glue/resin to stick and test, but it may lose some of its magnetic strength.
I have used and loved JB Weld but never tried it on PLA

I bought some JB Weld recently and finally got round to trying it out yesterday/today to try and remove some cross head bolts that has stripped - based on some inspiration with people suggesting it might be used to remove stripped hex bolts from BL extruders.

Fixed some old screwdriver bits to the striped bolts with jb Weld yesterday afternoon - then lunch time today it seemed to be stuck fairly firmly - so I tried using it to remove the stuck screws.

Totally useless for me - it didn’t seem to bond the metal to metal hardly at all.

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I did repair a momentary switch on my commercial vacuum sealer with it, something else you may want to try for the hex head screws is getting some liquid steel epoxy from an Auto supply store. that gets super hard after a couple days of curing.

The vacuum sealer repair is one reason I got on the obsession to get a 3D printer lol…