You ever pull apart something that's been sitting outside and find water inside where there absolutely shouldn't be any? I had an old trailer bearing do the same thing, looked like someone injected mayo into the hub. Now I just use the cheap marine stuff on everything, bikes included.

Stud finders work fine if you know how to use them right.

Heating both sides" hit me right in the gut because that's exactly what I did for two years with my first set of pauldrons. I watched every tutorial, read the forums, and still couldn't figure out why my edges kept curling like a bad lasagna. Turns out I was also torching the back while trying to smooth out the front seams, and the heat was pulling the worbla in two directions at once. Once I stopped and just worked one face at a time, it was like a whole new material. I ended up making a little cardboard shield for the back side so I wouldn't accidentally hit it, and that stupid shield solved everything. Now I tell every newbie at my local shop about it and they look at me like I'm nuts until they try it themselves.