thread tape or something similar

[pgh13]

How about Rawlnuts? They are a rubber plug with a metal threaded insert. When you screw into them they get shorter and fatter. They've been around for donkey's years and quote
"For use in virtually any construction material from thin sheet metal to concrete. Fixing expands to fit internal profile even in irregular holes. Resistant to vibration and corrosion provides a waterproof seal."

 

[howy1]

I think they might be called "Toggle bolts"

 

[pgh13]

Trust me.....Rawlnut. They're ideal for situations like this. It's a rubber cylinder with a lip at one end to stop it falling into the panel and a metric screw thread at the other.