That's true if you're silver soldering, but with JB weld, it gives you plenty of time to set it up... just rough up both surfaces real good before applying the JB weld... it certainly would give you plenty of thread bite having both the t-nut and loc-nut bonded together; making it more difficult to strip out the threads that's for sure... it was just a thought anyway; I'm sure you will find the appropriate solution for your situation.
John M,