Quote:
Originally Posted by Retired Starman
As a robot inspector, I'll accept any glue which specifically says in its literature that a recommended use is to glue polycarbonate, but if it isn't real polycarbonate cement, expect a big eye roll! And expect to show me that product documentation.
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There's at least one other special case that merits consideration: glue that
is polycarbonate. Granted, that's pretty unlikely, but I know of at least a few adhesives that contain small beads for setting the bond gap. It's not inconceivable that polycarbonate could be an ingredient, making it a "polycarbonate glue". I don't think that's what the GDC intended, and I wouldn't advise trying that for new designs...but in the unlikely event that a team already used this substance, they might as well bring a datasheet listing the ingredients, and see what the inspectors think. (But be prepared to change it....)
I wonder if the GDC intended the rule to refer only to ordinary solvent-based cements (as described above), or if they considered more exotic adhesives? I also wonder whether, on balance, it would have been more useful to allow any glue used only to join polycarbonate pieces. (Wasn't sticking plastic together the core intent? I say that, because solvent cements don't really work on anything but certain plastics, so it's reasonably likely that they didn't expect teams to use the glue to attach plastic to the rest of the minibot. Of course
UV-curing multipurpose adhesives designed for polycarbonate exist, and would work for that purpose.)
And as for datasheets, Loctite's are excellent; search for "Loctite [number] TDS", and you'll get a lot of good information on best practices.
For reference regarding what works (but not necessarily what's legal), this
Handbook of Plastics Joining looks helpful. See table 27.9 on page 305 for some information on polycarbonate and various adhesives.