I had to take apart my extruder since my modified design was leaking plastic and now needed a seal. So I thought I needed to clean off all the PLA from all the parts in order to reassemble it most effectively since the surfaces to seal against should be clean during fit-up.
I had read that some REPRAP-ers claimed rubbing alcohol could dissolve PLA, so I tried it.
After 48 hrs of PLA immersion in 91% isopropyl alcohol- no effect.
6 hrs in mineral spirits- no effect on PLA.
I tried methylethylketoneMethyl Ethyl Ketone (2-Butanone) for 24 hrs- caused the PLA to release from metal surfaces with the help of some scrubbing to aid in the release in some spots. It does not dissolve PLA, but turned my black PLA grey where it was thin and did not seem to soften it any.
Unfortunately, I ended up messing up the thermal isolator with a drill bit after soaking as the MEK did not soften the PLA in the isolator tube. Now I will have to make a new one. In hind sight, I should have just left the thermal isolator with the PLA plug half way down it, and left the nozzle interior full and only cleaned the exterior mating surfaces and soaked the compressed air fitting only. That way the plastic in the extruder would conduct the heat and re-melt once assembled (hopefully). Ugggh. 😦
picture of my hot-end v1 prior to PLA removal attempts
I use PLA from Ultamachine http://ultimachine.com/pla who buys from Natureworks 4043D (mfg spec on webpage). I do like that this PLA has full manufacturing specification available and is FDA compliant, made of corn grown in the USA and processed in the USA.