In 3D printing it is a well known trick to use Acetone to smooth/dissolve prints made from ABS plastic. Most articles call acetone a "solvent" of ABS but after some experimentation with PLA plastic and THF "solvent" I get the feeling "solvent" may be too vague a term. The main observable difference is Acetone seems to turn ABS into a slurry. This slurry can be used as a glue or a filler because once it dries you're left with acetone plastic in the same shape as the slurry. THF on the other hand just seems to destroy PLA plastic. No slurry is produced, the plastic is just eaten away. My hypothesis is the THF must be breaking down the polymer chain of PLA, thus permanently destroying it. I'm guessing Acetone must be doing something different to ABS, as the plastic doesn't seem to get destroyed. Does anyone know definitively what's going on between ABS and Acetone chemically? Thank!