you can join about any materials (with holes, etc) and of any ´normal´ size with this technique.
neither the form of the opening (round, oval, rectancular, wide, narrow, narrowing, ...) nor the thickness of the material (unless you go ballistic) matter. you will create some kind of *rivet*.
_ material/s to be joined
_ drill etc to make openings (unless already made)
_ knife or scissors
_ plastic (bottle)
_ solder iron (or, in emergencies etc, another form of heat plus a metal object to heat up)
ok, here we go (& please, be aware that those joins dont support loades/charges like ´regular´ hardware):
Step 1: Holes, Slots, Etc
make holes etc (unless, s.a., already found in the material)
btw: whatever you join doesnt have to be solid, you could also use that technique on pipes etc
Step 2: Cut Strips of Plastic
here i use a plastic-bottle.
cut out any section you seem fit, straighten it out somehow
Step 3: Make a Coil
roll up the strip in some coil, the tighter the better
cut off as desired
Step 4: Insert Coil in Holes
push/twist the coil into the material you want to join
leave some extra on each end (how much extra depends on what you are doing... just play around)
Step 5: Burn/melt Down the Ends
here i use the good old soldering-iron
(you might wanna take a look at that https://www.instructables.com/id/Diy-Custom-tips-... )
little by little melt down the protruding plastic and form a ´head´, or whatever shape/thickness you prefer
let it cool off, flip the object, do the same on other side
Step 6: Done
for a quick demonstration i put another ´rivet´ next to it.
obviously, the more jonts you make the stronger the connection (in other words, like all of us... not just here)
as always: buy less, work less, play more. thank you all.