Today I needed to glue some PLA plastic from my 3D printer together. The 3D forums all talk about how this is difficult, and I have had troubles. Unless you have a lot of surface or no need for strenght, everything I had tried up until today did not work.
PVA, polyvinyl alcohol, white Elmers® glue, requires porousity. Epoxy works sort of if you sand first but still is not very stuck. Plumbing cement does not work.
Just yesterday for another application I bought some Duco Cement. It is very similar to a “clear acid bottle varnish” recipe from “A Handbook of Chemistry and Physics” 1947 which suggests “dissolving ordinary toothbrush handles in acetone”. The question is, “What was an ‘ordinary toothbrush handle’ made of?” The answer is nitrocellulose. It makes a great finish and is still used on guitars. It is also, with less acetone, the basic recipe for Duco. It seems, at least at this short try, to work really well.
Given this success I thought that I should also try “Juice”. Juice is a mix that is used to stick ABS plastic to its build surface when 3D extrusion or additive printing with ABS filament. It is ABS filament dissolved in acetone. I am using this mix in a thicker consistency than I use for juiceing my build surface.
Please, please, acetone is not innocuous, vent the fumes and minimize exposure, use appropriate protective gear. Both of these glues are flammable and have low flash points when wet. Nitrocellulose is highly flammable even when dry and not safe to store dry. I am not convinced that the recipe using nitrocellulose is safe. There are many varients of this plastic. My suggestion for this sort of glue is to just buy Duco or another brand. But the Juice recipe seems great, and if you have filament in colors, you can have glue in the same colors.Just follow the warning label on the acetone and practice good hygiene. I am not a safety expert.

PVA Glues
Modified PVA Glues
Hide Glues
Epoxy
Polyester Resin
Weldwood Plastic Resin type glues Calumite.
Wheat Paste
Sodium Silicate