DCM, or 'Methylene Chloride', or Dichloromethane (takes 15 seconds to weld acrylic).If ABS plastic is used Acetone works.MEK works but smells bbbaadd.You could use 5 minute Epoxy glue.You can try PVC and ABS glues from the hardware store.Or double sided foam tape if the plastic nut is sufficiently large.
Methylene Dichloride is sold here, in the UK, under the trade name "Plastic Weld".I keep mine in the fridge, to stop it evaporating.MEK = Methyl Ethyl Ketone. I don't mind the smell. It's not as bad as Acetone.Some of the higher Ketones have quite pleasant smells, one has a distinctive 'pear drops' smell.
What bottles do you use to store your DCM?Would you show an image of the inside of the cap.What do you tell your spouse when you put the solvent in the fridge? I think Weld-On 4 is DCM in the USA.
Do the caps on the bottle have a polyproplyene or aluminum tape seal?
DCM freezes at -97°C so the freezer should work.
DCM is the basis of many commercial paint strippers, so be careful!Allan